[clang] 2407c13 - [AIX][PGO] Enable linux style PGO on AIX
Wael Yehia via cfe-commits
cfe-commits at lists.llvm.org
Wed May 4 21:11:42 PDT 2022
Author: Wael Yehia
Date: 2022-05-05T04:10:39Z
New Revision: 2407c13aa4a42f3a3438ae2d03fa38df0a5fd30b
URL: https://github.com/llvm/llvm-project/commit/2407c13aa4a42f3a3438ae2d03fa38df0a5fd30b
DIFF: https://github.com/llvm/llvm-project/commit/2407c13aa4a42f3a3438ae2d03fa38df0a5fd30b.diff
LOG: [AIX][PGO] Enable linux style PGO on AIX
This patch switches the PGO implementation on AIX from using the runtime
registration-based section tracking to the __start_SECNAME/__stop_SECNAME
based. In order to enable the recognition of __start_SECNAME/__stop_SECNAME
symbols in the AIX linker, the -bdbg:namedsects:ss needs to be used.
Reviewed By: jsji, MaskRay, davidxl
Differential Revision: https://reviews.llvm.org/D124857
Added:
Modified:
clang/lib/Driver/ToolChains/AIX.cpp
clang/test/Driver/aix-ld.c
compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
compiler-rt/lib/profile/InstrProfilingPlatformOther.c
llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
llvm/test/Instrumentation/InstrProfiling/platform.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 37316a792f6d12..878b84a777027c 100644
--- a/clang/lib/Driver/ToolChains/AIX.cpp
+++ b/clang/lib/Driver/ToolChains/AIX.cpp
@@ -117,7 +117,7 @@ void aix::Linker::ConstructJob(Compilation &C, const JobAction &JA,
options::OPT_fno_profile_generate, false) ||
Args.hasArg(options::OPT_fcreate_profile) ||
Args.hasArg(options::OPT_coverage))
- CmdArgs.push_back("-bdbg:namedsects");
+ CmdArgs.push_back("-bdbg:namedsects:ss");
// Specify linker output file.
assert((Output.isFilename() || Output.isNothing()) && "Invalid output.");
diff --git a/clang/test/Driver/aix-ld.c b/clang/test/Driver/aix-ld.c
index eccae132763d5e..3f4784daa1e3eb 100644
--- a/clang/test/Driver/aix-ld.c
+++ b/clang/test/Driver/aix-ld.c
@@ -664,7 +664,7 @@
// CHECK-PGO-NON-LTO: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
// CHECK-PGO-NON-LTO: "-isysroot" "[[SYSROOT:[^"]+]]"
// CHECK-PGO-NON-LTO: "{{.*}}ld{{(.exe)?}}"
-// CHECK-PGO-NON-LTO: "-bdbg:namedsects"
+// CHECK-PGO-NON-LTO: "-bdbg:namedsects:ss"
// CHECK-PGO-NON-LTO: "-b32"
// CHECK-PGO-NON-LTO: "-bpT:0x10000000" "-bpD:0x20000000"
// CHECK-PGO-NON-LTO: "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0.o"
@@ -692,7 +692,7 @@
// CHECK-PGO-LTO: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
// CHECK-PGO-LTO: "-isysroot" "[[SYSROOT:[^"]+]]"
// CHECK-PGO-LTO: "{{.*}}ld{{(.exe)?}}"
-// CHECK-PGO-LTO: "-bdbg:namedsects"
+// CHECK-PGO-LTO: "-bdbg:namedsects:ss"
// CHECK-PGO-LTO: "-b32"
// CHECK-PGO-LTO: "-bpT:0x10000000" "-bpD:0x20000000"
// CHECK-PGO-LTO: "[[SYSROOT]]/usr/lib{{/|\\\\}}crt0.o"
diff --git a/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c b/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
index 592c09b49d4b15..3af61d24948e7c 100644
--- a/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
+++ b/compiler-rt/lib/profile/InstrProfilingPlatformLinux.c
@@ -7,10 +7,13 @@
\*===----------------------------------------------------------------------===*/
#if defined(__linux__) || defined(__FreeBSD__) || defined(__Fuchsia__) || \
- (defined(__sun__) && defined(__svr4__)) || defined(__NetBSD__)
+ (defined(__sun__) && defined(__svr4__)) || defined(__NetBSD__) || \
+ defined(_AIX)
+#if !defined(_AIX)
#include <elf.h>
#include <link.h>
+#endif
#include <stdlib.h>
#include <string.h>
@@ -227,4 +230,43 @@ COMPILER_RT_VISIBILITY int __llvm_write_binary_ids(ProfDataWriter *Writer) {
}
#endif
+#if defined(_AIX)
+// Empty stubs to allow linking object files using the registration-based scheme
+COMPILER_RT_VISIBILITY
+void __llvm_profile_register_function(void *Data_) {}
+
+COMPILER_RT_VISIBILITY
+void __llvm_profile_register_names_function(void *NamesStart,
+ uint64_t NamesSize) {}
+
+// The __start_SECNAME and __stop_SECNAME symbols (for SECNAME \in
+// {"__llvm_prf_cnts", "__llvm_prf_data", "__llvm_prf_name", "__llvm_prf_vnds"})
+// are always live when linking on AIX, regardless if the .o's being linked
+// reference symbols from the profile library (for example when no files were
+// compiled with -fprofile-generate). That's because these symbols are kept
+// alive through references in constructor functions that are always live in the
+// default linking model on AIX (-bcdtors:all). The __start_SECNAME and
+// __stop_SECNAME symbols are only resolved by the linker when the SECNAME
+// 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(
+ COMPILER_RT_SEG INSTR_PROF_CNTS_SECT_NAME);
+COMPILER_RT_VISIBILITY 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(
+ COMPILER_RT_SEG INSTR_PROF_NAME_SECT_NAME);
+COMPILER_RT_VISIBILITY 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;
+}
+#endif
+
#endif
diff --git a/compiler-rt/lib/profile/InstrProfilingPlatformOther.c b/compiler-rt/lib/profile/InstrProfilingPlatformOther.c
index 7f535e6a32d6a8..c7b6e842c9fac2 100644
--- a/compiler-rt/lib/profile/InstrProfilingPlatformOther.c
+++ b/compiler-rt/lib/profile/InstrProfilingPlatformOther.c
@@ -8,7 +8,7 @@
#if !defined(__APPLE__) && !defined(__linux__) && !defined(__FreeBSD__) && \
!defined(__Fuchsia__) && !(defined(__sun__) && defined(__svr4__)) && \
- !defined(__NetBSD__) && !defined(_WIN32)
+ !defined(__NetBSD__) && !defined(_WIN32) && !defined(_AIX)
#include <stdlib.h>
#include <stdio.h>
diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 379c41ce669362..06c1b8990dbe61 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -855,7 +855,7 @@ static bool needsRuntimeRegistrationOfSectionRange(const Triple &TT) {
if (TT.isOSDarwin())
return false;
// Use linker script magic to get data/cnts/name start/end.
- if (TT.isOSLinux() || TT.isOSFreeBSD() || TT.isOSNetBSD() ||
+ if (TT.isOSAIX() || TT.isOSLinux() || TT.isOSFreeBSD() || TT.isOSNetBSD() ||
TT.isOSSolaris() || TT.isOSFuchsia() || TT.isPS4() || TT.isOSWindows())
return false;
diff --git a/llvm/test/Instrumentation/InstrProfiling/platform.ll b/llvm/test/Instrumentation/InstrProfiling/platform.ll
index e07264c478baa5..02b2c037316177 100644
--- a/llvm/test/Instrumentation/InstrProfiling/platform.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/platform.ll
@@ -50,7 +50,7 @@ declare void @llvm.instrprof.increment(i8*, i64, i32, i32)
; SOLARIS-NOT: define internal void @__llvm_profile_register_functions
; PS4-NOT: define internal void @__llvm_profile_register_functions
; WINDOWS-NOT: define internal void @__llvm_profile_register_functions
-; AIX: define internal void @__llvm_profile_register_functions
+; AIX-NOT: define internal void @__llvm_profile_register_functions
;; PR38340: When dynamic registration is used, we had a bug where we'd register
;; something that's not a __profd_* variable.
@@ -61,4 +61,4 @@ declare void @llvm.instrprof.increment(i8*, i64, i32, i32)
; SOLARIS-NOT: define internal void @__llvm_profile_init
; PS4-NOT: define internal void @__llvm_profile_init
; WINDOWS-NOT: define internal void @__llvm_profile_init
-; AIX: define internal void @__llvm_profile_init
+; AIX-NOT: define internal void @__llvm_profile_init
diff --git a/llvm/test/Instrumentation/InstrProfiling/profiling.ll b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
index 8138552b42d591..b72a8bece714fa 100644
--- a/llvm/test/Instrumentation/InstrProfiling/profiling.ll
+++ b/llvm/test/Instrumentation/InstrProfiling/profiling.ll
@@ -119,9 +119,4 @@ declare void @llvm.instrprof.increment(i8*, i64, i32, i32)
; ELF_GENERIC-NEXT: ret void
; ELF_GENERIC-NEXT: }
-; XCOFF: define internal void @__llvm_profile_register_functions() unnamed_addr {
-; XCOFF-NEXT: call void @__llvm_profile_register_function(i8* bitcast ({ i64, i64, i64, i8*, i8*, i32, [{{.*}} x i16] }* @__profd_foo to i8*))
-; XCOFF-NEXT: call void @__llvm_profile_register_function(i8* bitcast ({ i64, i64, i64, i8*, i8*, i32, [{{.*}} x i16] }* @__profd_foo_weak to i8*))
-; XCOFF: call void @__llvm_profile_register_names_function(i8* getelementptr inbounds {{.*}} @__llvm_prf_nm
-; XCOFF-NEXT: ret void
-; XCOFF-NEXT: }
+; XCOFF-NOT: internal void @__llvm_profile_register_functions()
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