Driver: Enable address-significance tables by default when targeting COFF.

[rnk]

Remind me what the approximate size overhead of this is? I expect it is negligible, as most symbols are not address taken.

[pcc]

With ELF it was around 0.1% for a self-host of Clang. I also checked the overhead with COFF for Chromium's base_unittests and it was around 0.2% without debug info. I think that's small enough that we can turn this on by default.

[rnk]

Excellent!

[vitalybuka]

This breaks Windows bot
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/33846/steps/run%20check-asan/logs/stdio

742542.065 [0/1/37] Running the AddressSanitizer tests
-- Testing: 607 tests, 16 threads --
Testing: 0 .. 10.. 20.. 30.. 40.. 50
FAIL: AddressSanitizer-i386-windows :: TestCases/Windows/coverage-basic.cc (332 of 607)
******************** TEST 'AddressSanitizer-i386-windows :: TestCases/Windows/coverage-basic.cc' FAILED ********************
Script:
--
: 'RUN: at line 1';   rm -rf C:\b\slave\sanitizer-windows\build\projects\compiler-rt\test\asan\I386WindowsConfig\TestCases\Windows\Output\coverage-basic.cc.tmp-dir
: 'RUN: at line 2';   mkdir C:\b\slave\sanitizer-windows\build\projects\compiler-rt\test\asan\I386WindowsConfig\TestCases\Windows\Output\coverage-basic.cc.tmp-dir && cd C:\b\slave\sanitizer-windows\build\projects\compiler-rt\test\asan\I386WindowsConfig\TestCases\Windows\Output\coverage-basic.cc.tmp-dir
: 'RUN: at line 3';      C:/b/slave/sanitizer-windows/build/./bin/clang.exe  -fsanitize=address -mno-omit-leaf-frame-pointer -fno-omit-frame-pointer -fno-optimize-sibling-calls -gline-tables-only -gcodeview -gcolumn-info   -fms-compatibility-version=19.00.24215.1  -fsanitize-coverage=func C:\b\slave\sanitizer-windows\llvm\projects\compiler-rt\test\asan\TestCases\Windows\coverage-basic.cc -o test.exe
: 'RUN: at line 4';   env ASAN_OPTIONS=coverage=1  ./test.exe
: 'RUN: at line 6';   C:/Python27/python.exe C:/b/slave/sanitizer-windows/llvm/projects/compiler-rt\lib\sanitizer_common\scripts\sancov.py print *.sancov | FileCheck C:\b\slave\sanitizer-windows\llvm\projects\compiler-rt\test\asan\TestCases\Windows\coverage-basic.cc
--
Exit Code: 1120

Command Output (stdout):
--
$ ":" "RUN: at line 1"
$ "rm" "-rf" "C:\b\slave\sanitizer-windows\build\projects\compiler-rt\test\asan\I386WindowsConfig\TestCases\Windows\Output\coverage-basic.cc.tmp-dir"
$ ":" "RUN: at line 2"
$ "mkdir" "C:\b\slave\sanitizer-windows\build\projects\compiler-rt\test\asan\I386WindowsConfig\TestCases\Windows\Output\coverage-basic.cc.tmp-dir"
$ ":" "RUN: at line 3"
$ "C:/b/slave/sanitizer-windows/build/./bin/clang.exe" "-fsanitize=address" "-mno-omit-leaf-frame-pointer" "-fno-omit-frame-pointer" "-fno-optimize-sibling-calls" "-gline-tables-only" "-gcodeview" "-gcolumn-info" "-fms-compatibility-version=19.00.24215.1" "-fsanitize-coverage=func" "C:\b\slave\sanitizer-windows\llvm\projects\compiler-rt\test\asan\TestCases\Windows\coverage-basic.cc" "-o" "test.exe"
# command output:
   Creating library test.lib and object test.exp

coverage-basic-f4c01a.o : error LNK2001: unresolved external symbol ___sanitizer_cov_trace_pc

test.exe : fatal error LNK1120: 1 unresolved externals

[pcc]

Thanks, I'll take a look.

[pcc]

I received another report of breakage so I reverted in rC340579.

[pcc]

D51199 fixes the above breakage as well as crbug.com/877235. Once it lands, I'll reland this change.

lib/Driver/ToolChains/Clang.cpp

if (Arg *A = Args.getLastArg(options::OPT_moutline,
     } else {
       // Disable all outlining behaviour.
       CmdArgs.push_back("-mllvm");
       CmdArgs.push_back("-enable-machine-outliner=never");
     }
   }
 
   if (Args.hasFlag(options::OPT_faddrsig, options::OPT_fno_addrsig,
-                   getToolChain().getTriple().isOSBinFormatELF() &&
+                   (getToolChain().getTriple().isOSBinFormatELF() ||
+                    getToolChain().getTriple().isOSBinFormatCOFF()) &&
                        getToolChain().useIntegratedAs()))
     CmdArgs.push_back("-faddrsig");
 
   // Finally add the compile command to the compilation.
   if (Args.hasArg(options::OPT__SLASH_fallback) &&
       Output.getType() == types::TY_Object &&
       (InputType == types::TY_C || InputType == types::TY_CXX)) {
     auto CLCommand =

test/Driver/addrsig.c

 // RUN: %clang -### -target x86_64-unknown-linux -c %s 2>&1 | FileCheck -check-prefix=ADDRSIG %s
+// RUN: %clang -### -target x86_64-pc-win32 -c %s 2>&1 | FileCheck -check-prefix=ADDRSIG %s
 // RUN: %clang -### -target x86_64-unknown-linux -fno-integrated-as -c %s 2>&1 | FileCheck -check-prefix=NO-ADDRSIG %s
 // RUN: %clang -### -target x86_64-unknown-linux -fno-integrated-as -faddrsig -c %s 2>&1 | FileCheck -check-prefix=ADDRSIG %s
 // RUN: %clang -### -target x86_64-unknown-linux -fno-addrsig -c %s 2>&1 | FileCheck -check-prefix=NO-ADDRSIG %s
 // RUN: %clang -### -target x86_64-apple-darwin -c %s 2>&1 | FileCheck -check-prefix=NO-ADDRSIG %s
 
 // ADDRSIG: -faddrsig
 // NO-ADDRSIG-NOT: -faddrsig