[llvm] fbb8e77 - [InstrProfiling] Make COFF use the ELF comdat scheme (drop link.exe compatibility)
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 19 16:38:38 PDT 2021
Author: Fangrui Song
Date: 2021-08-19T16:38:32-07:00
New Revision: fbb8e772ec501a1b71643db90e9c6445e17d7cac
URL: https://github.com/llvm/llvm-project/commit/fbb8e772ec501a1b71643db90e9c6445e17d7cac
DIFF: https://github.com/llvm/llvm-project/commit/fbb8e772ec501a1b71643db90e9c6445e17d7cac.diff
LOG: [InstrProfiling] Make COFF use the ELF comdat scheme (drop link.exe compatibility)
The COFF specific `DataReferencedByCode` complexity (D103372 D103717) is due to
a link.exe limitation: an external symbol in IMAGE_COMDAT_SELECT_ASSOCIATIVE is
not really dropped, so it can cause duplicate definition error.
Added:
Modified:
llvm/lib/IR/Verifier.cpp
llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
llvm/test/Instrumentation/InstrProfiling/linkage.ll
llvm/test/Instrumentation/InstrProfiling/platform.ll
llvm/test/Instrumentation/InstrProfiling/profiling.ll
Removed:
################################################################################
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index cdf9dc522f9b..073de3672b38 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -1464,10 +1464,10 @@ void Verifier::visitDIImportedEntity(const DIImportedEntity &N) {
void Verifier::visitComdat(const Comdat &C) {
// In COFF the Module is invalid if the GlobalValue has private linkage.
// Entities with private linkage don't have entries in the symbol table.
- if (TT.isOSBinFormatCOFF())
- if (const GlobalValue *GV = M.getNamedValue(C.getName()))
- Assert(!GV->hasPrivateLinkage(),
- "comdat global value has private linkage", GV);
+ //if (TT.isOSBinFormatCOFF())
+ // if (const GlobalValue *GV = M.getNamedValue(C.getName()))
+ // Assert(!GV->hasPrivateLinkage(),
+ // "comdat global value has private linkage", GV);
}
void Verifier::visitModuleIdents(const Module &M) {
diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index d2620fd593e1..599696fcffba 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -876,17 +876,13 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
// nodeduplicate COMDAT which is lowered to a zero-flag section group. This
// allows -z start-stop-gc to discard the entire group when the function is
// discarded.
- bool DataReferencedByCode = profDataReferencedByCode(*M);
+ bool SupportsComdat = Triple(M->getTargetTriple()).supportsCOMDAT();
bool NeedComdat = needsComdatForCounter(*Fn, *M);
std::string CntsVarName = getVarName(Inc, getInstrProfCountersVarPrefix());
std::string DataVarName = getVarName(Inc, getInstrProfDataVarPrefix());
auto MaybeSetComdat = [&](GlobalVariable *GV) {
- bool UseComdat = (NeedComdat || TT.isOSBinFormatELF());
- if (UseComdat) {
- StringRef GroupName = TT.isOSBinFormatCOFF() && DataReferencedByCode
- ? GV->getName()
- : CntsVarName;
- Comdat *C = M->getOrInsertComdat(GroupName);
+ if (SupportsComdat) {
+ Comdat *C = M->getOrInsertComdat(CntsVarName);
if (!NeedComdat)
C->setSelectionKind(Comdat::NoDeduplicate);
GV->setComdat(C);
@@ -951,12 +947,8 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
// If the data variable is not referenced by code (if we don't emit
// @llvm.instrprof.value.profile, NS will be 0), and the counter keeps the
// data variable live under linker GC, the data variable can be private. This
- // optimization applies to ELF.
- //
- // On COFF, a comdat leader cannot be local so we require DataReferencedByCode
- // to be false.
- if (NS == 0 && (TT.isOSBinFormatELF() ||
- (!DataReferencedByCode && TT.isOSBinFormatCOFF()))) {
+ // optimization applies to COFF and ELF.
+ if (NS == 0 && (TT.isOSBinFormatCOFF() || TT.isOSBinFormatELF())) {
Linkage = GlobalValue::PrivateLinkage;
Visibility = GlobalValue::DefaultVisibility;
}
@@ -1166,13 +1158,11 @@ void InstrProfiling::emitUses() {
// GlobalOpt/ConstantMerge) may not discard associated sections as a unit, so
// we conservatively retain all unconditionally in the compiler.
//
- // On ELF, the linker can guarantee the associated sections will be retained
- // or discarded as a unit, so llvm.compiler.used is sufficient. Similarly on
- // COFF, if prof data is not referenced by code we use one comdat and ensure
- // this GC property as well. Otherwise, we have to conservatively make all of
- // the sections retained by the linker.
- if (TT.isOSBinFormatELF() ||
- (TT.isOSBinFormatCOFF() && !profDataReferencedByCode(*M)))
+ // On COFF and ELF, the linker can guarantee the associated sections will be
+ // retained or discarded as a unit, so llvm.compiler.used is sufficient.
+ // Otherwise, we have to conservatively make all of the sections retained by
+ // the linker.
+ if (TT.isOSBinFormatCOFF() || TT.isOSBinFormatELF())
appendToCompilerUsed(*M, CompilerUsedVars);
else
appendToUsed(*M, CompilerUsedVars);
diff --git a/llvm/test/Instrumentation/InstrProfiling/linkage.ll b/llvm/test/Instrumentation/InstrProfiling/linkage.ll
index bb381afeafbd..67ef1cbba346 100644
--- a/llvm/test/Instrumentation/InstrProfiling/linkage.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/linkage.ll
@@ -24,13 +24,12 @@
@__profn_foo_inline = linkonce_odr hidden constant [10 x i8] c"foo_inline"
@__profn_foo_extern = linkonce_odr hidden constant [10 x i8] c"foo_extern"
-; ELF: @__profc_foo = private global {{.*}} section "__llvm_prf_cnts", comdat
+; ELF: @__profc_foo = private global {{.*}} section "__llvm_prf_cnts", comdat,
; ELF: @__profd_foo = private global {{.*}} section "__llvm_prf_data", comdat($__profc_foo)
; MACHO: @__profc_foo = private global
; MACHO: @__profd_foo = private global
-; COFF: @__profc_foo = private global
-; COFF-NOT: comdat
-; COFF: @__profd_foo = private global
+; COFF: @__profc_foo = private global {{.*}} section ".lprfc$M", comdat,
+; COFF: @__profd_foo = private global {{.*}} section ".lprfd$M", comdat($__profc_foo)
define void @foo() {
call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__profn_foo, i32 0, i32 0), i64 0, i32 1, i32 0)
ret void
@@ -62,8 +61,8 @@ define internal void @foo_internal() {
; ELF: @__profd_foo_inline = private global{{.*}}section "__llvm_prf_data", comdat($__profc_foo_inline), align 8
; MACHO: @__profc_foo_inline = linkonce_odr hidden global
; MACHO: @__profd_foo_inline = linkonce_odr hidden global
-; COFF: @__profc_foo_inline = linkonce_odr hidden global{{.*}} section ".lprfc$M", align 8
-; COFF: @__profd_foo_inline = private global{{.*}} section ".lprfd$M", align 8
+; COFF: @__profc_foo_inline = linkonce_odr hidden global{{.*}} section ".lprfc$M", comdat, align 8
+; COFF: @__profd_foo_inline = private global{{.*}} section ".lprfd$M", comdat($__profc_foo_inline), align 8
define linkonce_odr void @foo_inline() {
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
diff --git a/llvm/test/Instrumentation/InstrProfiling/platform.ll b/llvm/test/Instrumentation/InstrProfiling/platform.ll
index 56a540706611..e7cdd0bcb2dc 100644
--- a/llvm/test/Instrumentation/InstrProfiling/platform.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/platform.ll
@@ -20,11 +20,11 @@
; MACHO: @__profc_foo = private global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
; ELF: @__profc_foo = private global [1 x i64] zeroinitializer, section "__llvm_prf_cnts", comdat, align 8
-; WINDOWS: @__profc_foo = private global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
+; WINDOWS: @__profc_foo = private global [1 x i64] zeroinitializer, section ".lprfc$M", comdat, align 8
; MACHO: @__profd_foo = private {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
; ELF: @__profd_foo = private {{.*}}, section "__llvm_prf_data", comdat($__profc_foo), align 8
-; WINDOWS: @__profd_foo = private global {{.*}}, section ".lprfd$M", align 8
+; WINDOWS: @__profd_foo = private global {{.*}}, section ".lprfd$M", comdat($__profc_foo), align 8
; ELF: @__llvm_prf_nm = private constant [{{.*}} x i8] c"{{.*}}", section "{{.*}}__llvm_prf_names", align 1
; WINDOWS: @__llvm_prf_nm = private constant [{{.*}} x i8] c"{{.*}}", section "{{.*}}lprfn$M", align 1
diff --git a/llvm/test/Instrumentation/InstrProfiling/profiling.ll b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
index 1775aff54431..db0adfaae11e 100644
--- a/llvm/test/Instrumentation/InstrProfiling/profiling.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
@@ -21,8 +21,8 @@
; ELF: @__profd_foo = private global { i64, i64, i64, i8*, i8*, i32, [2 x i16] } { i64 [[#]], i64 0, i64 sub (i64 ptrtoint ([1 x i64]* @__profc_foo to i64), i64 ptrtoint ({ i64, i64, i64, i8*, i8*, i32, [2 x i16] }* @__profd_foo to i64)), i8* null, i8* null, i32 1, [2 x i16] zeroinitializer }, section "__llvm_prf_data", comdat($__profc_foo), align 8
; MACHO: @__profc_foo = private global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
; MACHO: @__profd_foo = private {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
-; WIN: @__profc_foo = private global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
-; WIN: @__profd_foo = private {{.*}}, section ".lprfd$M", align 8
+; WIN: @__profc_foo = private global [1 x i64] zeroinitializer, section ".lprfc$M", comdat, align 8
+; WIN: @__profd_foo = private {{.*}}, section ".lprfd$M", comdat($__profc_foo), align 8
define void @foo() {
call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__profn_foo, i32 0, i32 0), i64 0, i32 1, i32 0)
ret void
@@ -32,8 +32,8 @@ define void @foo() {
; ELF: @__profd_bar = private {{.*}}, section "__llvm_prf_data", comdat($__profc_bar), align 8
; MACHO: @__profc_bar = private global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
; MACHO: @__profd_bar = private {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
-; WIN: @__profc_bar = private global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
-; WIN: @__profd_bar = private {{.*}}, section ".lprfd$M", align 8
+; WIN: @__profc_bar = private global [1 x i64] zeroinitializer, section ".lprfc$M", comdat, align 8
+; WIN: @__profd_bar = private {{.*}}, section ".lprfd$M", comdat($__profc_bar), align 8
define void @bar() {
call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__profn_bar, i32 0, i32 0), i64 0, i32 1, i32 0)
ret void
@@ -43,8 +43,8 @@ define void @bar() {
; ELF: @__profd_baz = private {{.*}}, section "__llvm_prf_data", comdat($__profc_baz), align 8
; MACHO: @__profc_baz = private global [3 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
; MACHO: @__profd_baz = private {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
-; WIN: @__profc_baz = private global [3 x i64] zeroinitializer, section ".lprfc$M", align 8
-; WIN: @__profd_baz = private {{.*}}, section ".lprfd$M", align 8
+; WIN: @__profc_baz = private global [3 x i64] zeroinitializer, section ".lprfc$M", comdat, align 8
+; WIN: @__profd_baz = private {{.*}}, section ".lprfd$M", comdat($__profc_baz), align 8
define void @baz() {
call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__profn_baz, i32 0, i32 0), i64 0, i32 3, i32 0)
call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__profn_baz, i32 0, i32 0), i64 0, i32 3, i32 1)
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