Hi dexonsmith,
I don't particularly like this approach.
The change in linkage for link once symbols is needed for ELF targets.
Although the symbol is only associated once, the discarded symbols
still occupy memory. This causes duplicate count problem at runtime
because the raw profile contains multiple copies of the same data
record (see https://llvm.org/bugs/show_bug.cgi?id=23499 for details).
http://reviews.llvm.org/D10035
Files:
lib/CodeGen/CodeGenPGO.cpp
test/Profile/cxx-linkage.cpp
test/Profile/cxx-templates.cpp
Index: lib/CodeGen/CodeGenPGO.cpp
===================================================================
--- lib/CodeGen/CodeGenPGO.cpp
+++ lib/CodeGen/CodeGenPGO.cpp
@@ -66,7 +66,8 @@
else if (Linkage == llvm::GlobalValue::AvailableExternallyLinkage)
Linkage = llvm::GlobalValue::LinkOnceODRLinkage;
else if (Linkage == llvm::GlobalValue::InternalLinkage ||
- Linkage == llvm::GlobalValue::ExternalLinkage)
+ Linkage == llvm::GlobalValue::ExternalLinkage ||
+ Linkage == llvm::GlobalValue::LinkOnceODRLinkage)
Linkage = llvm::GlobalValue::PrivateLinkage;
auto *Value =
@@ -773,6 +774,8 @@
// Turn on Cold attribute for cold functions.
// FIXME: 1% is from preliminary tuning on SPEC, it may not be optimal.
Fn->addFnAttr(llvm::Attribute::Cold);
+
+ Fn->setEntryCount(FunctionCount);
}
void CodeGenPGO::emitCounterIncrement(CGBuilderTy &Builder, const Stmt *S) {
Index: test/Profile/cxx-linkage.cpp
===================================================================
--- test/Profile/cxx-linkage.cpp
+++ test/Profile/cxx-linkage.cpp
@@ -3,7 +3,7 @@
// CHECK: @__llvm_profile_name__Z3foov = private constant [7 x i8] c"_Z3foov"
// CHECK: @__llvm_profile_name__Z8foo_weakv = weak hidden constant [12 x i8]
c"_Z8foo_weakv"
// CHECK: @__llvm_profile_name_main = private constant [4 x i8] c"main"
-// CHECK: @__llvm_profile_name__Z10foo_inlinev = linkonce_odr hidden constant
[15 x i8] c"_Z10foo_inlinev"
+// CHECK: @__llvm_profile_name__Z10foo_inlinev = private constant [15 x i8]
c"_Z10foo_inlinev"
void foo(void) { }
Index: test/Profile/cxx-templates.cpp
===================================================================
--- test/Profile/cxx-templates.cpp
+++ test/Profile/cxx-templates.cpp
@@ -10,8 +10,8 @@
// RUN: FileCheck --input-file=%tuse -check-prefix=T0USE -check-prefix=ALL %s
// RUN: FileCheck --input-file=%tuse -check-prefix=T100USE -check-prefix=ALL %s
-// T0GEN: @[[T0C:__llvm_profile_counters__Z4loopILj0EEvv]] = linkonce_odr
hidden global [2 x i64] zeroinitializer
-// T100GEN: @[[T100C:__llvm_profile_counters__Z4loopILj100EEvv]] =
linkonce_odr hidden global [2 x i64] zeroinitializer
+// T0GEN: @[[T0C:__llvm_profile_counters__Z4loopILj0EEvv]] = private global [2
x i64] zeroinitializer
+// T100GEN: @[[T100C:__llvm_profile_counters__Z4loopILj100EEvv]] = private
global [2 x i64] zeroinitializer
// T0GEN-LABEL: define linkonce_odr void @_Z4loopILj0EEvv()
// T0USE-LABEL: define linkonce_odr void @_Z4loopILj0EEvv()
EMAIL PREFERENCES
http://reviews.llvm.org/settings/panel/emailpreferences/
Index: lib/CodeGen/CodeGenPGO.cpp
===================================================================
--- lib/CodeGen/CodeGenPGO.cpp
+++ lib/CodeGen/CodeGenPGO.cpp
@@ -66,7 +66,8 @@
else if (Linkage == llvm::GlobalValue::AvailableExternallyLinkage)
Linkage = llvm::GlobalValue::LinkOnceODRLinkage;
else if (Linkage == llvm::GlobalValue::InternalLinkage ||
- Linkage == llvm::GlobalValue::ExternalLinkage)
+ Linkage == llvm::GlobalValue::ExternalLinkage ||
+ Linkage == llvm::GlobalValue::LinkOnceODRLinkage)
Linkage = llvm::GlobalValue::PrivateLinkage;
auto *Value =
@@ -773,6 +774,8 @@
// Turn on Cold attribute for cold functions.
// FIXME: 1% is from preliminary tuning on SPEC, it may not be optimal.
Fn->addFnAttr(llvm::Attribute::Cold);
+
+ Fn->setEntryCount(FunctionCount);
}
void CodeGenPGO::emitCounterIncrement(CGBuilderTy &Builder, const Stmt *S) {
Index: test/Profile/cxx-linkage.cpp
===================================================================
--- test/Profile/cxx-linkage.cpp
+++ test/Profile/cxx-linkage.cpp
@@ -3,7 +3,7 @@
// CHECK: @__llvm_profile_name__Z3foov = private constant [7 x i8] c"_Z3foov"
// CHECK: @__llvm_profile_name__Z8foo_weakv = weak hidden constant [12 x i8] c"_Z8foo_weakv"
// CHECK: @__llvm_profile_name_main = private constant [4 x i8] c"main"
-// CHECK: @__llvm_profile_name__Z10foo_inlinev = linkonce_odr hidden constant [15 x i8] c"_Z10foo_inlinev"
+// CHECK: @__llvm_profile_name__Z10foo_inlinev = private constant [15 x i8] c"_Z10foo_inlinev"
void foo(void) { }
Index: test/Profile/cxx-templates.cpp
===================================================================
--- test/Profile/cxx-templates.cpp
+++ test/Profile/cxx-templates.cpp
@@ -10,8 +10,8 @@
// RUN: FileCheck --input-file=%tuse -check-prefix=T0USE -check-prefix=ALL %s
// RUN: FileCheck --input-file=%tuse -check-prefix=T100USE -check-prefix=ALL %s
-// T0GEN: @[[T0C:__llvm_profile_counters__Z4loopILj0EEvv]] = linkonce_odr hidden global [2 x i64] zeroinitializer
-// T100GEN: @[[T100C:__llvm_profile_counters__Z4loopILj100EEvv]] = linkonce_odr hidden global [2 x i64] zeroinitializer
+// T0GEN: @[[T0C:__llvm_profile_counters__Z4loopILj0EEvv]] = private global [2 x i64] zeroinitializer
+// T100GEN: @[[T100C:__llvm_profile_counters__Z4loopILj100EEvv]] = private global [2 x i64] zeroinitializer
// T0GEN-LABEL: define linkonce_odr void @_Z4loopILj0EEvv()
// T0USE-LABEL: define linkonce_odr void @_Z4loopILj0EEvv()
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