[analyzer] Support for naive cross translational unit analysis

[xazax.hun]

Summary

This patch adds support for naive cross translational unit analysis.

The aim of this patch is to be minimal to enable incremental development of the feature on the top of the tree. This patch should be an NFC in case CTUDir is not provided by the user.

When CTUDir is provided:

• In case a function definition is not available it will be looked up from a textual index, whether it was available in another TU.
• The AST dump of the other TU will be loaded and the function definition will be inlined.

One of the main limitations is that the coverage pattern of the analysis will change when this feature is enabled. For this reason, in the future, it might be better to include some heuristics to prefer examining shorter execution paths to the longer ones. Until then this feature is not recommended to be turned on by users unless they already fixed the important issues with this feature turned off.

We will cover more detailed analysis of this patch soon in our EuroLLVM talk: http://llvm.org/devmtg/2017-03//2017/02/20/accepted-sessions.html#7
We will talk about how this works and the memory usage, analysis time, coverage pattern change, limitations of the ASTImporter, how the length of the bug paths changed and a lot more.

Feel free to skip the review after the talk, but we wanted to make the code available in an easy to review format before the conference.

Note that the initial prototype was done by A. Sidorin et al.: http://lists.llvm.org/pipermail/cfe-dev/2015-October/045730.html

Contributions to the measurements and the new version of the code: Peter Szecsi, Zoltan Gera, Daniel Krupp, Kareem Khazem.

[xazax.hun]

In D30691#731617, @zaks.anna wrote:

I agree that scan-build or scan-build-py integration is an important issue to resolve here. What I envision is that users will just call scan-build and pass -whole-project as an option to it. Everything else will happen automagically:)

We contacted Laszlo and we have a pull request into scan-build that is under review. He is very helpful and supports the idea of scan-build-py supporting CTU analysis.

I do not quite understand why AST serialization is needed at all. Can we instead recompile the translation units on demand into a separate ASTContext and then ASTImport?

We did a prototype implementation of on-demand reparsing. On the C projects we tested, the runtime is increased by 10-30% compared to dumping the ASTs. Note that, it is relatively fast to parse C, I would expect a much bigger delta in case of C++ projects. Unfortunately, we weren't able to test that setting due to the ASTImporter limitations.

include/clang/AST/Mangle.h

59 ↗

(On Diff #94814)

Note that the newest version of this patch does not use name mangling, it uses USRs instead. This turned out to be a perfectly viable alternative and we did not see any behavioral changes on the project we tested after the transition.

[dkrupp]

Thanks for the reviews so far.
I think we have addressed all major concerns regarding this patch:

-(Anna) Scan-build-py integration of the functionality is nearly finished (see https://github.com/rizsotto/scan-build/issues/83) (--ctu switch performs both analysis phases at once). This I think could go in a different patch, but until we could keep the ctu-build.py and ctu-analyze.py scripts. Do you agree?

-(Devin,NoQ) In the externalFnMap.txt (which contains which function definitions is located where) Unified Symbol Resolution (USR) is used to identify functions instead of mangled names, which seems to work equally well for C and C++

-(Anna) Dumping the ASTs to the disk. We tried a version where, ASTs are not dumped in the 1st phase, but is recreated each time a function definition is needed from an external TU. It works fine, but the analysis time went up by 20-30% on open source C projects. Is it OK to add this functionality in a next patch? Or should we it as an optional feature right now?

Do you see anything else that would prevent this patch to get in?

[a.sidorin]

Hello Daniel & Gabor,
Thank you very much for your work. This patch looks good to me but I think such a change should also be approved by maintainers.

[zaks.anna]

-(Anna) Scan-build-py integration of the functionality is nearly finished (see https://github.com/rizsotto/scan-build/issues/83) (--ctu switch performs both analysis phases at once). This I think could go in a different patch, but until we could keep the ctu-build.py and ctu-analyze.py scripts. Do you agree?

It's important to bring this patch into the LLVM repo so that it becomes part of the clang/llvm project and is used. The whole point of adding CTU integration to scan-build-py is to make sure that there is a single tool that all/most users could use; adding the patch to a fork does not accomplish that goal. Also, I am not a fan of developing on downstream branches and that is against the LLVM Developer policy due to all the reasons described here: http://www.llvm.org/docs/DeveloperPolicy.html#incremental-development. This development style leads to fragmentation of the community and the project. Unfortunately, we often see cases where large patches developed out of tree never make it in as a result of not following this policy and it would be great to avoid this in the future.

This I think could go in a different patch, but until we could keep the ctu-build.py and ctu-analyze.py scripts. Do you agree?

It would be best to just add the scan-build-py support to the tree, especially, since the new scrips are not tested.

-(Anna) Dumping the ASTs to the disk. We tried a version where, ASTs are not dumped in the 1st phase, but is recreated each time a function definition is needed from an external TU. It works fine, but the analysis time went up by 20-30% on open source C projects.

I am curious which optimization strategies you considered. An idea that @NoQ came up with was to serialize only the most used translation units. Another idea is to choose the TUs that a particular file has most dependencies on and only inline functions from those.

What mode would you prefer? Would you pay the 20%-30% in speed but reduce the huge disk consumption? That might be a good option, especially, if you have not exhausted the ideas on how to optimize.

Is it OK to add this functionality in a next patch? Or should we it as an optional feature right now?

This depends on what the plan for going forward is. Specifically, if we do not need the serialization mode, you could remove that from this patch and add the new mode. If you think the serialization mode is essential going forward, we could have the other mode in a separate patch. (It would be useful to split out the serialization mode work into a separate patch so that we could revert it later on if we see that the other mode is better.)

I see some changes to the compiler proper, such as ASTImporter, ASTContext, SourceManager. We should split those changes into a separate patch and ask for review from people working on those components. You can point back to this patch, which would contain the analyzer related changes, and state that the other patch is blocking this work.

[dkrupp]

Thanks.

It would be best to just add the scan-build-py support to the tree, especially, since the new scrips are not tested.

OK. We will update this patch with the scan-build-py changes and remove the ctu-build.py and ctu-analyze.py scripts.

I am curious which optimization strategies you considered. An idea that @NoQ came up with was to serialize only the most used translation units. Another idea is to choose the TUs that a particular file has most dependencies on and only inline functions from those.

Both of these strategies could work in practice, we did not try them. We implemented the two extremes: serialize all TUs/don't serialize any of the TUs. Both of them could can be useful in practice as is (depending if the user is cpu/memory/disk space bound). I think we could try with the above suggested optimizations as an incremental improvement (and keep this initial patch as simple as possible).

What mode would you prefer? Would you pay the 20%-30% in speed but reduce the huge disk consumption? That might be a good option, especially, if you have not exhausted the ideas on how to optimize.

In this initial version I think we should keep the serializing mode. We just measured that the heap consumption of the non-serializing mode and it seems to be ~50% larger. Probably because the serializing mode only loads those AST fragments from the disk that is imported. But I can imagine that some user still want to use the non-serializing version which is not using extra disk space. So we will add the non-serializing mode in a next patch as an Analyzer option first (which we can turn into default behaviour later on). OK?

I see some changes to the compiler proper, such as ASTImporter, ASTContext, SourceManager. We should split those changes into a separate patch and ask for review from people working on those components. You can point back to this patch, which would contain the analyzer related changes, and state that the other patch is blocking this work.

Allright, we will do that.

So is it OK to proceed like this?

[xazax.hun]

Some of the CTU related analyzer independent parts are being factored out.
The review is ongoing here: https://reviews.llvm.org/D34512

Another small and independent part is under review here: https://reviews.llvm.org/D34506

[NoQ]

Regarding serializing vs not serializing and now vs later.

1. I think we eventually need to provide a reasonable default approach presented to the user. This approach shouldn't be hurting the user dramatically in any sense. Because serializing hurts the user's disk space dramatically, and not-serializing may be slower and a bit more memory-intensive but isn't too bad in all senses, out of these two options not-serializing is definitely preferable as a default approach.

2. Later we should definitely consider the alternative approaches that serialize only some ASTs, with the hope that one of them would turn out to be a better default approach.

3. From 2. it follows that for now it's better to keep both approaches around - as we believe that the ideal approach may be a combination of the two. Therefore it doesn't really matter in what order they land.

tl;dr: I propose to land serialization-based approach first, then land non-serialization-based approach later and make it default, then consider taking the best of the two and making it a new default.

[klimek]

Richard (added as reviewer) usually owns decisions around clang itself. Writing an email to cfe-dev with the numbers and wait for whether others have concerns would probably also be good.

[xazax.hun]

• Patch scan-build instead of using custom scripts
• Rebase patch based on the proposed LibTooling CTU code

[danielmarjamaki]

tools/scan-build-py/libscanbuild/analyze.py

166

I believe you can write:

for line in open(filename, 'r'):

173

this 'with' seems redundant. I suggest an assignment and then less indentation will be needed below

243

not a big deal but I would use early exits in this function

tools/scan-build-py/libscanbuild/clang.py

177

I am guessing that you can use cmd.find() instead of the loop

[whisperity]

The Python code here still uses mangled name in their wording. Does this mean this patch is yet to be updated with the USR management in the parent patch?

tools/scan-build-py/libscanbuild/analyze.py

166

Do we want to rely on the interpreter implementation on when the file is closed.

If

for line in open(filename, 'r'):
   something()

is used, the file handle will be closed based on garbage collection rules. Having this handle disposed after the iteration is true for the stock CPython implementation, but it is still nontheless an implementation specific approach.

Whereas using with will explicitly close the file handle on the spot, no matter what.

173

I don't seem to understand what do you want to assign to what.

[danielmarjamaki]

tools/scan-build-py/libscanbuild/analyze.py

166

ok I did not know that. feel free to ignore my comment.

173

I did not consider the garbage collection. I assumed that out_file would Always be closed when it Went out of scope and then this would require less indentation:

out_file = open(extern_fns_map_file, 'w')
for mangled_name, ast_file in mangled_ast_pairs:
    out_file.write('%s %s\n' % (mangled_name, ast_file))

243

with "not a big deal" I mean; feel free to ignore my comment if you want to have it this way.

[r.stahl]

While testing this I stumbled upon a crash with the following test case:

inc.h

#define BASE ((int*)0)
void foo();

main.c:

#include "inc.h"
void moo()
{
    int a = BASE[0];
    foo();
}

other.c

#include "inc.h"
void foo()
{
    int a = BASE[0];
}

Note that I used a custom checker that did not stop on the path like the DerefChecker would here. I did not know how to reproduce it with official checkers, but the issue should be understandable without reproduction.

With the given test a checker may produce two results for the null dereference in moo() and foo(). When analyzing main.c they will both be found and therefore sorted with PathDiagnostic.cpp "compareCrossTUSourceLocs".

If either of the FullSourceLocs is a MacroID, the call SM.getFileEntryForID(XL.getFileID()) will return a null pointer. The null pointer will crash the program when attempting to call ->getName() on it.

My solution was to add the following lines before the .getFileID() calls:

XL = XL.getExpansionLoc();
YL = YL.getExpansionLoc();

lib/StaticAnalyzer/Core/PathDiagnostic.cpp

391

see comment

[r.stahl]

In a similar case, static inline functions are an issue.

inc.h

void foo();
static inline void wow()
{
    int a = *(int*)0;
}

main.c

#include "inc.h"
void moo()
{
    foo();
    wow();
}

other.c

#include "inc.h"
void foo()
{
    wow();
}

The inline function is inlined into each calling AST as different AST objects. This causes the PathDiagnostics to be distinct, while pointing to the exact same source location.

When the compareCrossTUSourceLocs function tries to compare the FullSourceLocs, it cannot find a difference and FlushDiagnostics will assert on an erroneous compare function.

For my purposes I replaced the return statement of the compareCrossTUSourceLocs function with:

return XL.getFileID() < YL.getFileID();

A more correct fix would create only one unique diagnostic for both cases.

[xazax.hun]

• Fixed an issue with source locations
• Updated to latest trunk

[xazax.hun]

In D30691#878711, @r.stahl wrote:

If either of the FullSourceLocs is a MacroID, the call SM.getFileEntryForID(XL.getFileID()) will return a null pointer. The null pointer will crash the program when attempting to call ->getName() on it.

Thank you for the report and the detailed analysis!
I did not want to get the expansion location since the original code did not query that either, so for now I just handle the case when I can not query a file entry. This case can occur even when no macros are in the code, for example when a PCH is referring to a nonexistent file.

[xazax.hun]

In D30691#878830, @r.stahl wrote:

For my purposes I replaced the return statement of the compareCrossTUSourceLocs function with:

return XL.getFileID() < YL.getFileID();

A more correct fix would create only one unique diagnostic for both cases.

Thank you for the report, I could reproduce this after modifying the null dereference checker. My fear of using file IDs is that I don't know whether they are stable. So in subsequent runs, different paths might be chosen by the analyzer and this could be confusing to the user. I will think about a workaround that both stable and solves this assertion.

I see two possible ways to do the proper fix. One is to check explicitly for this case when the same function appears in multiple translation units. A better approach would be to have the ASTImporter handle this case. I think the proper fix is better addressed in a separate patch.

[dkrupp]

Please fix the incompatibility between analyze-build and lib/CrossTU in the format of externalFnMap.txt mappfing file.

tools/scan-build-py/libscanbuild/analyze.py

563

There is a incompatibility between this scan-build (analyze-build actually) implementation and new lib/CrossTU library.

CrossTranslationUnitContext::loadExternalAST(

StringRef LookupName, StringRef CrossTUDir, StringRef IndexName)

expects the externalFnMap.txt to be in
"functionName astFilename" format.
however currently we generate here
"functionName@arch astFilename" lines.

One possible fix could be to
create one externalFnMap.txt indexes per arch
<collect-dir>/ast/x86_64/externalFnMap.txt
<collect-dir>/ast/ppc64/externalFnMap.txt
etc.
and call clang analyze with the architecture specific map directory:
e.g. ctu-dir=<collect-dir>/ast/x86_64

This would then work if the "to-be-analyzed" source-code is cross-compiled into multiple architectures.

Would be useful to add a test-case too to check if the map file and ctu-dir content generated by analyze-build is compatible.

613

Maybe we could use the full target-triple for distinguishing the AST binaries, not only the architecture part. The sys part for example is probably important too and a "win32" AST may not be compatible with a "linux" AST.

[xazax.hun]

• Update the scan-build part to work correctly with the accepted version of libCrossTU

[xazax.hun]

• Rebased on ToT

[george.karpenkov]

tools/scan-build-py/libscanbuild/analyze.py

45

What would happen when multiple analyzer runs are launched concurrently in the same directory? Would they race on this file?

65

run_analyzer_with_ctu is an unfortunate function name, since it may or may not launch CTU depending on the passed arguments. Could we just call it run_analyzer?

104

Actually I would prefer a separate NFC PR just moving this function. This PR is already too complicated as it is.

121

Extensive hasattr usage is often a codesmell, and it hinders understanding.
Firstly, shouldn't args.ctu_phases.dir be always available, judging from the code in arguments.py?
Secondly, in what cases args.ctu_phases is not available when we are already going down the CTU code path? Shouldn't we throw an error at that point instead of creating a default configuration? (default-configurations-instead-of-crashing is also another way to introduce very subtle and hard-to-catch error modes)

129

Could you also specify what func_map_lines is (file? list? of strings?) in the docstring? There's specific Sphinx syntax for that. Otherwise it is hard to follow.

139

Could be improved with defaultdict:

mangled_to_asts = defaultdict(set)
...
   mangled_to_asts[mangled_name].add(ast_file)

145

Firstly, no need to modify the set in order to get the first element, just use next(iter(ast_files)).
Secondly, when exactly do conflicting names happen? Is it a bug? Shouldn't the tool log such cases?

146

Overall, instead of creating a dictionary with multiple elements, and then converting to a list, it's much simper to only add an element to mangled_to_asts when it is not already mapped to something (probably logging a message otherwise), and then just return mangled_to_asts.items()

161

Firstly, is glob.glob actually random, as the docstring is saying?
If yes, can we make it not to be random (e.g. with sorted), as dealing with randomized input makes tracking down bugs so much harder?

169

If write_global_map is a closure, please use the fact that it would capture ctudir from the outer scope, and remove it from the argument list.
That would make it more obvious that it does not change between invocations.

190

Having an analysis tool remove files is scary, what if (maybe not in this revision, but in a future iteration) a bug is introduced, and the tool removes user code instead?
Why not just create a temporary directory with tempfile.mkdtemp, put all temporary files there, and then simply iterate through them?
Then you would be able to get rid of the constant CPU_TEMP_FNMAP_FOLDER entirely, and OS would be responsible for cleanup.

244

Similarly to the comment above, I would prefer if analysis tool would not remove files (and I assume those are not huge ones?)
Can we just use temporary directories?

255

Same as the comment above about removing folders. Also it seems like there should be a way to remove redundancy in if collect / remove tree block repeated twice.

285

Using JSON-serialization-over-environment-variables is very unorthodox, and would give very bizarre error messages if the user would try to customize settings (I assume that is the intent, right?)
I think that separating those options into separate ENV variables (if they _have_ to be customizable) would be much better.

319

Again, is it possible to avoid JSON-over-environment-variables?

557

mangled_name, path = fn_src_txt.split(" ", 1) ?

584

try/except/pass is almost always bad.
When can the error occur? Why are we ignoring it?

590

The above can be written more succinctly as:
ast_command = [opts['clang'], ...] + args + ['-w', ...]

601

Similarly here, funcmap_command can be generated in one line using +

611

Again, why is this error ignored?

632

In which case is this branch hit? Isn't improperly formed input argument indicative of an internal error at this stage?

718

This blank line should not be in this PR.

tools/scan-build-py/libscanbuild/clang.py

168

I might be missing something here, but why is the ability to call --version indicative of CTU support?
At worst, this can lead to obscuring real bugs: imagine if the user has args.clang pointed to broken/non-existent binary, then is_ctu_capable would simply return False (hiding the original error!), which would show a completely misleading error message.

Just checking func_map_cmd seems better, but even in this case we should probably log any errors occurring on -version call (such messages would really aid debugging)

177

Seconded, would prefer this rewritten using separator = cmd.find('-triple')

tools/scan-build-py/libscanbuild/report.py

270

I understand the intent here, but it seems it should be handled at a different level: would it be hard to change Clang to only write the report file at the very end, when no crash should be encountered? Or make parsers not choke on empty fields?

tools/scan-build-py/tests/unit/test_analyze.py

338

Probably more tests are required for almost 400 lines of functional Python code in this PR.
Would it be hard to have a full LIT-style integration test? E.g. have a dummy script emulating Clang with a dummy directory structure, which would show how all pieces are meant to fit together?

[gerazo]

Thanks George for the review. I will start working on the code right away. I've tried to answer the simpler cases.

tools/scan-build-py/libscanbuild/analyze.py

45

Yes and no. The 1st, collect part of CTU creates this file by aggregating all data from the build system, while the 2nd part which does the analysis itself only reads it. Multiple analysis can use this file simultaneously without problem. However, multiple collect phases launched on a system does not make sense. In this case, the later one would write over the previous results with the same data.

65

We have an other run_analyzer method but still, it is a good idead, I will make something better up.

104

Yes. The only reason was for the move to make it testable. However, we need more tests as you wrote down below.

121

It definitely needs more comments, so thanks, I will put them here.
There are two separate possibilities here for this code part:

1. The user does not want CTU at all. In this case, no CTU phases are switched on (collect and analyze), so no CTU code will run. This is why dir has no importance in this case.
2. CTU capabilities were not even detected, so the help and available arguments about CTU are also missing. In this case we create a dummy config telling that everything is switched off.

The reason for using hasattr was that not having CTU capabilities is not an exceptional condition, rather a matter of configuration. I felt that handling this with an exception would be misleading.

129

Thanks, I'll do it.

145

Nice catch, thanks.
For your second question: Unfortunately, it is not a bug, rather a misfeature which we can't handle yet. There can be tricky build-systems where a single file with different configurations is built multiple times, so the same function signature will be present in multiple link units. The other option is when two separate compile units have an exact same function signature, but they are never linked together, so it is not a problem in the build itself. In this case, the cross compilation unit functionality cannot tell exactly which compilation unit to turn to for the function, because there are multiple valid choices. In this case, we deliberately leave such functions out to avoid potential problems. It deserves a comment I think.

161

"random" here means we don't care. So you are right. glob.glob doc says it is arbitrary but I couldn't find that it is deterministic or not. Probably sorting it will not do harm.

190

Yes, you are right. We are essentially using a temp dir. Because of the size we first had to put it next to the project (not on tmp drive for instance) and for debugging purposes we gave a name to it. Still it can be done with mkdtemp as well.

244

Unlike above, here we do remove non-temporary data intentionally. The user asks here to do the recollection of CTU data for a fresh start. Because there is no "clean" functionality in the analyzer interface itself, this seemed to be the easiest-on-user solution to save him/her an extra effort or a new command.

285

To be honest, I could never make a decision over this. The previous version of scan-build-py used extensively environment variables for everything which ended up in a huge mess and env contamination. There was an effort to reduce this to only a few, well-designated ones. Still there is the need of adding new data to the environment.

584

I think this code is redundant with the if above.

632

An other part of scan-build-py, analyze_cc uses namedtuple to json format to communicate. However, the names are not coming back from json, so this code helps in this. This is the case when someone uses the whole toolset with compiler wrapping. All the environment variable hassle is also happening because of this. So these env vars are not for user modification (as you've suggested earlier).

tools/scan-build-py/libscanbuild/clang.py

168

The original idea was that clang can give information about CTU support itself. However, it never happened because the analyzer is so deep down in the system. So I am open to remove the clang binary check here. However, clang binary is needed anyway, so the whole toolset will still throw an error later on not having a clang binary.

[gerazo]

The code modifications are coming soon (after doing some extensive testing) for the scan-build part.

tools/scan-build-py/tests/unit/test_analyze.py

338

You are right. The testing infra in scan-build-py is not right anyway (uses nosetests). However, this should be a new patch as you've mentioned earlier.

[gerazo]

tools/scan-build-py/libscanbuild/analyze.py

146

The reason for the previous is that we need to count the occurence number ofdifferent mappings only let those pass through which don't have multiple variations.

190

Finally, I came to the conclusion that mkdtemp would not be better than the current solution. In order to find our created dir by other threads, we need a designated name. Suffixing it by generated name would further complicate things as we need not to allow multiple concurrent runs here. The current solution is more robust from this point of view.

243

I've checked it through. The only place for an early exit now would be before the else. The 1st and 2nd ifs are in fact non-orthogonal.

255

Th previous call for data removal happens because the user asked for a collect run, so we clean data to do a recollection. This second one happens because the user asked for a full recollection and anaylsis run all in one. So here we destroy the temp data for user's convenience. This happens after, not before like previously. The default behavior is to do this when the user uses the tool the easy way (collect and analyze all in one) and we intentionally keep collection data if the user only asks for a collect or an analyze run. So with this, the user can use a collect run's results for multiple analyze runs. This is written in the command line help. I will definitely put comments here to explain.

319

There is an other thing against changing this. Currently the interface here using env variables is used by intercept-build, analyze-build and scan-build tool as well. In order to drop json, we need to change those tools too. It would be a separate patch definitely.

584

Here the folders are created on demand. Because these are created parallel by multiple processes, there is small chance that an other process already created the folder between the isdir check and the makedirs call. This is why the the pass is needed to make it always run correctly. I will add a comment.

590

After several iterations of the code, I find it easier to version control such multiline constructs. If someone changes a data source, it is clear which one (which line) was modified. The succint notation does not allow clean VCS annotations.

[george.karpenkov]

tools/scan-build-py/libscanbuild/analyze.py

45

However, multiple collect phases launched on a system does not make sense

Why not? What about a system with multiple users, where code is in the shared directory? Or even simpler: I've launched a background process, forgot about it, and then launched it again?

In this case, the later one would write over the previous results with the same data.

That is probably fine, I am more worried about racing, where process B would be reading a partially overriden file (not completely sure whether it is possible)

104

Sure, but that separate PR can also include tests.

121

Right, but instead of doing (1) and (2) can we have a separate (maybe hidden from user) param called e.g. ctu_enabled which would explicitly communicate that?

145

In this case, we deliberately leave such functions out to avoid potential problems

We probably want to log it, don't we?

146

ah, OK!

190

OK

244

OK!

319

OK I didn't know that the JSON interface was used by other tools. In that case, ignore my comment.

590

OK. Though you could still use split addition across multiple lines with \

632

OK so opts['ctu'] is a tuple or a named tuple depending on how this function is entered? BTW could you point me to the analyze_cc entry point?

For the purpose of having more uniform code with less cases to care about, do you think we could just use ordinary tuples instead of constructing a named one, since we have to deconstruct an ordinary tuple in any case?

tools/scan-build-py/libscanbuild/arguments.py

376

BTW can we also explicitly add dest='ctu_dir' here, as otherwise I was initially very confused as to where the variable is set.

tools/scan-build-py/libscanbuild/clang.py

168

so the whole toolset will still throw an error later on not having a clang binary.

Of course, but I think that would be easier to debug, and the error would mean that Clang is not available, not that CTU is not working.

[xazax.hun]

• @gerazo addressed some review comments in scan-build-py.

[george.karpenkov]

Python part looks good to me. I don't know whether @dcoughlin or @NoQ would want to insert additional comments on C++ parts.

[gerazo]

tools/scan-build-py/libscanbuild/analyze.py

45

I see your point. In order to create the multiple user scenario you've mentioned, those users need to give the exact same output folders for their jobs. Our original bet was that our users are not doing this as the scan-build tool itself is also cannot be used this way. Still the process left there is something to consider. I will plan some kind of locking mechanism to avoid situations like this.

632

Using a NamedTuple improves readability of the code a lot with less comments. It is unfortunate that serializing it is not solved by Python. I think moving this code to the entry point would make the whole thing much nicer. The entry point is at analyze_compiler_wrapper

tools/scan-build-py/libscanbuild/arguments.py

376

Yes, of course.

[xazax.hun]

• Further improvements to python script part.

[george.karpenkov]

tools/scan-build-py/libscanbuild/report.py

257

Minor nitpicking: type comments are semi-standardized with Sphinx-style auto-generated documentation, and should be a part of the docstring.

[george.karpenkov]

I've tried using the patch, and I got blocked at the following: CTU options are only exposed when one goes through analyze-build frontend, which requires compile_commands.json to be present. I've used libear to generate compile_commands.json, but the generated JSON does not contain the command field, which causes @require before run to die (also, due to the passing style this error was unnecessarily difficult to debug).
So could you write a short documentation somewhere how all pieces fit together? What entry point should be used, what should people do who don't have a build system-generated compile_commands.jsonetc. etc.

[dcoughlin]

Some comments on the C++ inline.

include/clang/AST/ASTContext.h

82 ↗

(On Diff #126543)

Is this forward declaration needed?

include/clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h

63

I don't think CrossTranslationUnitContext belongs in ExprEngine (it doesn't really have much to do with transfer functions and graph construction.

Can you move it to AnalysisDeclContextManager instead?

Also, when you move it to AnalysisManager can you make it a pointer that is NULL when naive cross-translation support is not enabled? This will make it more clear that the cross-translation unit support will not always be available.

lib/StaticAnalyzer/Core/AnalyzerOptions.cpp

400

Can you also add an analyzer option that is something like 'enable-naive-cross-translation-unit-analysis' and defaults to false?

I'd like to avoid using the presence of 'ctu-dir' as an indication that the analyzer should use the naive CTU analysis. This way when if add a less naive CTU analysis we'll be able to the CTUDir for analysis artifacts (such as summaries) for the less naive CTU analysis as well.

lib/StaticAnalyzer/Core/CallEvent.cpp

379

This downcast is an indication that the CTUContext is living in the wrong class.

386

Can this logic be moved to AnalysisDeclContext->getBody()?

CallEvent::getRuntimeDefinition() is really all about modeling function dispatch at run time. It seems odd to have the cross-translation-unit loading (which is about compiler book-keeping rather than semantics) here.

396

I don't think it makes sense to diagnose index errors here.

Doing it when during analysis means that, for example, the parse error could be emitted or not emitted depending on whether the analyzer thinks a particular call site is reached.

It would be better to validate/parse the index before starting analysis rather than during analysis itself.

lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp

199

There is no need for AnalysisConsumer to take both a CompilerInstance and a Preprocessor. You can just call getPreprocessor() to get the preprocessor from the CompilerInstance

[gerazo]

In D30691#954740, @george.karpenkov wrote:

I've tried using the patch, and I got blocked at the following: CTU options are only exposed when one goes through analyze-build frontend, which requires compile_commands.json to be present. I've used libear to generate compile_commands.json, but the generated JSON does not contain the command field, which causes @require before run to die (also, due to the passing style this error was unnecessarily difficult to debug).
So could you write a short documentation somewhere how all pieces fit together? What entry point should be used, what should people do who don't have a build system-generated compile_commands.jsonetc. etc.

Basically this patch does not change the way scan-build-py is working. So you can either create a compile_commands.json using intercept-build and than use analyze-build to use the result. Or you can do the two together using scan-build. We only offer the CTU functionality in analyze-build, because CTU needs multiple runs anyway, so on the spot build action capture and analyze is not possible with CTU. The general usage of scan-build-py is written in clang/tools/scan-build-py/README.md

[xazax.hun]

lib/StaticAnalyzer/Core/CallEvent.cpp

386

I just tried that and unfortunately, that introduces cyclic dependencies.
CrossTU depends on Frontend. Frontend depends on Sema. Sema depends on Analysis. Making Analysis depending on CrossTU introduces the cycle.

396

While I agree, right now this validation is not the part of the analyzer but the responsibility of the "driver" script for example CodeChecker. It is useful to have this diagnostics to catch bugs in the driver.

[xazax.hun]

• Address some review comments
• Rebased on ToT

[xazax.hun]

lib/StaticAnalyzer/Core/AnalyzerOptions.cpp

407

This option might not be the most readable but this way experimental is a prefix. Do you prefer this way or something like enable-experimental-naive-ctu-analysis?

[NoQ]

Had a fresh look on the C++ part, it is super clean now, i'm very impressed :)

lib/StaticAnalyzer/Core/CallEvent.cpp

373–394

*Humbly suggests to refactor whatever we need here into SubEngine's virtual method(s).

getAnalysisManager() is already there, so i guess we only need to expose getCrossTranslationUnitContext().

385

I think CallEvent is the last place where i'd prefer to hardcode this filename. Maybe hardcode it in CrossTranslationUnitContext or get from AnalyzerOptions? (the former, i guess, because i doubt anybody would ever want to change it).

lib/StaticAnalyzer/Core/PathDiagnostic.cpp

418–424

It seems to me that XDL and YDL are exactly the same as XL and YL we've seen at the beginning of the function.

...we still have only one SourceManager, right?

[xazax.hun]

lib/StaticAnalyzer/Core/PathDiagnostic.cpp

418–424

Is this true?
One is the location associated with the PathDiagnostic the other is the location of the Decl associated with the issue. I do not have deep understanding of this part of the code but not sure if these are guaranteed to be the same.

[NoQ]

lib/StaticAnalyzer/Core/PathDiagnostic.cpp

418–424

Whoops, you're totally right, never mind.

Comments might have probably helped me understand that faster.

[xazax.hun]

• Fixed review comments

[xazax.hun]

lib/StaticAnalyzer/Core/PathDiagnostic.cpp

418–424

Sure, comments might help, but I want to keep the changes in this patch focused and minimal, so I prefer to do such modifications in a separate patch.

[nikhgupt]

lib/StaticAnalyzer/Core/PathDiagnostic.cpp

395

getName could yield incorrect results if two files in the project have the same name. This might break the assert for PathDiagnostics 'total ordering' and 'uniqueness'.
Maybe replacing FileEntry's getName with FullSourceLoc's getFileID could resolve this.

[george.karpenkov]

Python code looks OK to me, I have one last request: could we have a small documentation how the whole thing is supposed work in integration, preferably on an available open-source project any reader could check out?
I am asking because I have actually tried and failed to launch this CTU patch on a project I was analyzing.

[gerazo]

tools/scan-build-py/libscanbuild/analyze.py

718

Scheduled to be done.

tools/scan-build-py/libscanbuild/report.py

270

After careful investigation, I have to say, it would be very hard to tell that we've done this right in the current setup. Unlike the the rest of clang, ASTImporter.cpp is not a strong part of the system. It has a lot of ongoing fixes and probably more problems (missing CXX functionality) on the way. This is the part which makes CTU less reliable than clang generally. In order to elegantly survive a problem of this unit, we need to leave the other things intact and fix ASTImporter instead (this is an ongoing effort). Until then, this fix seems good enough.

[xazax.hun]

• Rebased to current ToT
• Fixed a problem that the scan-build-py used an old version of the ctu configuration option
• Added a short guide how to use CTU

[xazax.hun]

In D30691#1003514, @george.karpenkov wrote:

Python code looks OK to me, I have one last request: could we have a small documentation how the whole thing is supposed work in integration, preferably on an available open-source project any reader could check out?
I am asking because I have actually tried and failed to launch this CTU patch on a project I was analyzing.

We added the documentation. Could you recheck? Thanks in advance!

lib/StaticAnalyzer/Core/PathDiagnostic.cpp

395

Thank you, this is a known problem that we plan to address in a follow-up patch.

[dcoughlin]

Thanks Gabor, this looks good to me. Please commit!

[a.sidorin]

The changes were reverted: http://llvm.org/viewvc/llvm-project?rev=326432&view=rev
Gabor, could you take a look?

[xazax.hun]

@ilya-biryukov

Could you please provide some more details where the cyclic dependency is? I cannot reproduce the problem and usually cmake fails when there is a cyclic dependency and you are building shared libraries.

[xazax.hun]

Resubmitted in https://reviews.llvm.org/rL326439

Phabricator did not display the mailing list conversation. The point is, the circular dependency does not exist in the upstream version of clang. The reason is that CMake does not track the header includes as dependencies. There might be some layering violations with the header includes but those are independent of this patch and need to be fixed separately.

[NoQ]

Just noticed: getRuntimeDefinition() has a lot of overrides in CallEvent sub-classes, and there paths that don't defer to AnyFunctionCall::getRuntimeDefinition(), eg., CXXInstanceCall::getRuntimeDefinition() => if (MD->isVirtual()) .... Which means that for some calls we aren't even trying to make a CTU lookup.

[dkrupp]

Which means that for some calls we aren't even trying to make a CTU lookup.

Thanks @NoQ, we will take a look at it!

[martong]

@NoQ , @dkrupp

CallEvent::getRuntimeDefinition is overwritten in

• AnyFunctionCall
• CXXInstanceCall
• CXXMemberCall
• CXXDestructorCall
• ObjCMethodCall

AnyFunctionCall handles the CTU logic.
CXXInstanceCall calls into AnyFunctionCall if the function is not virtual.
If the function is virtual then we try to find the Decl of it via the dynamic type info.
At this point, we could get the definition of that function via the CTU logic, indeed.
This is something we should implement in the future.

However, it seems like this is the only case (not considering ObjC).
CXXMemberCall calls back to AnyFunctionCall or to CXXInstanceCall.
CXXDestructorCall does the same.

[martong]

Just added a new entry to our roadmap: https://github.com/Ericsson/clang/issues/435

[NoQ]

Aha, cool, so it's probably just virtual functions.

include/clang/StaticAnalyzer/Core/AnalyzerOptions.h

private:
   Optional<bool> WidenLoops;
 
   /// \sa shouldUnrollLoops
   Optional<bool> UnrollLoops;
 
   /// \sa shouldDisplayNotesAsEvents
   Optional<bool> DisplayNotesAsEvents;
 
+  /// \sa getCTUDir
+  Optional<StringRef> CTUDir;
+
+  /// \sa getCTUIndexName
+  Optional<StringRef> CTUIndexName;
+
+  /// \sa naiveCTUEnabled
+  Optional<bool> NaiveCTU;
+
+
   /// A helper function that retrieves option for a given full-qualified
   /// checker name.
   /// Options for checkers can be specified via 'analyzer-config' command-line
   /// option.
   /// Example:
   /// @code-analyzer-config unix.Malloc:OptionName=CheckerOptionValue @endcode
   /// or @code-analyzer-config unix:OptionName=GroupOptionValue @endcode
   /// for groups of checkers.
public:
   /// Returns true if the bug reporter should transparently treat extra note
   /// diagnostic pieces as event diagnostic pieces. Useful when the diagnostic
   /// consumer doesn't support the extra note pieces.
   ///
   /// This is controlled by the 'extra-notes-as-events' option, which defaults
   /// to false when unset.
   bool shouldDisplayNotesAsEvents();
 
+  /// Returns the directory containing the CTU related files.
+  StringRef getCTUDir();
+
+  /// Returns the name of the file containing the CTU index of functions.
+  StringRef getCTUIndexName();
+
+  /// Returns true when naive cross translation unit analysis is enabled.
+  /// This is an experimental feature to inline functions from another
+  /// translation units.
+  bool naiveCTUEnabled();
+
 public:
   AnalyzerOptions() :
     AnalysisStoreOpt(RegionStoreModel),
     AnalysisConstraintsOpt(RangeConstraintsModel),
     AnalysisDiagOpt(PD_HTML),
     AnalysisPurgeOpt(PurgeStmt),
     DisableAllChecks(0),
     ShowCheckerHelp(0),

include/clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h

 class CXXConstructExpr;
 class CXXDeleteExpr;
 class CXXNewExpr;
 class CXXTemporaryObjectExpr;
 class CXXThisExpr;
 class MaterializeTemporaryExpr;
 class ObjCAtSynchronizedStmt;
 class ObjCForCollectionStmt;
-  
+namespace cross_tu {
+class CrossTranslationUnitContext;
+}
+  
 namespace ento {
 
 class AnalysisManager;
 class CallEvent;
 class CXXConstructorCall;
 
 class ExprEngine : public SubEngine {
 public:
   /// The modes of inlining, which override the default analysis-wide settings.
   enum InliningModes {
     /// Follow the default settings for inlining callees.
     Inline_Regular = 0,
     /// Do minimal inlining of callees.
     Inline_Minimal = 0x1
   };
 
 private:
+  cross_tu::CrossTranslationUnitContext &CTU;
+
   AnalysisManager &AMgr;
   
   AnalysisDeclContextManager &AnalysisDeclContexts;
 
   CoreEngine Engine;
 
   /// G - the simulation graph.
   ExplodedGraph& G;
private:
   /// The functions which have been analyzed through inlining. This is owned by
   /// AnalysisConsumer. It can be null.
   SetOfConstDecls *VisitedCallees;
 
   /// The flag, which specifies the mode of inlining for the engine.
   InliningModes HowToInline;
 
 public:
-  ExprEngine(AnalysisManager &mgr, bool gcEnabled,
-             SetOfConstDecls *VisitedCalleesIn,
-             FunctionSummariesTy *FS,
-             InliningModes HowToInlineIn);
+  ExprEngine(cross_tu::CrossTranslationUnitContext &CTU, AnalysisManager &mgr,
+             bool gcEnabled, SetOfConstDecls *VisitedCalleesIn,
+             FunctionSummariesTy *FS, InliningModes HowToInlineIn);
 
   ~ExprEngine() override;
 
   /// Returns true if there is still simulation state on the worklist.
   bool ExecuteWorkList(const LocationContext *L, unsigned Steps = 150000) {
     return Engine.ExecuteWorkList(L, Steps, nullptr);
   }
 
public:
   CheckerManager &getCheckerManager() const {
     return *AMgr.getCheckerManager();
   }
 
   SValBuilder &getSValBuilder() { return svalBuilder; }
 
   BugReporter& getBugReporter() { return BR; }
 
+  cross_tu::CrossTranslationUnitContext *getCrossTranslationUnitContext() {
+    return &CTU;
+  }
+
   const NodeBuilderContext &getBuilderContext() {
     assert(currBldrCtx);
     return *currBldrCtx;
   }
 
   bool isObjCGCEnabled() { return ObjCGCEnabled; }
 
   const Stmt *getStmt() const;

include/clang/StaticAnalyzer/Core/PathSensitive/SubEngine.h

 
 namespace clang {
 
 class CFGBlock;
 class CFGElement;
 class LocationContext;
 class Stmt;
 
+namespace cross_tu {
+class CrossTranslationUnitContext;
+}
+
 namespace ento {
   
 struct NodeBuilderContext;
 class AnalysisManager;
 class ExplodedNodeSet;
 class ExplodedNode;
 class ProgramState;
 class ProgramStateManager;
class SubEngine {
   virtual void anchor();
 public:
   virtual ~SubEngine() {}
 
   virtual ProgramStateRef getInitialState(const LocationContext *InitLoc) = 0;
 
   virtual AnalysisManager &getAnalysisManager() = 0;
 
+  virtual cross_tu::CrossTranslationUnitContext *
+  getCrossTranslationUnitContext() = 0;
+
   virtual ProgramStateManager &getStateManager() = 0;
 
   /// Called by CoreEngine. Used to generate new successor
   /// nodes by processing the 'effects' of a block-level statement.
   virtual void processCFGElement(const CFGElement E, ExplodedNode* Pred,
                                  unsigned StmtIdx, NodeBuilderContext *Ctx)=0;
 
   /// Called by CoreEngine when it starts processing a CFGBlock.  The

lib/StaticAnalyzer/Core/AnalyzerOptions.cpp

 }
 
 bool AnalyzerOptions::shouldDisplayNotesAsEvents() {
   if (!DisplayNotesAsEvents.hasValue())
     DisplayNotesAsEvents =
         getBooleanOption("notes-as-events", /*Default=*/false);
   return DisplayNotesAsEvents.getValue();
 }
+
+StringRef AnalyzerOptions::getCTUDir() {
+  if (!CTUDir.hasValue()) {
+    CTUDir = getOptionAsString("ctu-dir", "");
+    if (!llvm::sys::fs::is_directory(*CTUDir))
+      CTUDir = "";
+  }
+  return CTUDir.getValue();
+}
+
+bool AnalyzerOptions::naiveCTUEnabled() {
+  if (!NaiveCTU.hasValue()) {
+    NaiveCTU = getBooleanOption("experimental-enable-naive-ctu-analysis",
+                                /*Default=*/false);
+  }
+  return NaiveCTU.getValue();
+}
+
+StringRef AnalyzerOptions::getCTUIndexName() {
+  if (!CTUIndexName.hasValue())
+    CTUIndexName = getOptionAsString("ctu-index-name", "externalFnMap.txt");
+  return CTUIndexName.getValue();
+}

lib/StaticAnalyzer/Core/CMakeLists.txt

add_clang_library(clangStaticAnalyzerCore
   SymbolManager.cpp
   Z3ConstraintManager.cpp
 
   LINK_LIBS
   clangAST
   clangASTMatchers
   clangAnalysis
   clangBasic
+  clangCrossTU
   clangLex
   clangRewrite
   ${Z3_LINK_FILES}
   )
 
 if(CLANG_ANALYZER_WITH_Z3)
   target_include_directories(clangStaticAnalyzerCore SYSTEM
     PRIVATE
     ${Z3_INCLUDE_DIR}
     )
 endif()

lib/StaticAnalyzer/Core/CallEvent.cpp

 /// sensitive instances of different kinds of function and method calls
 /// (C, C++, and Objective-C).
 //
 //===----------------------------------------------------------------------===//
 
 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
 #include "clang/AST/ParentMap.h"
 #include "clang/Analysis/ProgramPoint.h"
+#include "clang/CrossTU/CrossTranslationUnit.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/DynamicTypeMap.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Support/Debug.h"
 
 #define DEBUG_TYPE "static-analyzer-call-event"
DEBUG({
                        << "\n";
     });
     if (Body) {
       const Decl* Decl = AD->getDecl();
       return RuntimeDefinition(Decl);
     }
   }
 
+  SubEngine *Engine = getState()->getStateManager().getOwningEngine();
+  AnalyzerOptions &Opts = Engine->getAnalysisManager().options;
+
+  // Try to get CTU definition only if CTUDir is provided.
+  if (!Opts.naiveCTUEnabled())
+    return RuntimeDefinition();
+
+  cross_tu::CrossTranslationUnitContext &CTUCtx =
+      *Engine->getCrossTranslationUnitContext();
+  llvm::Expected<const FunctionDecl *> CTUDeclOrError =
+      CTUCtx.getCrossTUDefinition(FD, Opts.getCTUDir(), Opts.getCTUIndexName());
+
+  if (!CTUDeclOrError) {
+    handleAllErrors(CTUDeclOrError.takeError(),
+                    [&](const cross_tu::IndexError &IE) {
+                      CTUCtx.emitCrossTUDiagnostics(IE);
+                    });
     return RuntimeDefinition();
   }
 
+  return RuntimeDefinition(*CTUDeclOrError);
+}
+
 void AnyFunctionCall::getInitialStackFrameContents(
                                         const StackFrameContext *CalleeCtx,
                                         BindingsTy &Bindings) const {
   const FunctionDecl *D = cast<FunctionDecl>(CalleeCtx->getDecl());
   SValBuilder &SVB = getState()->getStateManager().getSValBuilder();
   addParameterValuesToBindings(CalleeCtx, Bindings, SVB, *this,
                                D->parameters());
 }
 

lib/StaticAnalyzer/Core/ExprEngine.cpp

 #include "clang/AST/CharUnits.h"
 #include "clang/AST/ParentMap.h"
 #include "clang/Analysis/CFGStmtMap.h"
 #include "clang/AST/StmtCXX.h"
 #include "clang/AST/StmtObjC.h"
 #include "clang/Basic/Builtins.h"
 #include "clang/Basic/PrettyStackTrace.h"
 #include "clang/Basic/SourceManager.h"
+#include "clang/CrossTU/CrossTranslationUnit.h"
 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/LoopWidening.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/LoopUnrolling.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/SaveAndRestore.h"
REGISTER_TRAIT_WITH_PROGRAMSTATE(InitializedTemporariesSet,
                                  llvm::ImmutableSet<CXXBindTemporaryContext>)
 
 //===----------------------------------------------------------------------===//
 // Engine construction and deletion.
 //===----------------------------------------------------------------------===//
 
 static const char* TagProviderName = "ExprEngine";
 
-ExprEngine::ExprEngine(AnalysisManager &mgr, bool gcEnabled,
+ExprEngine::ExprEngine(cross_tu::CrossTranslationUnitContext &CTU,
+                       AnalysisManager &mgr, bool gcEnabled,
                        SetOfConstDecls *VisitedCalleesIn,
-                       FunctionSummariesTy *FS,
-                       InliningModes HowToInlineIn)
-  : AMgr(mgr),
+                       FunctionSummariesTy *FS, InliningModes HowToInlineIn)
+    : CTU(CTU), AMgr(mgr),
       AnalysisDeclContexts(mgr.getAnalysisDeclContextManager()),
-    Engine(*this, FS),
-    G(Engine.getGraph()),
+      Engine(*this, FS), G(Engine.getGraph()),
       StateMgr(getContext(), mgr.getStoreManagerCreator(),
-             mgr.getConstraintManagerCreator(), G.getAllocator(),
-             this),
+               mgr.getConstraintManagerCreator(), G.getAllocator(), this),
       SymMgr(StateMgr.getSymbolManager()),
-    svalBuilder(StateMgr.getSValBuilder()),
-    currStmtIdx(0), currBldrCtx(nullptr),
-    ObjCNoRet(mgr.getASTContext()),
+      svalBuilder(StateMgr.getSValBuilder()), currStmtIdx(0),
+      currBldrCtx(nullptr), ObjCNoRet(mgr.getASTContext()),
       ObjCGCEnabled(gcEnabled), BR(mgr, *this),
-    VisitedCallees(VisitedCalleesIn),
-    HowToInline(HowToInlineIn)
-{
+      VisitedCallees(VisitedCalleesIn), HowToInline(HowToInlineIn) {
   unsigned TrimInterval = mgr.options.getGraphTrimInterval();
   if (TrimInterval != 0) {
     // Enable eager node reclaimation when constructing the ExplodedGraph.
     G.enableNodeReclamation(TrimInterval);
   }
 }
 
 ExprEngine::~ExprEngine() {

lib/StaticAnalyzer/Core/PathDiagnostic.cpp

for ( ; X_I != X_end && Y_I != Y_end; ++X_I, ++Y_I) {
     Optional<bool> b = comparePiece(**X_I, **Y_I);
     if (b.hasValue())
       return b.getValue();
   }
 
   return None;
 }
 
+static bool compareCrossTUSourceLocs(FullSourceLoc XL, FullSourceLoc YL) {
+  std::pair<FileID, unsigned> XOffs = XL.getDecomposedLoc();
+  std::pair<FileID, unsigned> YOffs = YL.getDecomposedLoc();
+  const SourceManager &SM = XL.getManager();
+  std::pair<bool, bool> InSameTU = SM.isInTheSameTranslationUnit(XOffs, YOffs);
+  if (InSameTU.first)
+    return XL.isBeforeInTranslationUnitThan(YL);
+  const FileEntry *XFE = SM.getFileEntryForID(XL.getFileID());
+  const FileEntry *YFE = SM.getFileEntryForID(YL.getFileID());
+  if (!XFE || !YFE)
+    return XFE && !YFE;
+  return XFE->getName() < YFE->getName();
+}
+
 static bool compare(const PathDiagnostic &X, const PathDiagnostic &Y) {
   FullSourceLoc XL = X.getLocation().asLocation();
   FullSourceLoc YL = Y.getLocation().asLocation();
   if (XL != YL)
-    return XL.isBeforeInTranslationUnitThan(YL);
+    return compareCrossTUSourceLocs(XL, YL);
   if (X.getBugType() != Y.getBugType())
     return X.getBugType() < Y.getBugType();
   if (X.getCategory() != Y.getCategory())
     return X.getCategory() < Y.getCategory();
   if (X.getVerboseDescription() != Y.getVerboseDescription())
     return X.getVerboseDescription() < Y.getVerboseDescription();
   if (X.getShortDescription() != Y.getShortDescription())
     return X.getShortDescription() < Y.getShortDescription();
   if (X.getDeclWithIssue() != Y.getDeclWithIssue()) {
     const Decl *XD = X.getDeclWithIssue();
     if (!XD)
       return true;
     const Decl *YD = Y.getDeclWithIssue();
     if (!YD)
       return false;
     SourceLocation XDL = XD->getLocation();
     SourceLocation YDL = YD->getLocation();
     if (XDL != YDL) {
       const SourceManager &SM = XL.getManager();
-      return SM.isBeforeInTranslationUnit(XDL, YDL);
+      return compareCrossTUSourceLocs(FullSourceLoc(XDL, SM),
+                                      FullSourceLoc(YDL, SM));
     }
   }
   PathDiagnostic::meta_iterator XI = X.meta_begin(), XE = X.meta_end();
   PathDiagnostic::meta_iterator YI = Y.meta_begin(), YE = Y.meta_end();
   if (XE - XI != YE - YI)
     return (XE - XI) < (YE - YI);
   for ( ; XI != XE ; ++XI, ++YI) {
     if (*XI != *YI)
       return (*XI) < (*YI);

lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp

 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Analysis/Analyses/LiveVariables.h"
 #include "clang/Analysis/CFG.h"
 #include "clang/Analysis/CallGraph.h"
 #include "clang/Analysis/CodeInjector.h"
 #include "clang/Basic/SourceManager.h"
+#include "clang/CrossTU/CrossTranslationUnit.h"
 #include "clang/Frontend/CompilerInstance.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/StaticAnalyzer/Checkers/LocalCheckers.h"
 #include "clang/StaticAnalyzer/Core/AnalyzerOptions.h"
 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
 #include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
 #include "clang/StaticAnalyzer/Core/PathDiagnosticConsumers.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
 #include "clang/StaticAnalyzer/Frontend/CheckerRegistration.h"
 #include "llvm/ADT/PostOrderIterator.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Program.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
 #include <memory>
 #include <queue>
 #include <utility>
 
 using namespace clang;
 using namespace ento;
 
 #define DEBUG_TYPE "AnalysisConsumer"
 
 static std::unique_ptr<ExplodedNode::Auditor> CreateUbiViz();
 
 STATISTIC(NumFunctionTopLevel, "The # of functions at top level.");
 STATISTIC(NumFunctionsAnalyzed,

 
 public:
   ASTContext *Ctx;
   const Preprocessor &PP;
   const std::string OutDir;
   AnalyzerOptionsRef Opts;
   ArrayRef<std::string> Plugins;
   CodeInjector *Injector;
+  cross_tu::CrossTranslationUnitContext CTU;
 
   /// \brief Stores the declarations from the local translation unit.
   /// Note, we pre-compute the local declarations at parse time as an
   /// optimization to make sure we do not deserialize everything from disk.
   /// The local declaration to all declarations ratio might be very small when
   /// working with a PCH file.
   SetOfDecls LocalTUDecls;
 
   // Set of PathDiagnosticConsumers.  Owned by AnalysisManager.
   PathDiagnosticConsumers PathConsumers;
 
   StoreManagerCreator CreateStoreMgr;
   ConstraintManagerCreator CreateConstraintMgr;
 
   std::unique_ptr<CheckerManager> checkerMgr;
   std::unique_ptr<AnalysisManager> Mgr;
 
   /// Time the analyzes time of each translation unit.
   static llvm::Timer* TUTotalTimer;
 
   /// The information about analyzed functions shared throughout the
   /// translation unit.
   FunctionSummariesTy FunctionSummaries;
 
-  AnalysisConsumer(const Preprocessor &pp, const std::string &outdir,
+  AnalysisConsumer(CompilerInstance &CI, const std::string &outdir,
                    AnalyzerOptionsRef opts, ArrayRef<std::string> plugins,
                    CodeInjector *injector)
-      : RecVisitorMode(0), RecVisitorBR(nullptr), Ctx(nullptr), PP(pp),
-        OutDir(outdir), Opts(std::move(opts)), Plugins(plugins),
-        Injector(injector) {
+      : RecVisitorMode(0), RecVisitorBR(nullptr), Ctx(nullptr),
+        PP(CI.getPreprocessor()), OutDir(outdir), Opts(std::move(opts)),
+        Plugins(plugins), Injector(injector), CTU(CI) {
     DigestAnalyzerOptions();
     if (Opts->PrintStats) {
       llvm::EnableStatistics(false);
       TUTotalTimer = new llvm::Timer("time", "Analyzer Total Time");
     }
   }
 
   ~AnalysisConsumer() override {

 }
 
 static bool shouldSkipFunction(const Decl *D,
                                const SetOfConstDecls &Visited,
                                const SetOfConstDecls &VisitedAsTopLevel) {
   if (VisitedAsTopLevel.count(D))
     return true;
 
   // We want to re-analyse the functions as top level in the following cases:
   // - The 'init' methods should be reanalyzed because
   //   ObjCNonNilReturnValueChecker assumes that '[super init]' never returns
   //   'nil' and unless we analyze the 'init' functions as top level, we will
   //   not catch errors within defensive code.
   // - We want to reanalyze all ObjC methods as top level to report Retain
   //   Count naming convention errors more aggressively.
   if (isa<ObjCMethodDecl>(D))
     return false;
void AnalysisConsumer::ActionExprEngine(Decl *D, bool ObjCGCEnabled,
   // FIXME: Inter-procedural analysis will need to handle invalid CFGs.
   if (!Mgr->getCFG(D))
     return;
 
   // See if the LiveVariables analysis scales.
   if (!Mgr->getAnalysisDeclContext(D)->getAnalysis<RelaxedLiveVariables>())
     return;
 
-  ExprEngine Eng(*Mgr, ObjCGCEnabled, VisitedCallees, &FunctionSummaries,IMode);
+  ExprEngine Eng(CTU, *Mgr, ObjCGCEnabled, VisitedCallees, &FunctionSummaries,
+                 IMode);
 
   // Set the graph auditor.
   std::unique_ptr<ExplodedNode::Auditor> Auditor;
   if (Mgr->options.visualizeExplodedGraphWithUbiGraph) {
     Auditor = CreateUbiViz();
     ExplodedNode::SetAuditor(Auditor.get());
   }
 

 ento::CreateAnalysisConsumer(CompilerInstance &CI) {
   // Disable the effects of '-Werror' when using the AnalysisConsumer.
   CI.getPreprocessor().getDiagnostics().setWarningsAsErrors(false);
 
   AnalyzerOptionsRef analyzerOpts = CI.getAnalyzerOpts();
   bool hasModelPath = analyzerOpts->Config.count("model-path") > 0;
 
   return llvm::make_unique<AnalysisConsumer>(
-      CI.getPreprocessor(), CI.getFrontendOpts().OutputFile, analyzerOpts,
+      CI, CI.getFrontendOpts().OutputFile, analyzerOpts,
       CI.getFrontendOpts().Plugins,
       hasModelPath ? new ModelInjector(CI) : nullptr);
 }
 
 //===----------------------------------------------------------------------===//
 // Ubigraph Visualization.  FIXME: Move to separate file.
 //===----------------------------------------------------------------------===//
 

lib/StaticAnalyzer/Frontend/CMakeLists.txt

add_clang_library(clangStaticAnalyzerFrontend
   ModelConsumer.cpp
   FrontendActions.cpp
   ModelInjector.cpp
 
   LINK_LIBS
   clangAST
   clangAnalysis
   clangBasic
+  clangCrossTU
   clangFrontend
   clangLex
   clangStaticAnalyzerCheckers
   clangStaticAnalyzerCore
   )

test/Analysis/Inputs/ctu-chain.cpp

+int h_chain(int x) {
+  return x * 2;
+}
+
+namespace chns {
+int chf3(int x);
+
+int chf2(int x) {
+  return chf3(x);
+}
+
+class chcls {
+public:
+  int chf4(int x);
+};
+
+int chcls::chf4(int x) {
+  return x * 3;
+}
+}

test/Analysis/Inputs/ctu-other.cpp

+int callback_to_main(int x);
+int f(int x) {
+  return x - 1;
+}
+
+int g(int x) {
+  return callback_to_main(x) + 1;
+}
+
+int h_chain(int);
+
+int h(int x) {
+  return 2 * h_chain(x);
+}
+
+namespace myns {
+int fns(int x) {
+  return x + 7;
+}
+
+namespace embed_ns {
+int fens(int x) {
+  return x - 3;
+}
+}
+
+class embed_cls {
+public:
+  int fecl(int x) {
+    return x - 7;
+  }
+};
+}
+
+class mycls {
+public:
+  int fcl(int x) {
+    return x + 5;
+  }
+  static int fscl(int x) {
+    return x + 6;
+  }
+
+  class embed_cls2 {
+  public:
+    int fecl2(int x) {
+      return x - 11;
+    }
+  };
+};
+
+namespace chns {
+int chf2(int x);
+
+class chcls {
+public:
+  int chf4(int x);
+};
+
+int chf3(int x) {
+  return chcls().chf4(x);
+}
+
+int chf1(int x) {
+  return chf2(x);
+}
+}

test/Analysis/Inputs/externalFnMap.txt

+c:@N@chns@F@chf1#I# ctu-other.cpp.ast
+c:@N@myns@N@embed_ns@F@fens#I# ctu-other.cpp.ast
+c:@F@g#I# ctu-other.cpp.ast
+c:@S@mycls@F@fscl#I#S ctu-other.cpp.ast
+c:@S@mycls@F@fcl#I# ctu-other.cpp.ast
+c:@N@myns@S@embed_cls@F@fecl#I# ctu-other.cpp.ast
+c:@S@mycls@S@embed_cls2@F@fecl2#I# ctu-other.cpp.ast
+c:@F@f#I# ctu-other.cpp.ast
+c:@N@myns@F@fns#I# ctu-other.cpp.ast
+c:@F@h#I# ctu-other.cpp.ast
+c:@F@h_chain#I# ctu-chain.cpp.ast
+c:@N@chns@S@chcls@F@chf4#I# ctu-chain.cpp.ast
+c:@N@chns@F@chf2#I# ctu-chain.cpp.ast

test/Analysis/ctu-main.cpp

+// RUN: mkdir -p %T/ctudir
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -emit-pch -o %T/ctudir/ctu-other.cpp.ast %S/Inputs/ctu-other.cpp
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -emit-pch -o %T/ctudir/ctu-chain.cpp.ast %S/Inputs/ctu-chain.cpp
+// RUN: cp %S/Inputs/externalFnMap.txt %T/ctudir/
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -fsyntax-only -analyze -analyzer-checker=core,debug.ExprInspection -analyzer-config experimental-enable-naive-ctu-analysis=true -analyzer-config ctu-dir=%T/ctudir -verify %s
+
+void clang_analyzer_eval(int);
+
+int f(int);
+int g(int);
+int h(int);
+
+int callback_to_main(int x) { return x + 1; }
+
+namespace myns {
+int fns(int x);
+
+namespace embed_ns {
+int fens(int x);
+}
+
+class embed_cls {
+public:
+  int fecl(int x);
+};
+}
+
+class mycls {
+public:
+  int fcl(int x);
+  static int fscl(int x);
+
+  class embed_cls2 {
+  public:
+    int fecl2(int x);
+  };
+};
+
+namespace chns {
+int chf1(int x);
+}
+
+int main() {
+  clang_analyzer_eval(f(3) == 2); // expected-warning{{TRUE}}
+  clang_analyzer_eval(f(4) == 3); // expected-warning{{TRUE}}
+  clang_analyzer_eval(f(5) == 3); // expected-warning{{FALSE}}
+  clang_analyzer_eval(g(4) == 6); // expected-warning{{TRUE}}
+  clang_analyzer_eval(h(2) == 8); // expected-warning{{TRUE}}
+
+  clang_analyzer_eval(myns::fns(2) == 9);                   // expected-warning{{TRUE}}
+  clang_analyzer_eval(myns::embed_ns::fens(2) == -1);       // expected-warning{{TRUE}}
+  clang_analyzer_eval(mycls().fcl(1) == 6);                 // expected-warning{{TRUE}}
+  clang_analyzer_eval(mycls::fscl(1) == 7);                 // expected-warning{{TRUE}}
+  clang_analyzer_eval(myns::embed_cls().fecl(1) == -6);     // expected-warning{{TRUE}}
+  clang_analyzer_eval(mycls::embed_cls2().fecl2(0) == -11); // expected-warning{{TRUE}}
+
+  clang_analyzer_eval(chns::chf1(4) == 12); // expected-warning{{TRUE}}
+}

tools/scan-build-py/libscanbuild/__init__.py

 import shlex
 import subprocess
 import sys
 
 ENVIRONMENT_KEY = 'INTERCEPT_BUILD'
 
 Execution = collections.namedtuple('Execution', ['pid', 'cwd', 'cmd'])
 
+CtuConfig = collections.namedtuple('CtuConfig', ['collect', 'analyze', 'dir',
+                                                 'func_map_cmd'])
+
 
 def duplicate_check(method):
     """ Predicate to detect duplicated entries.
 
     Unique hash method can be use to detect duplicates. Entries are
     represented as dictionaries, which has no default hash method.
     This implementation uses a set datatype to store the unique hash values.
 

tools/scan-build-py/libscanbuild/analyze.py

 import json
 import logging
 import multiprocessing
 import tempfile
 import functools
 import subprocess
 import contextlib
 import datetime
+import shutil
+import glob
+from collections import defaultdict
 
 from libscanbuild import command_entry_point, compiler_wrapper, \
-    wrapper_environment, run_build, run_command
+    wrapper_environment, run_build, run_command, CtuConfig
 from libscanbuild.arguments import parse_args_for_scan_build, \
     parse_args_for_analyze_build
 from libscanbuild.intercept import capture
 from libscanbuild.report import document
 from libscanbuild.compilation import split_command, classify_source, \
     compiler_language
-from libscanbuild.clang import get_version, get_arguments
+from libscanbuild.clang import get_version, get_arguments, get_triple_arch
 from libscanbuild.shell import decode
 
 __all__ = ['scan_build', 'analyze_build', 'analyze_compiler_wrapper']
 
 COMPILER_WRAPPER_CC = 'analyze-cc'
 COMPILER_WRAPPER_CXX = 'analyze-c++'
 
+CTU_FUNCTION_MAP_FILENAME = 'externalFnMap.txt'
+CTU_TEMP_FNMAP_FOLDER = 'tmpExternalFnMaps'
+
 
 @command_entry_point
 def scan_build():
     """ Entry point for scan-build command. """
 
     args = parse_args_for_scan_build()
     # will re-assign the report directory as new output
     with report_directory(args.output, args.keep_empty) as args.output:
         # Run against a build command. there are cases, when analyzer run
         # is not required. But we need to set up everything for the
         # wrappers, because 'configure' needs to capture the CC/CXX values
         # for the Makefile.
         if args.intercept_first:
             # Run build command with intercept module.
             exit_code = capture(args)
             # Run the analyzer against the captured commands.
             if need_analyzer(args.build):
-                run_analyzer_parallel(args)
+                govern_analyzer_runs(args)
         else:
             # Run build command and analyzer with compiler wrappers.
             environment = setup_environment(args)
             exit_code = run_build(args.build, env=environment)
         # Cover report generation and bug counting.
         number_of_bugs = document(args)
         # Set exit status as it was requested.
         return number_of_bugs if args.status_bugs else exit_code
 
 
 @command_entry_point
 def analyze_build():
     """ Entry point for analyze-build command. """
 
     args = parse_args_for_analyze_build()
     # will re-assign the report directory as new output
     with report_directory(args.output, args.keep_empty) as args.output:
         # Run the analyzer against a compilation db.
-        run_analyzer_parallel(args)
+        govern_analyzer_runs(args)
         # Cover report generation and bug counting.
         number_of_bugs = document(args)
         # Set exit status as it was requested.
         return number_of_bugs if args.status_bugs else 0
 
 
 def need_analyzer(args):
     """ Check the intent of the build command.
 
     When static analyzer run against project configure step, it should be
     silent and no need to run the analyzer or generate report.
 
     To run `scan-build` against the configure step might be neccessary,
     when compiler wrappers are used. That's the moment when build setup
     check the compiler and capture the location for the build process. """
 
     return len(args) and not re.search('configure|autogen', args[0])
 
 
+def prefix_with(constant, pieces):
+    """ From a sequence create another sequence where every second element
+    is from the original sequence and the odd elements are the prefix.
+
+    eg.: prefix_with(0, [1,2,3]) creates [0, 1, 0, 2, 0, 3] """
+
+    return [elem for piece in pieces for elem in [constant, piece]]
+
+
+def get_ctu_config_from_args(args):
+    """ CTU configuration is created from the chosen phases and dir. """
+
+    return (
+        CtuConfig(collect=args.ctu_phases.collect,
+                  analyze=args.ctu_phases.analyze,
+                  dir=args.ctu_dir,
+                  func_map_cmd=args.func_map_cmd)
+        if hasattr(args, 'ctu_phases') and hasattr(args.ctu_phases, 'dir')
+        else CtuConfig(collect=False, analyze=False, dir='', func_map_cmd=''))
+
+
+def get_ctu_config_from_json(ctu_conf_json):
+    """ CTU configuration is created from the chosen phases and dir. """
+
+    ctu_config = json.loads(ctu_conf_json)
+    # Recover namedtuple from json when coming from analyze-cc or analyze-c++
+    return CtuConfig(collect=ctu_config[0],
+                     analyze=ctu_config[1],
+                     dir=ctu_config[2],
+                     func_map_cmd=ctu_config[3])
+
+
+def create_global_ctu_function_map(func_map_lines):
+    """ Takes iterator of individual function maps and creates a global map
+    keeping only unique names. We leave conflicting names out of CTU.
+
+    :param func_map_lines: Contains the id of a function (mangled name) and
+    the originating source (the corresponding AST file) name.
+    :type func_map_lines: Iterator of str.
+    :returns: Mangled name - AST file pairs.
+    :rtype: List of (str, str) tuples.
+    """
+
+    mangled_to_asts = defaultdict(set)
+
+    for line in func_map_lines:
+        mangled_name, ast_file = line.strip().split(' ', 1)
+        mangled_to_asts[mangled_name].add(ast_file)
+
+    mangled_ast_pairs = []
+
+    for mangled_name, ast_files in mangled_to_asts.items():
+        if len(ast_files) == 1:
+            mangled_ast_pairs.append((mangled_name, next(iter(ast_files))))
+
+    return mangled_ast_pairs
+
+
+def merge_ctu_func_maps(ctudir):
+    """ Merge individual function maps into a global one.
+
+    As the collect phase runs parallel on multiple threads, all compilation
+    units are separately mapped into a temporary file in CTU_TEMP_FNMAP_FOLDER.
+    These function maps contain the mangled names of functions and the source
+    (AST generated from the source) which had them.
+    These files should be merged at the end into a global map file:
+    CTU_FUNCTION_MAP_FILENAME."""
+
+    def generate_func_map_lines(fnmap_dir):
+        """ Iterate over all lines of input files in a determined order. """
+
+        files = glob.glob(os.path.join(fnmap_dir, '*'))
+        files.sort()
+        for filename in files:
+            with open(filename, 'r') as in_file:
+                for line in in_file:
+                    yield line
+
+    def write_global_map(arch, mangled_ast_pairs):
+        """ Write (mangled function name, ast file) pairs into final file. """
+
+        extern_fns_map_file = os.path.join(ctudir, arch,
+                                           CTU_FUNCTION_MAP_FILENAME)
+        with open(extern_fns_map_file, 'w') as out_file:
+            for mangled_name, ast_file in mangled_ast_pairs:
+                out_file.write('%s %s\n' % (mangled_name, ast_file))
+
+    triple_arches = glob.glob(os.path.join(ctudir, '*'))
+    for triple_path in triple_arches:
+        if os.path.isdir(triple_path):
+            triple_arch = os.path.basename(triple_path)
+            fnmap_dir = os.path.join(ctudir, triple_arch,
+                                     CTU_TEMP_FNMAP_FOLDER)
+
+            func_map_lines = generate_func_map_lines(fnmap_dir)
+            mangled_ast_pairs = create_global_ctu_function_map(func_map_lines)
+            write_global_map(triple_arch, mangled_ast_pairs)
+
+            # Remove all temporary files
+            shutil.rmtree(fnmap_dir, ignore_errors=True)
+
+
 def run_analyzer_parallel(args):
     """ Runs the analyzer against the given compilation database. """
 
     def exclude(filename):
         """ Return true when any excluded directory prefix the filename. """
         return any(re.match(r'^' + directory, filename)
                    for directory in args.excludes)
 
     consts = {
         'clang': args.clang,
         'output_dir': args.output,
         'output_format': args.output_format,
         'output_failures': args.output_failures,
         'direct_args': analyzer_params(args),
-        'force_debug': args.force_debug
+        'force_debug': args.force_debug,
+        'ctu': get_ctu_config_from_args(args)
     }
 
     logging.debug('run analyzer against compilation database')
     with open(args.cdb, 'r') as handle:
         generator = (dict(cmd, **consts)
                      for cmd in json.load(handle) if not exclude(cmd['file']))
         # when verbose output requested execute sequentially
         pool = multiprocessing.Pool(1 if args.verbose > 2 else None)
         for current in pool.imap_unordered(run, generator):
             if current is not None:
                 # display error message from the static analyzer
                 for line in current['error_output']:
                     logging.info(line.rstrip())
         pool.close()
         pool.join()
 
 
+def govern_analyzer_runs(args):
+    """ Governs multiple runs in CTU mode or runs once in normal mode. """
+
+    ctu_config = get_ctu_config_from_args(args)
+    # If we do a CTU collect (1st phase) we remove all previous collection
+    # data first.
+    if ctu_config.collect:
+        shutil.rmtree(ctu_config.dir, ignore_errors=True)
+
+    # If the user asked for a collect (1st) and analyze (2nd) phase, we do an
+    # all-in-one run where we deliberately remove collection data before and
+    # also after the run. If the user asks only for a single phase data is
+    # left so multiple analyze runs can use the same data gathered by a single
+    # collection run.
+    if ctu_config.collect and ctu_config.analyze:
+        # CTU strings are coming from args.ctu_dir and func_map_cmd,
+        # so we can leave it empty
+        args.ctu_phases = CtuConfig(collect=True, analyze=False,
+                                    dir='', func_map_cmd='')
+        run_analyzer_parallel(args)
+        merge_ctu_func_maps(ctu_config.dir)
+        args.ctu_phases = CtuConfig(collect=False, analyze=True,
+                                    dir='', func_map_cmd='')
+        run_analyzer_parallel(args)
+        shutil.rmtree(ctu_config.dir, ignore_errors=True)
+    else:
+        # Single runs (collect or analyze) are launched from here.
+        run_analyzer_parallel(args)
+        if ctu_config.collect:
+            merge_ctu_func_maps(ctu_config.dir)
+
+
 def setup_environment(args):
     """ Set up environment for build command to interpose compiler wrapper. """
 
     environment = dict(os.environ)
     environment.update(wrapper_environment(args))
     environment.update({
         'CC': COMPILER_WRAPPER_CC,
         'CXX': COMPILER_WRAPPER_CXX,
         'ANALYZE_BUILD_CLANG': args.clang if need_analyzer(args.build) else '',
         'ANALYZE_BUILD_REPORT_DIR': args.output,
         'ANALYZE_BUILD_REPORT_FORMAT': args.output_format,
         'ANALYZE_BUILD_REPORT_FAILURES': 'yes' if args.output_failures else '',
         'ANALYZE_BUILD_PARAMETERS': ' '.join(analyzer_params(args)),
-        'ANALYZE_BUILD_FORCE_DEBUG': 'yes' if args.force_debug else ''
+        'ANALYZE_BUILD_FORCE_DEBUG': 'yes' if args.force_debug else '',
+        'ANALYZE_BUILD_CTU': json.dumps(get_ctu_config_from_args(args))
     })
     return environment
 
 
 @command_entry_point
 def analyze_compiler_wrapper():
     """ Entry point for `analyze-cc` and `analyze-c++` compiler wrappers. """
 
parameters = {
         'clang': os.getenv('ANALYZE_BUILD_CLANG'),
         'output_dir': os.getenv('ANALYZE_BUILD_REPORT_DIR'),
         'output_format': os.getenv('ANALYZE_BUILD_REPORT_FORMAT'),
         'output_failures': os.getenv('ANALYZE_BUILD_REPORT_FAILURES'),
         'direct_args': os.getenv('ANALYZE_BUILD_PARAMETERS',
                                  '').split(' '),
         'force_debug': os.getenv('ANALYZE_BUILD_FORCE_DEBUG'),
         'directory': execution.cwd,
-        'command': [execution.cmd[0], '-c'] + compilation.flags
+        'command': [execution.cmd[0], '-c'] + compilation.flags,
+        'ctu': get_ctu_config_from_json(os.getenv('ANALYZE_BUILD_CTU'))
     }
     # call static analyzer against the compilation
     for source in compilation.files:
         parameters.update({'file': source})
         logging.debug('analyzer parameters %s', parameters)
         current = run(parameters)
         # display error message from the static analyzer
         if current is not None:
finally:
         if not keep:
             os.rmdir(name)
 
 
 def analyzer_params(args):
     """ A group of command line arguments can mapped to command
     line arguments of the analyzer. This method generates those. """
 
-    def prefix_with(constant, pieces):
-        """ From a sequence create another sequence where every second element
-        is from the original sequence and the odd elements are the prefix.
-
-        eg.: prefix_with(0, [1,2,3]) creates [0, 1, 0, 2, 0, 3] """
-
-        return [elem for piece in pieces for elem in [constant, piece]]
-
     result = []
 
     if args.store_model:
         result.append('-analyzer-store={0}'.format(args.store_model))
     if args.constraints_model:
         result.append('-analyzer-constraints={0}'.format(
             args.constraints_model))
     if args.internal_stats:

 
 @require(['command',  # entry from compilation database
           'directory',  # entry from compilation database
           'file',  # entry from compilation database
           'clang',  # clang executable name (and path)
           'direct_args',  # arguments from command line
           'force_debug',  # kill non debug macros
           'output_dir',  # where generated report files shall go
-          'output_format',  # it's 'plist' or 'html' or both
-          'output_failures'])  # generate crash reports or not
+          'output_format',  # it's 'plist', 'html', both or plist-multi-file
+          'output_failures',  # generate crash reports or not
+          'ctu'])  # ctu control options
 def run(opts):
     """ Entry point to run (or not) static analyzer against a single entry
     of the compilation database.
 
     This complex task is decomposed into smaller methods which are calling
     each other in chain. If the analyzis is not possibe the given method
     just return and break the chain.
 
@require(['clang', 'directory', 'flags', 'direct_args', 'file', 'output_dir',
           'output_format'])
 def run_analyzer(opts, continuation=report_failure):
     """ It assembles the analysis command line and executes it. Capture the
     output of the analysis and returns with it. If failure reports are
     requested, it calls the continuation to generate it. """
 
     def target():
         """ Creates output file name for reports. """
-        if opts['output_format'] in {'plist', 'plist-html'}:
+        if opts['output_format'] in {
+                'plist',
+                'plist-html',
+                'plist-multi-file'}:
             (handle, name) = tempfile.mkstemp(prefix='report-',
                                               suffix='.plist',
                                               dir=opts['output_dir'])
             os.close(handle)
             return name
         return opts['output_dir']
 
     try:
         cwd = opts['directory']
         cmd = get_arguments([opts['clang'], '--analyze'] +
                             opts['direct_args'] + opts['flags'] +
                             [opts['file'], '-o', target()],
                             cwd)
         output = run_command(cmd, cwd=cwd)
         return {'error_output': output, 'exit_code': 0}
     except subprocess.CalledProcessError as ex:
         result = {'error_output': ex.output, 'exit_code': ex.returncode}
         if opts.get('output_failures', False):
             opts.update(result)
             continuation(opts)
         return result
 
 
+def func_map_list_src_to_ast(func_src_list):
+    """ Turns textual function map list with source files into a
+    function map list with ast files. """
+
+    func_ast_list = []
+    for fn_src_txt in func_src_list:
+        mangled_name, path = fn_src_txt.split(" ", 1)
+        # Normalize path on windows as well
+        path = os.path.splitdrive(path)[1]
+        # Make relative path out of absolute
+        path = path[1:] if path[0] == os.sep else path
+        ast_path = os.path.join("ast", path + ".ast")
+        func_ast_list.append(mangled_name + " " + ast_path)
+    return func_ast_list
+
+
+@require(['clang', 'directory', 'flags', 'direct_args', 'file', 'ctu'])
+def ctu_collect_phase(opts):
+    """ Preprocess source by generating all data needed by CTU analysis. """
+
+    def generate_ast(triple_arch):
+        """ Generates ASTs for the current compilation command. """
+
+        args = opts['direct_args'] + opts['flags']
+        ast_joined_path = os.path.join(opts['ctu'].dir, triple_arch, 'ast',
+                                       os.path.realpath(opts['file'])[1:] +
+                                       '.ast')
+        ast_path = os.path.abspath(ast_joined_path)
+        ast_dir = os.path.dirname(ast_path)
+        if not os.path.isdir(ast_dir):
+            try:
+                os.makedirs(ast_dir)
+            except OSError:
+                # In case an other process already created it.
+                pass
+        ast_command = [opts['clang'], '-emit-ast']
+        ast_command.extend(args)
+        ast_command.append('-w')
+        ast_command.append(opts['file'])
+        ast_command.append('-o')
+        ast_command.append(ast_path)
+        logging.debug("Generating AST using '%s'", ast_command)
+        run_command(ast_command, cwd=opts['directory'])
+
+    def map_functions(triple_arch):
+        """ Generate function map file for the current source. """
+
+        args = opts['direct_args'] + opts['flags']
+        funcmap_command = [opts['ctu'].func_map_cmd]
+        funcmap_command.append(opts['file'])
+        funcmap_command.append('--')
+        funcmap_command.extend(args)
+        logging.debug("Generating function map using '%s'", funcmap_command)
+        func_src_list = run_command(funcmap_command, cwd=opts['directory'])
+        func_ast_list = func_map_list_src_to_ast(func_src_list)
+        extern_fns_map_folder = os.path.join(opts['ctu'].dir, triple_arch,
+                                             CTU_TEMP_FNMAP_FOLDER)
+        if not os.path.isdir(extern_fns_map_folder):
+            try:
+                os.makedirs(extern_fns_map_folder)
+            except OSError:
+                # In case an other process already created it.
+                pass
+        if func_ast_list:
+            with tempfile.NamedTemporaryFile(mode='w',
+                                             dir=extern_fns_map_folder,
+                                             delete=False) as out_file:
+                out_file.write("\n".join(func_ast_list) + "\n")
+
+    cwd = opts['directory']
+    cmd = [opts['clang'], '--analyze'] + opts['direct_args'] + opts['flags'] \
+        + [opts['file']]
+    triple_arch = get_triple_arch(cmd, cwd)
+    generate_ast(triple_arch)
+    map_functions(triple_arch)
+
+
+@require(['ctu'])
+def dispatch_ctu(opts, continuation=run_analyzer):
+    """ Execute only one phase of 2 phases of CTU if needed. """
+
+    ctu_config = opts['ctu']
+
+    if ctu_config.collect or ctu_config.analyze:
+        assert ctu_config.collect != ctu_config.analyze
+        if ctu_config.collect:
+            return ctu_collect_phase(opts)
+        if ctu_config.analyze:
+            cwd = opts['directory']
+            cmd = [opts['clang'], '--analyze'] + opts['direct_args'] \
+                + opts['flags'] + [opts['file']]
+            triarch = get_triple_arch(cmd, cwd)
+            ctu_options = ['ctu-dir=' + os.path.join(ctu_config.dir, triarch),
+                           'reanalyze-ctu-visited=true']
+            analyzer_options = prefix_with('-analyzer-config', ctu_options)
+            direct_options = prefix_with('-Xanalyzer', analyzer_options)
+            opts['direct_args'].extend(direct_options)
+
+    return continuation(opts)
+
+
 @require(['flags', 'force_debug'])
-def filter_debug_flags(opts, continuation=run_analyzer):
+def filter_debug_flags(opts, continuation=dispatch_ctu):
     """ Filter out nondebug macros when requested. """
 
     if opts.pop('force_debug'):
         # lazy implementation just append an undefine macro at the end
         opts.update({'flags': opts['flags'] + ['-UNDEBUG']})
 
     return continuation(opts)
 
if received_list:
             return continuation(opts)
         else:
             logging.debug('skip analysis, found not supported arch')
             return None
     else:
         logging.debug('analysis, on default arch')
         return continuation(opts)
 
+
 # To have good results from static analyzer certain compiler options shall be
 # omitted. The compiler flag filtering only affects the static analyzer run.
 #
 # Keys are the option name, value number of options to skip
 IGNORED_FLAGS = {
     '-c': 0,  # compile option will be overwritten
     '-fsyntax-only': 0,  # static analyzer option will be overwritten
     '-o': 1,  # will set up own output file

tools/scan-build-py/libscanbuild/arguments.py

 Validations are mostly calling specific help methods, or mangling values.
 """
 
 import os
 import sys
 import argparse
 import logging
 import tempfile
-from libscanbuild import reconfigure_logging
-from libscanbuild.clang import get_checkers
+from libscanbuild import reconfigure_logging, CtuConfig
+from libscanbuild.clang import get_checkers, is_ctu_capable
 
 __all__ = ['parse_args_for_intercept_build', 'parse_args_for_analyze_build',
            'parse_args_for_scan_build']
 
 
 def parse_args_for_intercept_build():
     """ Parse and validate command-line arguments for intercept-build. """
 
def normalize_args_for_analyze(args, from_build_command):
     # expecting some argument to be present. so, instead of query the args
     # object about the presence of the flag, we fake it here. to make those
     # methods more readable. (it's an arguable choice, took it only for those
     # which have good default value.)
     if from_build_command:
         # add cdb parameter invisibly to make report module working.
         args.cdb = 'compile_commands.json'
 
+    # Make ctu_dir an abspath as it is needed inside clang
+    if not from_build_command and hasattr(args, 'ctu_phases') \
+            and hasattr(args.ctu_phases, 'dir'):
+        args.ctu_dir = os.path.abspath(args.ctu_dir)
+
 
 def validate_args_for_analyze(parser, args, from_build_command):
     """ Command line parsing is done by the argparse module, but semantic
     validation still needs to be done. This method is doing it for
     analyze-build and scan-build commands.
 
     :param parser: The command line parser object.
     :param args: Parsed argument object.
     :param from_build_command: Boolean value tells is the command suppose
     to run the analyzer against a build command or a compilation db.
     :return: No return value, but this call might throw when validation
     fails. """
 
     if args.help_checkers_verbose:
         print_checkers(get_checkers(args.clang, args.plugins))
         parser.exit(status=0)
     elif args.help_checkers:
         print_active_checkers(get_checkers(args.clang, args.plugins))
         parser.exit(status=0)
     elif from_build_command and not args.build:
         parser.error(message='missing build command')
     elif not from_build_command and not os.path.exists(args.cdb):
         parser.error(message='compilation database is missing')
 
+    # If the user wants CTU mode
+    if not from_build_command and hasattr(args, 'ctu_phases') \
+            and hasattr(args.ctu_phases, 'dir'):
+        # If CTU analyze_only, the input directory should exist
+        if args.ctu_phases.analyze and not args.ctu_phases.collect \
+                and not os.path.exists(args.ctu_dir):
+            parser.error(message='missing CTU directory')
+        # Check CTU capability via checking clang-func-mapping
+        if not is_ctu_capable(args.func_map_cmd):
+            parser.error(message="""This version of clang does not support CTU
+            functionality or clang-func-mapping command not found.""")
+
 
 def create_intercept_parser():
     """ Creates a parser for command-line arguments to 'intercept'. """
 
     parser = create_default_parser()
     parser_add_cdb(parser)
 
     parser_add_prefer_wrapper(parser)
def create_analyze_parser(from_build_command):
     format_group.add_argument(
         '--plist-html',
         '-plist-html',
         dest='output_format',
         const='plist-html',
         default='html',
         action='store_const',
         help="""Cause the results as a set of .html and .plist files.""")
-    # TODO: implement '-view '
+    format_group.add_argument(
+        '--plist-multi-file',
+        '-plist-multi-file',
+        dest='output_format',
+        const='plist-multi-file',
+        default='html',
+        action='store_const',
+        help="""Cause the results as a set of .plist files with extra
+        information on related files.""")
 
     advanced = parser.add_argument_group('advanced options')
     advanced.add_argument(
         '--use-analyzer',
         metavar='<path>',
         dest='clang',
         default='clang',
         help="""'%(prog)s' uses the 'clang' executable relative to itself for
def create_analyze_parser(from_build_command):
     plugins.add_argument(
         '--help-checkers-verbose',
         action='store_true',
         help="""Print all available checkers and mark the enabled ones.""")
 
     if from_build_command:
         parser.add_argument(
             dest='build', nargs=argparse.REMAINDER, help="""Command to run.""")
+    else:
+        ctu = parser.add_argument_group('cross translation unit analysis')
+        ctu_mutex_group = ctu.add_mutually_exclusive_group()
+        ctu_mutex_group.add_argument(
+            '--ctu',
+            action='store_const',
+            const=CtuConfig(collect=True, analyze=True,
+                            dir='', func_map_cmd=''),
+            dest='ctu_phases',
+            help="""Perform cross translation unit (ctu) analysis (both collect
+            and analyze phases) using default <ctu-dir> for temporary output.
+            At the end of the analysis, the temporary directory is removed.""")
+        ctu.add_argument(
+            '--ctu-dir',
+            metavar='<ctu-dir>',
+            dest='ctu_dir',
+            default='ctu-dir',
+            help="""Defines the temporary directory used between ctu
+            phases.""")
+        ctu_mutex_group.add_argument(
+            '--ctu-collect-only',
+            action='store_const',
+            const=CtuConfig(collect=True, analyze=False,
+                            dir='', func_map_cmd=''),
+            dest='ctu_phases',
+            help="""Perform only the collect phase of ctu.
+            Keep <ctu-dir> for further use.""")
+        ctu_mutex_group.add_argument(
+            '--ctu-analyze-only',
+            action='store_const',
+            const=CtuConfig(collect=False, analyze=True,
+                            dir='', func_map_cmd=''),
+            dest='ctu_phases',
+            help="""Perform only the analyze phase of ctu. <ctu-dir> should be
+            present and will not be removed after analysis.""")
+        ctu.add_argument(
+            '--use-func-map-cmd',
+            metavar='<path>',
+            dest='func_map_cmd',
+            default='clang-func-mapping',
+            help="""'%(prog)s' uses the 'clang-func-mapping' executable
+            relative to itself for generating function maps for static
+            analysis. One can override this behavior with this option by using
+            the 'clang-func-mapping' packaged with Xcode (on OS X) or from the
+            PATH.""")
     return parser
 
 
 def create_default_parser():
     """ Creates command line parser for all build wrapper commands. """
 
     parser = argparse.ArgumentParser(
         formatter_class=argparse.ArgumentDefaultsHelpFormatter)

tools/scan-build-py/libscanbuild/clang.py

 # -*- coding: utf-8 -*-
 #                     The LLVM Compiler Infrastructure
 #
 # This file is distributed under the University of Illinois Open Source
 # License. See LICENSE.TXT for details.
 """ This module is responsible for the Clang executable.
 
 Since Clang command line interface is so rich, but this project is using only
 a subset of that, it makes sense to create a function specific wrapper. """
 
+import subprocess
 import re
 from libscanbuild import run_command
 from libscanbuild.shell import decode
 
-__all__ = ['get_version', 'get_arguments', 'get_checkers']
+__all__ = ['get_version', 'get_arguments', 'get_checkers', 'is_ctu_capable',
+           'get_triple_arch']
 
 # regex for activated checker
 ACTIVE_CHECKER_PATTERN = re.compile(r'^-analyzer-checker=(.*)$')
 
 
 def get_version(clang):
     """ Returns the compiler version as string.
 
def get_checkers(clang, plugins):
     checkers = {
         name: (description, is_active_checker(name))
         for name, description in parse_checkers(lines)
     }
     if not checkers:
         raise Exception('Could not query Clang for available checkers.')
 
     return checkers
+
+
+def is_ctu_capable(func_map_cmd):
+    """ Detects if the current (or given) clang and function mapping
+    executables are CTU compatible. """
+
+    try:
+        run_command([func_map_cmd, '-version'])
+    except (OSError, subprocess.CalledProcessError):
+        return False
+    return True
+
+
+def get_triple_arch(command, cwd):
+    """Returns the architecture part of the target triple for the given
+    compilation command. """
+
+    cmd = get_arguments(command, cwd)
+    try:
+        separator = cmd.index("-triple")
+        return cmd[separator + 1]
+    except (IndexError, ValueError):
+        return ""

tools/scan-build-py/libscanbuild/report.py

 # -*- coding: utf-8 -*-
 #                     The LLVM Compiler Infrastructure
 #
 # This file is distributed under the University of Illinois Open Source
 # License. See LICENSE.TXT for details.
 """ This module is responsible to generate 'index.html' for the report.
 
 The input for this step is the output directory, where individual reports
 could be found. It parses those reports and generates 'index.html'. """
 
 import re
 import os
 import os.path
 import sys
 import shutil
-import itertools
 import plistlib
 import glob
 import json
 import logging
 import datetime
 from libscanbuild import duplicate_check
 from libscanbuild.clang import get_version
 
def read_crashes(output_dir):
     """ Generate a unique sequence of crashes from given output directory. """
 
     return (parse_crash(filename)
             for filename in glob.iglob(os.path.join(output_dir, 'failures',
                                                     '*.info.txt')))
 
 
 def read_bugs(output_dir, html):
+    # type: (str, bool) -> Generator[Dict[str, Any], None, None]
     """ Generate a unique sequence of bugs from given output directory.
 
     Duplicates can be in a project if the same module was compiled multiple
     times with different compiler options. These would be better to show in
     the final report (cover) only once. """
 
-    parser = parse_bug_html if html else parse_bug_plist
-    pattern = '*.html' if html else '*.plist'
+    def empty(file_name):
+        return os.stat(file_name).st_size == 0
 
     duplicate = duplicate_check(
         lambda bug: '{bug_line}.{bug_path_length}:{bug_file}'.format(**bug))
 
-    bugs = itertools.chain.from_iterable(
-        # parser creates a bug generator not the bug itself
-        parser(filename)
-        for filename in glob.iglob(os.path.join(output_dir, pattern)))
-
-    return (bug for bug in bugs if not duplicate(bug))
+    # get the right parser for the job.
+    parser = parse_bug_html if html else parse_bug_plist
+    # get the input files, which are not empty.
+    pattern = os.path.join(output_dir, '*.html' if html else '*.plist')
+    bug_files = (file for file in glob.iglob(pattern) if not empty(file))
+
+    for bug_file in bug_files:
+        for bug in parser(bug_file):
+            if not duplicate(bug):
+                yield bug
 
 
 def parse_bug_plist(filename):
     """ Returns the generator of bugs from a single .plist file. """
 
     content = plistlib.readPlist(filename)
     files = content.get('files')
     for bug in content.get('diagnostics', []):

tools/scan-build-py/tests/unit/test_analyze.py

 # -*- coding: utf-8 -*-
 #                     The LLVM Compiler Infrastructure
 #
 # This file is distributed under the University of Illinois Open Source
 # License. See LICENSE.TXT for details.
 
-import libear
-import libscanbuild.analyze as sut
 import unittest
 import re
 import os
 import os.path
+import libear
+import libscanbuild.analyze as sut
 
 
 class ReportDirectoryTest(unittest.TestCase):
 
     # Test that successive report directory names ascend in lexicographic
     # order. This is required so that report directories from two runs of
     # scan-build can be easily matched up to compare results.
     def test_directory_name_comparison(self):
def test_method_with_expecteds(self):
         self.assertRaises(KeyError, method_with_expecteds, dict())
         self.assertRaises(KeyError, method_with_expecteds, {})
         self.assertRaises(KeyError, method_with_expecteds, {'this': 2})
         self.assertRaises(KeyError, method_with_expecteds, {'that': 3})
         self.assertEqual(method_with_expecteds({'this': 0, 'that': 3}), 0)
 
     def test_method_exception_not_caught(self):
         self.assertRaises(Exception, method_exception_from_inside, dict())
+
+
+class PrefixWithTest(unittest.TestCase):
+
+    def test_gives_empty_on_empty(self):
+        res = sut.prefix_with(0, [])
+        self.assertFalse(res)
+
+    def test_interleaves_prefix(self):
+        res = sut.prefix_with(0, [1, 2, 3])
+        self.assertListEqual([0, 1, 0, 2, 0, 3], res)
+
+
+class MergeCtuMapTest(unittest.TestCase):
+
+    def test_no_map_gives_empty(self):
+        pairs = sut.create_global_ctu_function_map([])
+        self.assertFalse(pairs)
+
+    def test_multiple_maps_merged(self):
+        concat_map = ['c:@F@fun1#I# ast/fun1.c.ast',
+                      'c:@F@fun2#I# ast/fun2.c.ast',
+                      'c:@F@fun3#I# ast/fun3.c.ast']
+        pairs = sut.create_global_ctu_function_map(concat_map)
+        self.assertTrue(('c:@F@fun1#I#', 'ast/fun1.c.ast') in pairs)
+        self.assertTrue(('c:@F@fun2#I#', 'ast/fun2.c.ast') in pairs)
+        self.assertTrue(('c:@F@fun3#I#', 'ast/fun3.c.ast') in pairs)
+        self.assertEqual(3, len(pairs))
+
+    def test_not_unique_func_left_out(self):
+        concat_map = ['c:@F@fun1#I# ast/fun1.c.ast',
+                      'c:@F@fun2#I# ast/fun2.c.ast',
+                      'c:@F@fun1#I# ast/fun7.c.ast']
+        pairs = sut.create_global_ctu_function_map(concat_map)
+        self.assertFalse(('c:@F@fun1#I#', 'ast/fun1.c.ast') in pairs)
+        self.assertFalse(('c:@F@fun1#I#', 'ast/fun7.c.ast') in pairs)
+        self.assertTrue(('c:@F@fun2#I#', 'ast/fun2.c.ast') in pairs)
+        self.assertEqual(1, len(pairs))
+
+    def test_duplicates_are_kept(self):
+        concat_map = ['c:@F@fun1#I# ast/fun1.c.ast',
+                      'c:@F@fun2#I# ast/fun2.c.ast',
+                      'c:@F@fun1#I# ast/fun1.c.ast']
+        pairs = sut.create_global_ctu_function_map(concat_map)
+        self.assertTrue(('c:@F@fun1#I#', 'ast/fun1.c.ast') in pairs)
+        self.assertTrue(('c:@F@fun2#I#', 'ast/fun2.c.ast') in pairs)
+        self.assertEqual(2, len(pairs))
+
+    def test_space_handled_in_source(self):
+        concat_map = ['c:@F@fun1#I# ast/f un.c.ast']
+        pairs = sut.create_global_ctu_function_map(concat_map)
+        self.assertTrue(('c:@F@fun1#I#', 'ast/f un.c.ast') in pairs)
+        self.assertEqual(1, len(pairs))
+
+
+class FuncMapSrcToAstTest(unittest.TestCase):
+
+    def test_empty_gives_empty(self):
+        fun_ast_lst = sut.func_map_list_src_to_ast([])
+        self.assertFalse(fun_ast_lst)
+
+    def test_sources_to_asts(self):
+        fun_src_lst = ['c:@F@f1#I# ' + os.path.join(os.sep + 'path', 'f1.c'),
+                       'c:@F@f2#I# ' + os.path.join(os.sep + 'path', 'f2.c')]
+        fun_ast_lst = sut.func_map_list_src_to_ast(fun_src_lst)
+        self.assertTrue('c:@F@f1#I# ' +
+                        os.path.join('ast', 'path', 'f1.c.ast')
+                        in fun_ast_lst)
+        self.assertTrue('c:@F@f2#I# ' +
+                        os.path.join('ast', 'path', 'f2.c.ast')
+                        in fun_ast_lst)
+        self.assertEqual(2, len(fun_ast_lst))
+
+    def test_spaces_handled(self):
+        fun_src_lst = ['c:@F@f1#I# ' + os.path.join(os.sep + 'path', 'f 1.c')]
+        fun_ast_lst = sut.func_map_list_src_to_ast(fun_src_lst)
+        self.assertTrue('c:@F@f1#I# ' +
+                        os.path.join('ast', 'path', 'f 1.c.ast')
+                        in fun_ast_lst)
+        self.assertEqual(1, len(fun_ast_lst))

tools/scan-build-py/tests/unit/test_clang.py

def test_parse_checkers(self):
             '  checker.one       Checker One description',
             '  checker.two',
             '                    Checker Two description']
         result = dict(sut.parse_checkers(lines))
         self.assertTrue('checker.one' in result)
         self.assertEqual('Checker One description', result.get('checker.one'))
         self.assertTrue('checker.two' in result)
         self.assertEqual('Checker Two description', result.get('checker.two'))
+
+
+class ClangIsCtuCapableTest(unittest.TestCase):
+    def test_ctu_not_found(self):
+        is_ctu = sut.is_ctu_capable('not-found-clang-func-mapping')
+        self.assertFalse(is_ctu)
+
+
+class ClangGetTripleArchTest(unittest.TestCase):
+    def test_arch_is_not_empty(self):
+        arch = sut.get_triple_arch(['clang', '-E', '-'], '.')
+        self.assertTrue(len(arch) > 0)