[compiler-rt] 87c43f3 - [InstrProfiling] Delete linkage/visibility toggling for Windows
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Wed Jun 2 16:50:00 PDT 2021
Author: Fangrui Song
Date: 2021-06-02T16:49:54-07:00
New Revision: 87c43f3aa99d778755c7f5420e955885f855ecad
URL: https://github.com/llvm/llvm-project/commit/87c43f3aa99d778755c7f5420e955885f855ecad
DIFF: https://github.com/llvm/llvm-project/commit/87c43f3aa99d778755c7f5420e955885f855ecad.diff
LOG: [InstrProfiling] Delete linkage/visibility toggling for Windows
The linkage/visibility of `__profn_*` variables are derived
from the profiled functions.
extern_weak => linkonce
available_externally => linkonce_odr
internal => private
extern => private
_ => unchanged
The linkage/visibility of `__profc_*`/`__profd_*` variables are derived from
`__profn_*` with linkage/visibility wrestling for Windows.
The changes can be folded to the following without changing semantics.
```
if (TT.isOSBinFormatCOFF() && !NeedComdat) {
Linkage = GlobalValue::InternalLinkage;
Visibility = GlobalValue::DefaultVisibility;
}
```
That said, I think we can just delete the code block.
An extern/internal function will now use private `__profc_*`/`__profd_*`
variables, instead of internal ones. This saves some symbol table entries.
A non-comdat {linkonce,weak}_odr function will now use hidden external
`__profc_*`/`__profd_*` variables instead of internal ones. There is potential
object file size increase because such symbols need `/INCLUDE:` directives.
However such non-comdat functions are rare (note that non-comdat weak
definitions don't prevent duplicate definition error).
The behavior changes match ELF.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D103355
Added:
Modified:
compiler-rt/test/profile/Windows/coverage-weak-lld.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/compiler-rt/test/profile/Windows/coverage-weak-lld.cpp b/compiler-rt/test/profile/Windows/coverage-weak-lld.cpp
index b1708433cec22..1dc74cb22fa3f 100644
--- a/compiler-rt/test/profile/Windows/coverage-weak-lld.cpp
+++ b/compiler-rt/test/profile/Windows/coverage-weak-lld.cpp
@@ -51,6 +51,8 @@
// CHECK2: weak
// CHECK2: weak
+/// __profc__Z4weakv in %t2.o is weak and resolves to the value of %t0.o's copy.
+/// Without GC it takes a duplicate entry.
// PROFILE2: ?weak@@YAXXZ:
// PROFILE2-NEXT: Hash:
// PROFILE2-NEXT: Counters: 1
@@ -58,7 +60,7 @@
// PROFILE2: ?weak@@YAXXZ:
// PROFILE2-NEXT: Hash:
// PROFILE2-NEXT: Counters: 1
-// PROFILE2-NEXT: Function count: 0
+// PROFILE2-NEXT: Function count: 2
#ifdef OBJ_1
#include <stdio.h>
diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 1b092f2518041..87cb41fc6b6b9 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -821,15 +821,10 @@ InstrProfiling::getOrCreateRegionCounters(InstrProfIncrementInst *Inc) {
PD = It->second;
}
- // Match the linkage and visibility of the name global. COFF supports using
- // comdats with internal symbols, so do that if we can.
+ // Match the linkage and visibility of the name global.
Function *Fn = Inc->getParent()->getParent();
GlobalValue::LinkageTypes Linkage = NamePtr->getLinkage();
GlobalValue::VisibilityTypes Visibility = NamePtr->getVisibility();
- if (TT.isOSBinFormatCOFF()) {
- Linkage = GlobalValue::InternalLinkage;
- Visibility = GlobalValue::DefaultVisibility;
- }
// Move the name variable to the right section. Place them in a COMDAT group
// if the associated function is a COMDAT. This will make sure that only one
@@ -838,23 +833,19 @@ 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.
+ //
+ // 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.
+ //
+ // For ELF, when not using COMDAT, put counters, data and values into a
+ // noduplicates 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 NeedComdat = needsComdatForCounter(*Fn, *M);
- if (NeedComdat) {
- if (TT.isOSBinFormatCOFF()) {
- // 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;
- }
- }
std::string DataVarName = getVarName(Inc, getInstrProfDataVarPrefix());
auto MaybeSetComdat = [=](GlobalVariable *GV) {
- // For ELF, when not using COMDAT, put counters, data and values into
- // a noduplicates COMDAT which is lowered to a zero-flag section group.
- // This allows linker GC to discard the entire group when the function
- // is discarded.
bool UseComdat = (NeedComdat || TT.isOSBinFormatELF());
if (UseComdat) {
auto GroupName = TT.isOSBinFormatCOFF() ? GV->getName() : DataVarName;
diff --git a/llvm/test/Instrumentation/InstrProfiling/linkage.ll b/llvm/test/Instrumentation/InstrProfiling/linkage.ll
index dc914f1d7e23c..bf49e6b49e30b 100644
--- a/llvm/test/Instrumentation/InstrProfiling/linkage.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/linkage.ll
@@ -28,9 +28,9 @@
; ELF: @__profd_foo = private global {{.*}} section "__llvm_prf_data", comdat, align 8
; MACHO: @__profc_foo = private global
; MACHO: @__profd_foo = private global
-; COFF: @__profc_foo = internal global
+; COFF: @__profc_foo = private global
; COFF-NOT: comdat
-; COFF: @__profd_foo = internal global
+; COFF: @__profd_foo = private global
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
@@ -40,8 +40,8 @@ define void @foo() {
; ELF: @__profd_foo_weak = weak hidden global {{.*}} section "__llvm_prf_data", comdat, align 8
; MACHO: @__profc_foo_weak = weak hidden global
; MACHO: @__profd_foo_weak = weak hidden global
-; COFF: @__profc_foo_weak = internal global
-; COFF: @__profd_foo_weak = internal global
+; COFF: @__profc_foo_weak = weak hidden global
+; COFF: @__profd_foo_weak = weak hidden global
define weak void @foo_weak() {
call void @llvm.instrprof.increment(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @__profn_foo_weak, i32 0, i32 0), i64 0, i32 1, i32 0)
ret void
@@ -51,8 +51,8 @@ define weak void @foo_weak() {
; ELF: @"__profd_linkage.ll:foo_internal" = private global {{.*}} section "__llvm_prf_data", comdat, align 8
; MACHO: @"__profc_linkage.ll:foo_internal" = private global
; MACHO: @"__profd_linkage.ll:foo_internal" = private global
-; COFF: @"__profc_linkage.ll:foo_internal" = internal global
-; COFF: @"__profd_linkage.ll:foo_internal" = internal global
+; COFF: @"__profc_linkage.ll:foo_internal" = private global
+; COFF: @"__profd_linkage.ll:foo_internal" = private global
define internal void @foo_internal() {
call void @llvm.instrprof.increment(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @"__profn_linkage.ll:foo_internal", i32 0, i32 0), i64 0, i32 1, i32 0)
ret void
@@ -62,8 +62,8 @@ define internal void @foo_internal() {
; ELF: @__profd_foo_inline = linkonce_odr hidden global {{.*}} section "__llvm_prf_data", comdat, align 8
; MACHO: @__profc_foo_inline = linkonce_odr hidden global
; MACHO: @__profd_foo_inline = linkonce_odr hidden global
-; COFF: @__profc_foo_inline = internal global{{.*}} section ".lprfc$M", align 8
-; COFF: @__profd_foo_inline = internal global{{.*}} section ".lprfd$M", align 8
+; COFF: @__profc_foo_inline = linkonce_odr hidden global{{.*}} section ".lprfc$M", align 8
+; COFF: @__profd_foo_inline = linkonce_odr hidden global{{.*}} section ".lprfd$M", 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 cbc045cf654f1..bbe59d73f479f 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($__profd_foo), align 8
-; WINDOWS: @__profc_foo = internal global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
+; WINDOWS: @__profc_foo = private global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
; MACHO: @__profd_foo = private {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
; ELF: @__profd_foo = private {{.*}}, section "__llvm_prf_data", comdat, align 8
-; WINDOWS: @__profd_foo = internal global {{.*}}, section ".lprfd$M", align 8
+; WINDOWS: @__profd_foo = private global {{.*}}, section ".lprfd$M", align 8
; ELF: @__llvm_prf_nm = private constant [{{.*}} x i8] c"{{.*}}", section "{{.*}}__llvm_prf_names", align 1
; WINDOWS: @__llvm_prf_nm = private constant [{{.*}} x i8] c"{{.*}}", section "{{.*}}lprfn$M", align 1
diff --git a/llvm/test/Instrumentation/InstrProfiling/profiling.ll b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
index 38084568aad57..64d4b98d2e6c7 100644
--- a/llvm/test/Instrumentation/InstrProfiling/profiling.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
@@ -21,8 +21,8 @@
; ELF: @__profd_foo = private {{.*}}, section "__llvm_prf_data", comdat, 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 = internal global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
-; WIN: @__profd_foo = internal {{.*}}, section ".lprfd$M", 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
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, 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 = internal global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
-; WIN: @__profd_bar = internal {{.*}}, section ".lprfd$M", 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
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, 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 = internal global [3 x i64] zeroinitializer, section ".lprfc$M", align 8
-; WIN: @__profd_baz = internal {{.*}}, section ".lprfd$M", 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
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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