[llvm] r256220 - [PGO] Fix another comdat related issue for COFF

[Xinliang David Li via llvm-commits]

Author: davidxl
Date: Mon Dec 21 18:11:15 2015
New Revision: 256220

URL: http://llvm.org/viewvc/llvm-project?rev=256220&view=rev
Log:
[PGO] Fix another comdat related issue for COFF

The linker requires that a comdat section must be associated
with a another comdat section that precedes it. This
means the comdat section's name needs to use the  profile name
var's name.

Patch tested by Johan Engelen.


Modified:
    llvm/trunk/lib/Transforms/Instrumentation/InstrProfiling.cpp
    llvm/trunk/test/Instrumentation/InstrProfiling/PR23499.ll

Modified: llvm/trunk/lib/Transforms/Instrumentation/InstrProfiling.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/InstrProfiling.cpp?rev=256220&r1=256219&r2=256220&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/InstrProfiling.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/InstrProfiling.cpp Mon Dec 21 18:11:15 2015
@@ -282,9 +282,11 @@ static inline bool shouldRecordFunctionA
 static inline Comdat *getOrCreateProfileComdat(Module &M,
                                                InstrProfIncrementInst *Inc) {
   // COFF format requires a COMDAT section to have a key symbol with the same
-  // name.
+  // name. The linker targeting COFF also requires that the COMDAT section
+  // a section is associated to must precede the associating section. For this
+  // reason, we must choose the name var's name as the name of the comdat.
   StringRef ComdatPrefix = (Triple(M.getTargetTriple()).isOSBinFormatCOFF()
-                                ? getInstrProfDataVarPrefix()
+                                ? getInstrProfNameVarPrefix()
                                 : getInstrProfComdatPrefix());
   return M.getOrInsertComdat(StringRef(getVarName(Inc, ComdatPrefix)));
 }

Modified: llvm/trunk/test/Instrumentation/InstrProfiling/PR23499.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/InstrProfiling/PR23499.ll?rev=256220&r1=256219&r2=256220&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/InstrProfiling/PR23499.ll (original)
+++ llvm/trunk/test/Instrumentation/InstrProfiling/PR23499.ll Mon Dec 21 18:11:15 2015
@@ -14,9 +14,9 @@ $_Z3barIvEvv = comdat any
 ; CHECK: @__profc__Z3barIvEvv = linkonce_odr hidden global [1 x i64] zeroinitializer, section "{{.*}}__llvm_prf_cnts", comdat($__profv__Z3barIvEvv), align 8
 ; CHECK: @__profd__Z3barIvEvv = linkonce_odr hidden global { i32, i32, i64, i8*, i64*, i8*, i8*, [1 x i16] } { i32 11, i32 1, i64 0, i8* getelementptr inbounds ([11 x i8], [11 x i8]* @__profn__Z3barIvEvv, i32 0, i32 0), i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3barIvEvv, i32 0, i32 0), i8* null, i8* null, [1 x i16] zeroinitializer }, section "{{.*}}__llvm_prf_data", comdat($__profv__Z3barIvEvv), align 8
 
-; COFF: @__profn__Z3barIvEvv = linkonce_odr hidden constant [11 x i8] c"_Z3barIvEvv", section "{{.*}}__llvm_prf_names", comdat($__profd__Z3barIvEvv), align 1
-; COFF: @__profc__Z3barIvEvv = linkonce_odr hidden global [1 x i64] zeroinitializer, section "{{.*}}__llvm_prf_cnts", comdat($__profd__Z3barIvEvv), align 8
-; COFF: @__profd__Z3barIvEvv = linkonce_odr hidden global { i32, i32, i64, i8*, i64*, i8*, i8*, [1 x i16] } { i32 11, i32 1, i64 0, i8* getelementptr inbounds ([11 x i8], [11 x i8]* @__profn__Z3barIvEvv, i32 0, i32 0), i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3barIvEvv, i32 0, i32 0), i8* null, i8* null, [1 x i16] zeroinitializer }, section "{{.*}}__llvm_prf_data", comdat, align 8
+; COFF: @__profn__Z3barIvEvv = linkonce_odr hidden constant [11 x i8] c"_Z3barIvEvv", section "{{.*}}__llvm_prf_names", comdat, align 1
+; COFF: @__profc__Z3barIvEvv = linkonce_odr hidden global [1 x i64] zeroinitializer, section "{{.*}}__llvm_prf_cnts", comdat($__profn__Z3barIvEvv), align 8
+; COFF: @__profd__Z3barIvEvv = linkonce_odr hidden global { i32, i32, i64, i8*, i64*, i8*, i8*, [1 x i16] } { i32 11, i32 1, i64 0, i8* getelementptr inbounds ([11 x i8], [11 x i8]* @__profn__Z3barIvEvv, i32 0, i32 0), i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3barIvEvv, i32 0, i32 0), i8* null, i8* null, [1 x i16] zeroinitializer }, section "{{.*}}__llvm_prf_data", comdat($__profn__Z3barIvEvv), align 8
 
 
 declare void @llvm.instrprof.increment(i8*, i64, i32, i32) #1