[clang] use getCommonSugar in an assortment of places

[mizvekov]

Summary

For this patch, a simple search was performed for patterns where there are
two types (usually an LHS and an RHS) which are structurally the same, and there
is some result type which is resolved as either one of them (typically LHS for
consistency).

We change those cases to resolve as the common sugared type between those two,
utilizing the new infrastructure created for this purpose.

Signed-off-by: Matheus Izvekov <[e-mail]>

[mizvekov]

In D111509#3168178, @shafik wrote:

Changing how types are printed can effect LLDB expression parsing tests. I ran the LLDB test suite with this change:

ninja check-lldb

and it changes to the results for TestScalarURem.py which can be run using:

llvm-lit -sv lldb/test --filter TestScalarURem.py

The change looks expected.

Fixed now, thanks. (And also API/commands/expression/rdar44436068/Test128BitsInteger.py).

[tra]

It appears that this change may result in clang crashing (e.g. it broke CUDA compilation: https://lab.llvm.org/buildbot/#/builders/55/builds/35047/steps/3/logs/stdio).

Reproducer:

class {
  typedef __complex__ a;
  operator=(double b){c *= b} a c

$bin/clang++ -cc1 -triple x86_64-unknown-linux-gnu -fsyntax-only -std=c++14 -disable-llvm-passes -x c++ reproducer.cc
reproducer.cc:2:11: warning: plain '_Complex' requires a type specifier; assuming '_Complex double'
  typedef __complex__ a;
          ^
                      double
reproducer.cc:3:3: error: a type specifier is required for all declarations
  operator=(double b){c *= b} a c
  ^
reproducer.cc:3:34: error: expected ';' at end of declaration list
  operator=(double b){c *= b} a c
                                 ^
                                 ;
reproducer.cc:4:1: error: expected '}'
^
reproducer.cc:1:7: note: to match this '{'
class {
      ^
clang++: work/llvm/repo/llvm/include/llvm/Support/Casting.h:566: decltype(auto) llvm::cast(const From &) [To = clang::BuiltinType, From = clang::QualType]: Assertion `isa<To>(Val) && "cast<Ty>() argument of incompatible type!"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: bin/clang++ -cc1 -triple x86_64-unknown-linux-gnu -fsyntax-only -std=c++14 -disable-llvm-passes -x c++ reproducer.cc
1.      reproducer.cc:3:29: current parser token '}'
2.      reproducer.cc:1:1: parsing struct/union/class body '(anonymous)'
3.      reproducer.cc:3:22: parsing function body '(anonymous class)::operator='
4.      reproducer.cc:3:22: in compound statement ('{}')
 #0 0x000055ad5d7fe49a llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) work/llvm/repo/llvm/lib/Support/Unix/Signals.inc:569:11
 #1 0x000055ad5d7fe64b PrintStackTraceSignalHandler(void*) work/llvm/repo/llvm/lib/Support/Unix/Signals.inc:636:1
 #2 0x000055ad5d7fcc96 llvm::sys::RunSignalHandlers() work/llvm/repo/llvm/lib/Support/Signals.cpp:103:5
 #3 0x000055ad5d7fed75 SignalHandler(int) work/llvm/repo/llvm/lib/Support/Unix/Signals.inc:407:1
 #4 0x00007f4b4e083200 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x12200)
 #5 0x00007f4b4daf28c1 raise ./signal/../sysdeps/unix/sysv/linux/raise.c:50:1
 #6 0x00007f4b4dadc546 abort ./stdlib/abort.c:81:7
 #7 0x00007f4b4dadc42f get_sysdep_segment_value ./intl/loadmsgcat.c:509:8
 #8 0x00007f4b4dadc42f _nl_load_domain ./intl/loadmsgcat.c:970:34
 #9 0x00007f4b4daeb242 (/lib/x86_64-linux-gnu/libc.so.6+0x31242)
#10 0x000055ad5e2f39e8 decltype(auto) llvm::cast<clang::BuiltinType, clang::QualType>(clang::QualType const&) work/llvm/repo/llvm/include/llvm/Support/Casting.h:567:43
#11 0x000055ad5e2f3929 clang::BuiltinType const* clang::Type::castAs<clang::BuiltinType>() const work/llvm/build/debug/tools/clang/include/clang/AST/TypeNodes.inc:86:1
#12 0x000055ad62cfe279 clang::ASTContext::getFloatTypeSemantics(clang::QualType) const work/llvm/repo/clang/lib/AST/ASTContext.cpp:1707:14
#13 0x000055ad61e8ad61 unsupportedTypeConversion(clang::Sema const&, clang::QualType, clang::QualType) work/llvm/repo/clang/lib/Sema/SemaExpr.cpp:1256:29
#14 0x000055ad61eb3961 clang::Sema::CheckAssignmentConstraints(clang::QualType, clang::ActionResult<clang::Expr*, true>&, clang::CastKind&, bool) work/llvm/repo/clang/lib/Sema/SemaExpr.cpp:9619:7
#15 0x000055ad61eb30c5 clang::Sema::CheckAssignmentConstraints(clang::SourceLocation, clang::QualType, clang::QualType) work/llvm/repo/clang/lib/Sema/SemaExpr.cpp:9465:3
#16 0x000055ad61ec565f clang::Sema::CheckAssignmentOperands(clang::Expr*, clang::ActionResult<clang::Expr*, true>&, clang::SourceLocation, clang::QualType, clang::BinaryOperatorKind) work/llvm/repo/clang/lib/Sema/SemaExpr.cpp:13919:12
#17 0x000055ad61ea1903 clang::Sema::CreateBuiltinBinOp(clang::SourceLocation, clang::BinaryOperatorKind, clang::Expr*, clang::Expr*) work/llvm/repo/clang/lib/Sema/SemaExpr.cpp:14988:11
#18 0x000055ad61ecaf02 clang::Sema::BuildBinOp(clang::Scope*, clang::SourceLocation, clang::BinaryOperatorKind, clang::Expr*, clang::Expr*) work/llvm/repo/clang/lib/Sema/SemaExpr.cpp:15511:10
#19 0x000055ad61e8a180 clang::Sema::ActOnBinOp(clang::Scope*, clang::SourceLocation, clang::tok::TokenKind, clang::Expr*, clang::Expr*) work/llvm/repo/clang/lib/Sema/SemaExpr.cpp:15323:10

[mizvekov]

Thanks for the repro!

[ronlieb]

i am seeing similar issues in openmp buildbot failing with this patch

[mizvekov]

In D111509#3778277, @ronlieb wrote:

i am seeing similar issues in openmp buildbot failing with this patch

I got a small patch coming up soon.

[mizvekov]

Fix at https://reviews.llvm.org/D133522

[MaskRay]

Since the fix was not merged, I will revert this soon.

I saw a clang segfault with clang++ libstdc++-v3/src/c++98/complex_io.cc

[mizvekov]

In D111509#3778879, @MaskRay wrote:

Since the fix was not merged, I will revert this soon.

I saw a clang segfault with clang++ libstdc++-v3/src/c++98/complex_io.cc

Would you mind if I just merge it? I was hoping there would be someone around to have a quick look, but apparently not.

[MaskRay]

In D111509#3778882, @mizvekov wrote:

In D111509#3778879, @MaskRay wrote:

Since the fix was not merged, I will revert this soon.

I saw a clang segfault with clang++ libstdc++-v3/src/c++98/complex_io.cc

Would you mind if I just merge it? I was hoping there would be someone around to have a quick look, but apparently not.

Sorry, I just reverted it:) You may check whether the fix fixes GCC libstdc++-v3/src/c++98/complex_io.cc

[mizvekov]

clang/lib/Sema/SemaExpr.cpp

1091–1156

@shafik let's continue revision of D133522 in this patch, since that one was a quick fix that I attempted in order to avoid reverting it. But now that it was reverted, I will abandon the other one.

I have highlighted with this comment the areas affected by D133522 so we can continue here.

But now I have refactored the whole thing to be simpler / more readable.

[mizvekov]

In D111509#3778883, @MaskRay wrote:

Sorry, I just reverted it:) You may check whether the fix fixes GCC libstdc++-v3/src/c++98/complex_io.cc

I confirm it does not crash on my system with this patch.

[mizvekov]

clang/lib/Sema/SemaExpr.cpp

1091–1156

Also @davrec if you can please take a look at this, this is the only part of the patch that changed, in order to fix the reason why it was reverted.

[davrec]

The lines you changed (clang/lib/Sema/SemaExpr.cpp:1091-1150) look good (IIUC you just change cast to cast_as and dyn_cast to getAs, and reorganize for clarity). I suggested some renaming and a few more comments to further clarify.

clang/lib/Sema/SemaExpr.cpp

1113–1114

Rename params for clarity, e.g.
LHS->Longer
LHSType->LongerType
RHSType->ShorterType

1146–1147

// Compute the rank of the two types, regardless of whether they are complex.

1151–1155

// Promote the precision of the LHS if not an assignment.

1153

// Promote the precision of the RHS unless it is already the same as the LHS.

[davrec]

clang/lib/Sema/SemaExpr.cpp

1113–1114

Actually I probably have that backwards, I think LHS is the Shorter expression...in any case you see why renaming would be helpful