[llvm] 461a183 - [PGO][AIX] Improve dummy var retention and allow -bcdtors:csect linking.
Wael Yehia via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 21 09:33:31 PDT 2022
Author: Wael Yehia
Date: 2022-10-21T16:32:42Z
New Revision: 461a1836d3d77371bb6271fefd645897997a22b8
URL: https://github.com/llvm/llvm-project/commit/461a1836d3d77371bb6271fefd645897997a22b8
DIFF: https://github.com/llvm/llvm-project/commit/461a1836d3d77371bb6271fefd645897997a22b8.diff
LOG: [PGO][AIX] Improve dummy var retention and allow -bcdtors:csect linking.
1) Use a static array of pointer to retain the dummy vars.
2) Associate liveness of the array with that of the runtime hook variable
__llvm_profile_runtime.
3) Perform the runtime initialization through the runtime hook variable.
4) Preserve the runtime hook variable using the -u linker flag.
Reviewed By: hubert.reinterpretcast
Differential Revision: https://reviews.llvm.org/D136192
Added:
compiler-rt/test/profile/AIX/lit.local.cfg.py
compiler-rt/test/profile/AIX/shared-bexpall-pgo.c
Modified:
clang/lib/Driver/ToolChains/AIX.cpp
clang/lib/Driver/ToolChains/AIX.h
compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
compiler-rt/lib/profile/InstrProfilingRuntime.cpp
llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
llvm/test/Instrumentation/InstrProfiling/no-counters.ll
llvm/test/Instrumentation/InstrProfiling/profiling.ll
Removed:
################################################################################
diff --git a/clang/lib/Driver/ToolChains/AIX.cpp b/clang/lib/Driver/ToolChains/AIX.cpp
index 748b6a3590053..1e72f1e761e8b 100644
--- a/clang/lib/Driver/ToolChains/AIX.cpp
+++ b/clang/lib/Driver/ToolChains/AIX.cpp
@@ -13,6 +13,7 @@
#include "clang/Driver/Options.h"
#include "clang/Driver/SanitizerArgs.h"
#include "llvm/Option/ArgList.h"
+#include "llvm/ProfileData/InstrProf.h"
#include "llvm/Support/Path.h"
using AIX = clang::driver::toolchains::AIX;
@@ -348,6 +349,16 @@ void AIX::AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
llvm_unreachable("Unexpected C++ library type; only libc++ is supported.");
}
+void AIX::addProfileRTLibs(const llvm::opt::ArgList &Args,
+ llvm::opt::ArgStringList &CmdArgs) const {
+ // Add linker option -u__llvm_profile_runtime to cause runtime
+ // initialization to occur.
+ if (needsProfileRT(Args))
+ CmdArgs.push_back(Args.MakeArgString(
+ Twine("-u", llvm::getInstrProfRuntimeHookVarName())));
+ ToolChain::addProfileRTLibs(Args, CmdArgs);
+}
+
ToolChain::CXXStdlibType AIX::GetDefaultCXXStdlibType() const {
return ToolChain::CST_Libcxx;
}
diff --git a/clang/lib/Driver/ToolChains/AIX.h b/clang/lib/Driver/ToolChains/AIX.h
index c9948a65b89ab..e03aebcc3e7f0 100644
--- a/clang/lib/Driver/ToolChains/AIX.h
+++ b/clang/lib/Driver/ToolChains/AIX.h
@@ -80,6 +80,9 @@ class LLVM_LIBRARY_VISIBILITY AIX : public ToolChain {
void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,
llvm::opt::ArgStringList &CmdArgs) const override;
+ void addProfileRTLibs(const llvm::opt::ArgList &Args,
+ llvm::opt::ArgStringList &CmdArgs) const override;
+
CXXStdlibType GetDefaultCXXStdlibType() const override;
RuntimeLibType GetDefaultRuntimeLibType() const override;
diff --git a/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c b/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
index 3af61d24948e7..adf4132c6b4d6 100644
--- a/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
+++ b/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
@@ -250,23 +250,21 @@ void __llvm_profile_register_names_function(void *NamesStart,
// section exists. So for the scenario where the user objects have no such
// section (i.e. when they are compiled with -fno-profile-generate), we always
// define these zero length variables in each of the above 4 sections.
-COMPILER_RT_VISIBILITY int dummy_cnts[0] COMPILER_RT_SECTION(
+static int dummy_cnts[0] COMPILER_RT_SECTION(
COMPILER_RT_SEG INSTR_PROF_CNTS_SECT_NAME);
-COMPILER_RT_VISIBILITY int dummy_data[0] COMPILER_RT_SECTION(
+static int dummy_data[0] COMPILER_RT_SECTION(
COMPILER_RT_SEG INSTR_PROF_DATA_SECT_NAME);
-COMPILER_RT_VISIBILITY const int dummy_name[0] COMPILER_RT_SECTION(
+static const int dummy_name[0] COMPILER_RT_SECTION(
COMPILER_RT_SEG INSTR_PROF_NAME_SECT_NAME);
-COMPILER_RT_VISIBILITY int dummy_vnds[0] COMPILER_RT_SECTION(
+static int dummy_vnds[0] COMPILER_RT_SECTION(
COMPILER_RT_SEG INSTR_PROF_VNODES_SECT_NAME);
-// Create a fake reference to avoid GC'ing of the dummy variables by the linker.
-// Ideally, we create a ".ref" of each variable inside the function
-// __llvm_profile_begin_counters(), but there's no source level construct
-// that allows us to generate that.
-__attribute__((destructor)) void keep() {
- int volatile use = &dummy_cnts < &dummy_data && &dummy_name < &dummy_vnds;
- (void)use;
-}
+// To avoid GC'ing of the dummy variables by the linker, reference them in an
+// array and reference the array in the runtime registration code
+// (InstrProfilingRuntime.cpp)
+COMPILER_RT_VISIBILITY
+void *__llvm_profile_keep[] = {(void *)&dummy_cnts, (void *)&dummy_data,
+ (void *)&dummy_name, (void *)&dummy_vnds};
#endif
#endif
diff --git a/compiler-rt/lib/profile/InstrProfilingRuntime.cpp b/compiler-rt/lib/profile/InstrProfilingRuntime.cpp
index 4ea2bb263f5ac..04f761c6ca726 100644
--- a/compiler-rt/lib/profile/InstrProfilingRuntime.cpp
+++ b/compiler-rt/lib/profile/InstrProfilingRuntime.cpp
@@ -10,19 +10,23 @@ extern "C" {
#include "InstrProfiling.h"
-/* int __llvm_profile_runtime */
-COMPILER_RT_VISIBILITY int INSTR_PROF_PROFILE_RUNTIME_VAR;
+static int RegisterRuntime() {
+ __llvm_profile_initialize();
+ return 0;
}
-namespace {
-
-class RegisterRuntime {
-public:
- RegisterRuntime() {
- __llvm_profile_initialize();
- }
-};
-
-RegisterRuntime Registration;
+#ifndef _AIX
+/* int __llvm_profile_runtime */
+COMPILER_RT_VISIBILITY int INSTR_PROF_PROFILE_RUNTIME_VAR;
+static int Registration = RegisterRuntime();
+#else
+extern COMPILER_RT_VISIBILITY void *__llvm_profile_keep[];
+/* On AIX, when linking with -bcdtors:csect, the variable whose constructor does
+ * the registration needs to be explicitly kept, hence we reuse the runtime hook
+ * variable to do the registration since it'll be kept via the -u linker flag.
+ * Create a volatile reference to __llvm_profile_keep to keep the array alive.*/
+COMPILER_RT_VISIBILITY int INSTR_PROF_PROFILE_RUNTIME_VAR =
+ ((void)*(void *volatile *)__llvm_profile_keep, RegisterRuntime());
+#endif
}
diff --git a/compiler-rt/test/profile/AIX/lit.local.cfg.py b/compiler-rt/test/profile/AIX/lit.local.cfg.py
new file mode 100644
index 0000000000000..7ec27bf021e2d
--- /dev/null
+++ b/compiler-rt/test/profile/AIX/lit.local.cfg.py
@@ -0,0 +1,9 @@
+def getRoot(config):
+ if not config.parent:
+ return config
+ return getRoot(config.parent)
+
+root = getRoot(config)
+
+if root.host_os not in ['AIX']:
+ config.unsupported = True
diff --git a/compiler-rt/test/profile/AIX/shared-bexpall-pgo.c b/compiler-rt/test/profile/AIX/shared-bexpall-pgo.c
new file mode 100644
index 0000000000000..b3b865db16f32
--- /dev/null
+++ b/compiler-rt/test/profile/AIX/shared-bexpall-pgo.c
@@ -0,0 +1,14 @@
+// RUN: split-file %s %t
+// RUN: cd %t
+//
+// RUN: %clang_pgogen foo.c -c -o foo.o
+// RUN: %clang_pgogen -shared foo.o -o libfoo.so -bexpall
+// RUN: %clang_pgogen -L%t user.c libfoo.so -o user1
+// RUN: ./user1
+
+//--- foo.c
+void foo() {}
+
+//--- user.c
+void foo();
+int main() { foo(); }
diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 7d54a9b97b9a5..3af3f908ea5b2 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -1199,7 +1199,7 @@ void InstrProfiling::emitRegistration() {
bool InstrProfiling::emitRuntimeHook() {
// We expect the linker to be invoked with -u<hook_var> flag for Linux
// in which case there is no need to emit the external variable.
- if (TT.isOSLinux())
+ if (TT.isOSLinux() || TT.isOSAIX())
return false;
// If the module's provided its own runtime, we don't need to do anything.
diff --git a/llvm/test/Instrumentation/InstrProfiling/no-counters.ll b/llvm/test/Instrumentation/InstrProfiling/no-counters.ll
index 165fe493ba63b..9afaf4ff45faf 100644
--- a/llvm/test/Instrumentation/InstrProfiling/no-counters.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/no-counters.ll
@@ -2,7 +2,7 @@
; RUN: opt < %s -mtriple=x86_64-apple-macosx10.10.0 -passes=instrprof -S | FileCheck %s -check-prefixes=ALL,DARWIN
; RUN: opt < %s -mtriple=x86_64-linux-unknown -passes=instrprof -S | FileCheck %s -check-prefixes=ALL,LINUX
-; RUN: opt < %s -mtriple=powerpc64-ibm-aix-xcoff -passes=instrprof -S | FileCheck %s -check-prefixes=ALL,DARWIN
+; RUN: opt < %s -mtriple=powerpc64-ibm-aix-xcoff -passes=instrprof -S | FileCheck %s -check-prefixes=ALL,LINUX
; ALL-NOT: @__profc
; ALL-NOT: @__profd
; DARWIN: @__llvm_profile_runtime
diff --git a/llvm/test/Instrumentation/InstrProfiling/profiling.ll b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
index 95e5e0853a53f..caff611b98ccc 100644
--- a/llvm/test/Instrumentation/InstrProfiling/profiling.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
@@ -13,7 +13,7 @@
; MACHO: @__llvm_profile_runtime = external hidden global i32
; ELF_GENERIC: @__llvm_profile_runtime = external hidden global i32
; ELF-NOT: @__llvm_profile_runtime = external global i32
-; XCOFF: @__llvm_profile_runtime = external hidden global i32
+; XCOFF-NOT: @__llvm_profile_runtime = external hidden global i32
; COFF: @__llvm_profile_runtime = external hidden global i32
; ELF: $__profc_foo = comdat nodeduplicate
@@ -101,7 +101,7 @@ declare void @llvm.instrprof.increment(ptr, i64, i32, i32)
; ELF_GENERIC: @llvm.compiler.used = appending global [6 x ptr] [ptr @__llvm_profile_runtime, ptr @__profd_foo, ptr @__profd_foo_weak, ptr @"__profd_linkage.ll:foo_internal", ptr @__profd_foo_inline, ptr @__profd_foo_extern]
; MACHO: @llvm.compiler.used = appending global [6 x ptr] [ptr @__llvm_profile_runtime_user, ptr @__profd_foo, {{.*}}
; COFF: @llvm.compiler.used = appending global [6 x ptr] [ptr @__llvm_profile_runtime_user, ptr @__profd_foo, ptr @__profd_foo_weak, ptr @"__profd_linkage.ll:foo_internal", ptr @__profd_foo_inline, ptr @__profd_foo_extern]
-; XCOFF: @llvm.used = appending global [7 x ptr] [ptr @__llvm_profile_runtime_user, ptr @__profd_foo, ptr @__profd_foo_weak, ptr @"__profd_linkage.ll:foo_internal", ptr @__profd_foo_inline, ptr @__profd_foo_extern, ptr @__llvm_prf_nm]
+; XCOFF: @llvm.used = appending global [6 x ptr] [ptr @__profd_foo, ptr @__profd_foo_weak, ptr @"__profd_linkage.ll:foo_internal", ptr @__profd_foo_inline, ptr @__profd_foo_extern, ptr @__llvm_prf_nm]
; MACHO: define linkonce_odr hidden i32 @__llvm_profile_runtime_user() {{.*}} {
; MACHO: %[[REG:.*]] = load i32, ptr @__llvm_profile_runtime
@@ -112,10 +112,7 @@ declare void @llvm.instrprof.increment(ptr, i64, i32, i32)
; ELFRT-NOT: %[[REG:.*]] = load i32, ptr @__llvm_profile_runtime
; PS: define linkonce_odr hidden i32 @__llvm_profile_runtime_user() {{.*}} {
; PS: %[[REG:.*]] = load i32, ptr @__llvm_profile_runtime
-; XCOFF: define linkonce_odr hidden i32 @__llvm_profile_runtime_user() {{.*}} {
-; XCOFF: %[[REG:.*]] = load i32, ptr @__llvm_profile_runtime
-; XCOFF: ret i32 %[[REG]]
-; XCOFF: }
+; XCOFF-NOT: define .* __llvm_profile_runtime_user
; ELF_GENERIC: define internal void @__llvm_profile_register_functions() unnamed_addr {
; ELF_GENERIC-NEXT: call void @__llvm_profile_register_function(ptr @__llvm_profile_runtime)
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