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[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
This commit is contained in:
Reid Kleckner 2019-09-17 21:10:49 +00:00
parent 0c8e4a2e0d
commit 23e872a3d0
4 changed files with 21 additions and 16 deletions
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29
llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
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@ -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;

2
llvm/test/Instrumentation/InstrProfiling/PR23499.ll
View File

@ -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

4
llvm/test/Instrumentation/InstrProfiling/comdat.ll
View File

@ -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

2
llvm/test/Instrumentation/InstrProfiling/linkage.ll
View File

@ -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