[clang] f50aef7 - Revert "[InstrProfiling] Don't generate __llvm_profile_runtime_user"
Hans Wennborg via cfe-commits
cfe-commits at lists.llvm.org
Fri Mar 12 04:55:27 PST 2021
Author: Hans Wennborg
Date: 2021-03-12T13:53:46+01:00
New Revision: f50aef745c3ba981f3d0bf118b809d0c3880a490
URL: https://github.com/llvm/llvm-project/commit/f50aef745c3ba981f3d0bf118b809d0c3880a490
DIFF: https://github.com/llvm/llvm-project/commit/f50aef745c3ba981f3d0bf118b809d0c3880a490.diff
LOG: Revert "[InstrProfiling] Don't generate __llvm_profile_runtime_user"
This broke the check-profile tests on Mac, see comment on the code
review.
> This is no longer needed, we can add __llvm_profile_runtime directly
> to llvm.compiler.used or llvm.used to achieve the same effect.
>
> Differential Revision: https://reviews.llvm.org/D98325
This reverts commit c7712087cbb505d324e1149fa224f607c91a8c6a.
Also reverting the dependent follow-up commit:
Revert "[InstrProfiling] Generate runtime hook for ELF platforms"
> When using -fprofile-list to selectively apply instrumentation only
> to certain files or functions, we may end up with a binary that doesn't
> have any counters in the case where no files were selected. However,
> because on Linux and Fuchsia, we pass -u__llvm_profile_runtime, the
> runtime would still be pulled in and incur some non-trivial overhead,
> especially in the case when the continuous or runtime counter relocation
> mode is being used. A better way would be to pull in the profile runtime
> only when needed by declaring the __llvm_profile_runtime symbol in the
> translation unit only when needed.
>
> This approach was already used prior to 9a041a75221ca, but we changed it
> to always generate the __llvm_profile_runtime due to a TAPI limitation.
> Since TAPI is only used on Mach-O platforms, we could use the early
> emission of __llvm_profile_runtime there, and on other platforms we
> could change back to the earlier approach where the symbol is generated
> later only when needed. We can stop passing -u__llvm_profile_runtime to
> the linker on Linux and Fuchsia since the generated undefined symbol in
> each translation unit that needed it serves the same purpose.
>
> Differential Revision: https://reviews.llvm.org/D98061
This reverts commit 87fd09b25f8892e07b7ba11525baa9c3ec3e5d3f.
Added:
Modified:
clang/docs/UsersManual.rst
clang/lib/Driver/ToolChains/Fuchsia.cpp
clang/lib/Driver/ToolChains/Fuchsia.h
clang/lib/Driver/ToolChains/Linux.cpp
clang/lib/Driver/ToolChains/Linux.h
clang/test/Driver/coverage-ld.c
clang/test/Driver/fuchsia.c
llvm/include/llvm/ProfileData/InstrProf.h
llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
llvm/test/Instrumentation/InstrProfiling/linkage.ll
llvm/test/Instrumentation/InstrProfiling/profiling.ll
Removed:
################################################################################
diff --git a/clang/docs/UsersManual.rst b/clang/docs/UsersManual.rst
index 8a369c88c2a5..28de4e3aac6f 100644
--- a/clang/docs/UsersManual.rst
+++ b/clang/docs/UsersManual.rst
@@ -2301,14 +2301,6 @@ In these cases, you can use the flag ``-fno-profile-instr-generate`` (or
Note that these flags should appear after the corresponding profile
flags to have an effect.
-.. note::
-
- When none of the translation units inside a binary is instrumented, in the
- case of ELF and COFF binary format the profile runtime will not be linked
- into the binary and no profile will be produced, while in the case of Mach-O
- the profile runtime will be linked and profile will be produced but there
- will not be any counters.
-
Instrumenting only selected files or functions
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Driver/ToolChains/Fuchsia.cpp b/clang/lib/Driver/ToolChains/Fuchsia.cpp
index 4b27a102f218..8e086010a984 100644
--- a/clang/lib/Driver/ToolChains/Fuchsia.cpp
+++ b/clang/lib/Driver/ToolChains/Fuchsia.cpp
@@ -394,3 +394,13 @@ SanitizerMask Fuchsia::getDefaultSanitizers() const {
}
return Res;
}
+
+void Fuchsia::addProfileRTLibs(const llvm::opt::ArgList &Args,
+ llvm::opt::ArgStringList &CmdArgs) const {
+ // Add linker option -u__llvm_profile_runtime to cause runtime
+ // initialization module to be linked in.
+ if (needsProfileRT(Args))
+ CmdArgs.push_back(Args.MakeArgString(
+ Twine("-u", llvm::getInstrProfRuntimeHookVarName())));
+ ToolChain::addProfileRTLibs(Args, CmdArgs);
+}
diff --git a/clang/lib/Driver/ToolChains/Fuchsia.h b/clang/lib/Driver/ToolChains/Fuchsia.h
index 1a0263ce3393..07adf9b7101d 100644
--- a/clang/lib/Driver/ToolChains/Fuchsia.h
+++ b/clang/lib/Driver/ToolChains/Fuchsia.h
@@ -71,6 +71,9 @@ class LLVM_LIBRARY_VISIBILITY Fuchsia : public ToolChain {
SanitizerMask getSupportedSanitizers() const override;
SanitizerMask getDefaultSanitizers() const override;
+ void addProfileRTLibs(const llvm::opt::ArgList &Args,
+ llvm::opt::ArgStringList &CmdArgs) const override;
+
RuntimeLibType
GetRuntimeLibType(const llvm::opt::ArgList &Args) const override;
CXXStdlibType
diff --git a/clang/lib/Driver/ToolChains/Linux.cpp b/clang/lib/Driver/ToolChains/Linux.cpp
index 5f5b069fe2df..ad98013dd4f0 100644
--- a/clang/lib/Driver/ToolChains/Linux.cpp
+++ b/clang/lib/Driver/ToolChains/Linux.cpp
@@ -925,6 +925,16 @@ SanitizerMask Linux::getSupportedSanitizers() const {
return Res;
}
+void Linux::addProfileRTLibs(const llvm::opt::ArgList &Args,
+ llvm::opt::ArgStringList &CmdArgs) const {
+ // Add linker option -u__llvm_profile_runtime to cause runtime
+ // initialization module to be linked in.
+ if (needsProfileRT(Args))
+ CmdArgs.push_back(Args.MakeArgString(
+ Twine("-u", llvm::getInstrProfRuntimeHookVarName())));
+ ToolChain::addProfileRTLibs(Args, CmdArgs);
+}
+
llvm::DenormalMode
Linux::getDefaultDenormalModeForType(const llvm::opt::ArgList &DriverArgs,
const JobAction &JA,
diff --git a/clang/lib/Driver/ToolChains/Linux.h b/clang/lib/Driver/ToolChains/Linux.h
index 605ba5431b81..05e01a208456 100644
--- a/clang/lib/Driver/ToolChains/Linux.h
+++ b/clang/lib/Driver/ToolChains/Linux.h
@@ -43,6 +43,8 @@ class LLVM_LIBRARY_VISIBILITY Linux : public Generic_ELF {
bool isNoExecStackDefault() const override;
bool IsMathErrnoDefault() const override;
SanitizerMask getSupportedSanitizers() const override;
+ void addProfileRTLibs(const llvm::opt::ArgList &Args,
+ llvm::opt::ArgStringList &CmdArgs) const override;
std::string computeSysRoot() const override;
std::string getDynamicLinker(const llvm::opt::ArgList &Args) const override;
diff --git a/clang/test/Driver/coverage-ld.c b/clang/test/Driver/coverage-ld.c
index fd13f7759609..c15531fa05e9 100644
--- a/clang/test/Driver/coverage-ld.c
+++ b/clang/test/Driver/coverage-ld.c
@@ -12,7 +12,9 @@
// RUN: --sysroot=%S/Inputs/basic_linux_tree \
// RUN: | FileCheck --check-prefix=CHECK-LINUX-I386 %s
//
+// CHECK-LINUX-I386-NOT: "-u__llvm_profile_runtime"
// CHECK-LINUX-I386: /Inputs/resource_dir{{/|\\\\}}lib{{/|\\\\}}linux{{/|\\\\}}libclang_rt.profile-i386.a"
+// CHECK-LINUX-I386-NOT: "-u__llvm_profile_runtime"
// CHECK-LINUX-I386: "-lc"
//
// RUN: %clang -no-canonical-prefixes %s -### -o %t.o 2>&1 \
diff --git a/clang/test/Driver/fuchsia.c b/clang/test/Driver/fuchsia.c
index 9b03fea55a3a..5d3b4c8d9fe3 100644
--- a/clang/test/Driver/fuchsia.c
+++ b/clang/test/Driver/fuchsia.c
@@ -249,6 +249,7 @@
// RUN: -fuse-ld=lld 2>&1 \
// RUN: | FileCheck %s -check-prefix=CHECK-PROFRT-AARCH64
// CHECK-PROFRT-AARCH64: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-PROFRT-AARCH64: "-u__llvm_profile_runtime"
// CHECK-PROFRT-AARCH64: "[[RESOURCE_DIR]]{{/|\\\\}}lib{{/|\\\\}}aarch64-fuchsia{{/|\\\\}}libclang_rt.profile.a"
// RUN: %clang %s -### --target=x86_64-fuchsia \
@@ -257,4 +258,5 @@
// RUN: -fuse-ld=lld 2>&1 \
// RUN: | FileCheck %s -check-prefix=CHECK-PROFRT-X86_64
// CHECK-PROFRT-X86_64: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-PROFRT-X86_64: "-u__llvm_profile_runtime"
// CHECK-PROFRT-X86_64: "[[RESOURCE_DIR]]{{/|\\\\}}lib{{/|\\\\}}x86_64-fuchsia{{/|\\\\}}libclang_rt.profile.a"
diff --git a/llvm/include/llvm/ProfileData/InstrProf.h b/llvm/include/llvm/ProfileData/InstrProf.h
index 1ceab4ff3dc3..4a2cebe03f07 100644
--- a/llvm/include/llvm/ProfileData/InstrProf.h
+++ b/llvm/include/llvm/ProfileData/InstrProf.h
@@ -149,6 +149,12 @@ inline StringRef getInstrProfRuntimeHookVarName() {
return INSTR_PROF_QUOTE(INSTR_PROF_PROFILE_RUNTIME_VAR);
}
+/// Return the name of the compiler generated function that references the
+/// runtime hook variable. The function is a weak global.
+inline StringRef getInstrProfRuntimeHookVarUseFuncName() {
+ return "__llvm_profile_runtime_user";
+}
+
inline StringRef getInstrProfCounterBiasVarName() {
return "__llvm_profile_counter_bias";
}
diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 998a8b9235c7..bdb182403041 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -543,10 +543,8 @@ bool InstrProfiling::run(
UsedVars.clear();
TT = Triple(M.getTargetTriple());
- bool MadeChange = false;
- // Emit the runtime hook even if no counters are present in Mach-O.
- if (TT.isOSBinFormatMachO())
- MadeChange = emitRuntimeHook();
+ // Emit the runtime hook even if no counters are present.
+ bool MadeChange = emitRuntimeHook();
// Improve compile time by avoiding linear scans when there is no work.
GlobalVariable *CoverageNamesVar =
@@ -586,8 +584,6 @@ bool InstrProfiling::run(
emitVNodes();
emitNameData();
emitRegistration();
- if (!TT.isOSBinFormatMachO())
- emitRuntimeHook();
emitUses();
emitInitialization();
return true;
@@ -1062,6 +1058,11 @@ void InstrProfiling::emitRegistration() {
}
bool InstrProfiling::emitRuntimeHook() {
+ // We expect the linker to be invoked with -u<hook_var> flag for Linux or
+ // Fuchsia, in which case there is no need to emit the user function.
+ if (TT.isOSLinux() || TT.isOSFuchsia())
+ return false;
+
// If the module's provided its own runtime, we don't need to do anything.
if (M->getGlobalVariable(getInstrProfRuntimeHookVarName()))
return false;
@@ -1072,8 +1073,23 @@ bool InstrProfiling::emitRuntimeHook() {
new GlobalVariable(*M, Int32Ty, false, GlobalValue::ExternalLinkage,
nullptr, getInstrProfRuntimeHookVarName());
+ // Make a function that uses it.
+ auto *User = Function::Create(FunctionType::get(Int32Ty, false),
+ GlobalValue::LinkOnceODRLinkage,
+ getInstrProfRuntimeHookVarUseFuncName(), M);
+ User->addFnAttr(Attribute::NoInline);
+ if (Options.NoRedZone)
+ User->addFnAttr(Attribute::NoRedZone);
+ User->setVisibility(GlobalValue::HiddenVisibility);
+ if (TT.supportsCOMDAT())
+ User->setComdat(M->getOrInsertComdat(User->getName()));
+
+ IRBuilder<> IRB(BasicBlock::Create(M->getContext(), "", User));
+ auto *Load = IRB.CreateLoad(Int32Ty, Var);
+ IRB.CreateRet(Load);
+
// Mark the user variable as used so that it isn't stripped out.
- CompilerUsedVars.push_back(Var);
+ CompilerUsedVars.push_back(User);
return true;
}
diff --git a/llvm/test/Instrumentation/InstrProfiling/linkage.ll b/llvm/test/Instrumentation/InstrProfiling/linkage.ll
index 81ba4d3c90d6..8de6a2ec6f0b 100644
--- a/llvm/test/Instrumentation/InstrProfiling/linkage.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/linkage.ll
@@ -10,6 +10,7 @@
; RUN: opt < %s -mtriple=x86_64-pc-win32-coff -passes=instrprof -S | FileCheck %s --check-prefixes=COFF
; MACHO: @__llvm_profile_runtime = external global i32
+; ELF-NOT: @__llvm_profile_runtime = external global i32
; ELF: $__profd_foo = comdat noduplicates
; ELF: $__profd_foo_weak = comdat noduplicates
@@ -80,3 +81,11 @@ define available_externally void @foo_extern() {
}
declare void @llvm.instrprof.increment(i8*, i64, i32, i32)
+
+; MACHO: define linkonce_odr hidden i32 @__llvm_profile_runtime_user() {{.*}} {
+; MACHO: %[[REG:.*]] = load i32, i32* @__llvm_profile_runtime
+; MACHO: ret i32 %[[REG]]
+; MACHO: }
+; COFF: define linkonce_odr hidden i32 @__llvm_profile_runtime_user() {{.*}} comdat {
+; ELF-NOT: define linkonce_odr hidden i32 @__llvm_profile_runtime_user() {{.*}} {
+; ELF-NOT: %[[REG:.*]] = load i32, i32* @__llvm_profile_runtime
diff --git a/llvm/test/Instrumentation/InstrProfiling/profiling.ll b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
index 76d319d2e6b9..44262ddf39ee 100644
--- a/llvm/test/Instrumentation/InstrProfiling/profiling.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
@@ -1,11 +1,14 @@
; RUN: opt < %s -mtriple=x86_64 -passes=instrprof -S | FileCheck %s --check-prefixes=CHECK,ELF,ELF_GENERIC
; RUN: opt < %s -mtriple=x86_64-linux -passes=instrprof -S | FileCheck %s --check-prefixes=CHECK,ELF_LINUX
; RUN: opt < %s -mtriple=x86_64-apple-macosx10.10.0 -passes=instrprof -S | FileCheck %s --check-prefixes=CHECK,MACHO
-; RUN: opt < %s -mtriple=x86_64-windows -passes=instrprof -S | FileCheck %s --check-prefixes=CHECK,COFF
+; RUN: opt < %s -mtriple=x86_64-windows -passes=instrprof -S | FileCheck %s --check-prefixes=CHECK,WIN
; RUN: opt < %s -mtriple=x86_64-apple-macosx10.10.0 -instrprof -S | FileCheck %s
+; ELF_GENERIC: @__llvm_profile_runtime = external global i32
+; ELF_LINUX-NOT: @__llvm_profile_runtime
; MACHO: @__llvm_profile_runtime = external global i32
+; WIN: @__llvm_profile_runtime = external global i32
@__profn_foo = hidden constant [3 x i8] c"foo"
; CHECK-NOT: __profn_foo
@@ -18,8 +21,8 @@
; ELF: @__profd_foo = hidden {{.*}}, section "__llvm_prf_data", comdat, align 8
; MACHO: @__profc_foo = hidden global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
; MACHO: @__profd_foo = hidden {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
-; COFF: @__profc_foo = internal global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
-; COFF: @__profd_foo = internal {{.*}}, section ".lprfd$M", align 8
+; WIN: @__profc_foo = internal global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
+; WIN: @__profd_foo = internal {{.*}}, section ".lprfd$M", align 8
define void @foo() {
call void @llvm.instrprof.increment(i8* getelementptr inbounds ([3 x i8], [3 x i8]* @__profn_foo, i32 0, i32 0), i64 0, i32 1, i32 0)
ret void
@@ -29,8 +32,8 @@ define void @foo() {
; ELF: @__profd_bar = hidden {{.*}}, section "__llvm_prf_data", comdat, align 8
; MACHO: @__profc_bar = hidden global [1 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
; MACHO: @__profd_bar = hidden {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
-; COFF: @__profc_bar = internal global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
-; COFF: @__profd_bar = internal {{.*}}, section ".lprfd$M", align 8
+; WIN: @__profc_bar = internal global [1 x i64] zeroinitializer, section ".lprfc$M", align 8
+; WIN: @__profd_bar = internal {{.*}}, section ".lprfd$M", align 8
define void @bar() {
call void @llvm.instrprof.increment(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @__profn_bar, i32 0, i32 0), i64 0, i32 1, i32 0)
ret void
@@ -40,8 +43,8 @@ define void @bar() {
; ELF: @__profd_baz = hidden {{.*}}, section "__llvm_prf_data", comdat, align 8
; MACHO: @__profc_baz = hidden global [3 x i64] zeroinitializer, section "__DATA,__llvm_prf_cnts", align 8
; MACHO: @__profd_baz = hidden {{.*}}, section "__DATA,__llvm_prf_data,regular,live_support", align 8
-; COFF: @__profc_baz = internal global [3 x i64] zeroinitializer, section ".lprfc$M", align 8
-; COFF: @__profd_baz = internal {{.*}}, section ".lprfd$M", align 8
+; WIN: @__profc_baz = internal global [3 x i64] zeroinitializer, section ".lprfc$M", align 8
+; WIN: @__profd_baz = internal {{.*}}, section ".lprfd$M", align 8
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)
@@ -51,12 +54,9 @@ define void @baz() {
declare void @llvm.instrprof.increment(i8*, i64, i32, i32)
-; ELF: @__llvm_profile_runtime = external global i32
-; COFF: @__llvm_profile_runtime = external global i32
-
-; ELF: @llvm.compiler.used = appending global {{.*}} @__profd_foo {{.*}} @__profd_bar {{.*}} @__profd_baz {{.*}} @__llvm_profile_runtime
-; MACHO: @llvm.used = appending global {{.*}} @__llvm_profile_runtime {{.*}} @__profd_foo {{.*}} @__profd_bar {{.*}} @__profd_baz
-; COFF: @llvm.used = appending global {{.*}} @__profd_foo {{.*}} @__profd_bar {{.*}} @__profd_baz {{.*}} @__llvm_profile_runtime
+; ELF: @llvm.compiler.used = appending global {{.*}} @__llvm_profile_runtime_user {{.*}} @__profd_foo {{.*}} @__profd_bar {{.*}} @__profd_baz
+; MACHO: @llvm.used = appending global {{.*}} @__llvm_profile_runtime_user {{.*}} @__profd_foo {{.*}} @__profd_bar {{.*}} @__profd_baz
+; WIN: @llvm.used = appending global {{.*}} @__llvm_profile_runtime_user {{.*}} @__profd_foo {{.*}} @__profd_bar {{.*}} @__profd_baz
; ELF_GENERIC: define internal void @__llvm_profile_register_functions() unnamed_addr {
; ELF_GENERIC-NEXT: call void @__llvm_profile_register_function(i8* bitcast ({ i64, i64, i64*, i8*, i8*, i32, [2 x i16] }* @__profd_foo to i8*))
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