[PGO] Don't use comdat groups for counters & data on COFF

For COFF, a comdat group is really a symbol marked
IMAGE_COMDAT_SELECT_ANY and zero or more other symbols marked
IMAGE_COMDAT_SELECT_ASSOCIATIVE. Typically the associative symbols in
the group are not external and are not referenced by other TUs, they are
things like debug info, C++ dynamic initializers, or other section
registration schemes. The Visual C++ linker reports a duplicate symbol
error for symbols marked IMAGE_COMDAT_SELECT_ASSOCIATIVE even if they
would be discarded after handling the leader symbol.

Fixes coverage-inline.cpp in check-profile after r372020.

llvm-svn: 372182

diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 65773bb..5c1df16 100644 (file)
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -757,20 +757,25 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
   // new comdat group for the counters and profiling data. If we use the comdat
   // of the parent function, that will result in relocations against discarded
   // sections.
-  Comdat *Cmdt = nullptr;
-  if (needsComdatForCounter(*Fn, *M)) {
-    StringRef CmdtPrefix = getInstrProfComdatPrefix();
+  bool NeedComdat = needsComdatForCounter(*Fn, *M);
+  Comdat *Cmdt = nullptr; // Comdat group.
+  if (NeedComdat) {
     if (TT.isOSBinFormatCOFF()) {
-      // For COFF, the comdat group name must be the name of a symbol in the
-      // group. Use the counter variable name, and upgrade its linkage to
-      // something externally visible, like linkonce_odr. Use hidden visibility
-      // to imply that this is dso local.
-      CmdtPrefix = getInstrProfCountersVarPrefix();
+      // For COFF, put the counters, data, and values each into their own
+      // comdats. We can't use a group because the Visual C++ linker will
+      // report duplicate symbol errors if there are multiple external symbols
+      // with the same name marked IMAGE_COMDAT_SELECT_ASSOCIATIVE.
       Linkage = GlobalValue::LinkOnceODRLinkage;
       Visibility = GlobalValue::HiddenVisibility;
+    } else {
+      // Otherwise, create one comdat group for everything.
+      Cmdt = M->getOrInsertComdat(getVarName(Inc, getInstrProfComdatPrefix()));
     }
-    Cmdt = M->getOrInsertComdat(getVarName(Inc, CmdtPrefix));
   }
+  auto MaybeSetComdat = [=](GlobalVariable *GV) {
+    if (NeedComdat)
+      GV->setComdat(Cmdt ? Cmdt : M->getOrInsertComdat(GV->getName()));
+  };
 
   uint64_t NumCounters = Inc->getNumCounters()->getZExtValue();
   LLVMContext &Ctx = M->getContext();
@@ -785,7 +790,7 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
   CounterPtr->setSection(
       getInstrProfSectionName(IPSK_cnts, TT.getObjectFormat()));
   CounterPtr->setAlignment(8);
-  CounterPtr->setComdat(Cmdt);
+  MaybeSetComdat(CounterPtr);
   CounterPtr->setLinkage(Linkage);
 
   auto *Int8PtrTy = Type::getInt8PtrTy(Ctx);
@@ -807,7 +812,7 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
       ValuesVar->setSection(
           getInstrProfSectionName(IPSK_vals, TT.getObjectFormat()));
       ValuesVar->setAlignment(8);
-      ValuesVar->setComdat(Cmdt);
+      MaybeSetComdat(ValuesVar);
       ValuesPtrExpr =
           ConstantExpr::getBitCast(ValuesVar, Type::getInt8PtrTy(Ctx));
     }
@@ -840,7 +845,7 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
   Data->setVisibility(Visibility);
   Data->setSection(getInstrProfSectionName(IPSK_data, TT.getObjectFormat()));
   Data->setAlignment(INSTR_PROF_DATA_ALIGNMENT);
-  Data->setComdat(Cmdt);
+  MaybeSetComdat(Data);
   Data->setLinkage(Linkage);
 
   PD.RegionCounters = CounterPtr;

diff --git a/llvm/test/Instrumentation/InstrProfiling/PR23499.ll b/llvm/test/Instrumentation/InstrProfiling/PR23499.ll
index 81be1dc..a5e20b1 100644 (file)
--- a/llvm/test/Instrumentation/InstrProfiling/PR23499.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/PR23499.ll
@@ -21,7 +21,7 @@ $_Z3barIvEvv = comdat any
 
 ; COFF-NOT: __profn__Z3barIvEvv
 ; COFF: @__profc__Z3barIvEvv = linkonce_odr hidden global [1 x i64] zeroinitializer, section "{{.*}}prfc$M", comdat, align 8
-; COFF: @__profd__Z3barIvEvv = linkonce_odr hidden global { i64, i64, i64*, i8*, i8*, i32, [2 x i16] } { i64 4947693190065689389, i64 0, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3barIvEvv, i32 0, i32 0), i8*{{.*}}, i8* null, i32 1, [2 x i16] zeroinitializer }, section "{{.*}}prfd{{.*}}", comdat($__profc__Z3barIvEvv), align 8
+; COFF: @__profd__Z3barIvEvv = linkonce_odr hidden global { i64, i64, i64*, i8*, i8*, i32, [2 x i16] } { i64 4947693190065689389, i64 0, i64* getelementptr inbounds ([1 x i64], [1 x i64]* @__profc__Z3barIvEvv, i32 0, i32 0), i8*{{.*}}, i8* null, i32 1, [2 x i16] zeroinitializer }, section "{{.*}}prfd{{.*}}", comdat, align 8
 
 
 declare void @llvm.instrprof.increment(i8*, i64, i32, i32) #1

diff --git a/llvm/test/Instrumentation/InstrProfiling/comdat.ll b/llvm/test/Instrumentation/InstrProfiling/comdat.ll
index bea8e1d..5ff820c 100644 (file)
--- a/llvm/test/Instrumentation/InstrProfiling/comdat.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/comdat.ll
@@ -18,7 +18,7 @@ $foo_inline = comdat any
 ; ELF: @__profc_foo_inline = linkonce_odr hidden global{{.*}}, section "__llvm_prf_cnts", comdat($__profv_foo_inline), align 8
 ; ELF: @__profd_foo_inline = linkonce_odr hidden global{{.*}}, section "__llvm_prf_data", comdat($__profv_foo_inline), align 8
 ; COFF: @__profc_foo_inline = linkonce_odr hidden global{{.*}}, section ".lprfc$M", comdat, align 8
-; COFF: @__profd_foo_inline = linkonce_odr hidden global{{.*}}, section ".lprfd$M", comdat($__profc_foo_inline), align 8
+; COFF: @__profd_foo_inline = linkonce_odr hidden global{{.*}}, section ".lprfd$M", comdat, align 8
 define weak_odr void @foo_inline() comdat {
   call void @llvm.instrprof.increment(i8* getelementptr inbounds ([10 x i8], [10 x i8]* @__profn_foo_inline, i32 0, i32 0), i64 0, i32 1, i32 0)
   ret void
@@ -31,7 +31,7 @@ $foo_extern = comdat any
 ; ELF: @__profc_foo_extern = linkonce_odr hidden global{{.*}}, section "__llvm_prf_cnts", comdat($__profv_foo_extern)
 ; ELF: @__profd_foo_extern = linkonce_odr hidden global{{.*}}, section "__llvm_prf_data", comdat($__profv_foo_extern)
 ; COFF: @__profc_foo_extern = linkonce_odr hidden global{{.*}}, section ".lprfc$M", comdat, align 8
-; COFF: @__profd_foo_extern = linkonce_odr hidden global{{.*}}, section ".lprfd$M", comdat($__profc_foo_extern), align 8
+; COFF: @__profd_foo_extern = linkonce_odr hidden global{{.*}}, section ".lprfd$M", comdat, align 8
 define available_externally void @foo_extern() {
   call void @llvm.instrprof.increment(i8* getelementptr inbounds ([10 x i8], [10 x i8]* @__profn_foo_extern, i32 0, i32 0), i64 0, i32 1, i32 0)
   ret void

diff --git a/llvm/test/Instrumentation/InstrProfiling/linkage.ll b/llvm/test/Instrumentation/InstrProfiling/linkage.ll
index e086add..13e389b 100644 (file)
--- a/llvm/test/Instrumentation/InstrProfiling/linkage.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/linkage.ll
@@ -58,7 +58,7 @@ define linkonce_odr void @foo_inline() {
 ; MACHO: @__profc_foo_extern = linkonce_odr hidden global
 ; MACHO: @__profd_foo_extern = linkonce_odr hidden global
 ; COFF: @__profc_foo_extern = linkonce_odr hidden global {{.*}}section ".lprfc$M", comdat, align 8
-; COFF: @__profd_foo_extern = linkonce_odr hidden global {{.*}}section ".lprfd$M", comdat($__profc_foo_extern), align 8
+; COFF: @__profd_foo_extern = linkonce_odr hidden global {{.*}}section ".lprfd$M", comdat, align 8
 define available_externally void @foo_extern() {
   call void @llvm.instrprof.increment(i8* getelementptr inbounds ([10 x i8], [10 x i8]* @__profn_foo_extern, i32 0, i32 0), i64 0, i32 1, i32 0)
   ret void