[clang] [llvm] [memprof] Export __memprof_default_options_str on Darwin (PR #128920)

[Ellis Hoag via cfe-commits]

https://github.com/ellishg updated https://github.com/llvm/llvm-project/pull/128920

>From 2e1946730f7ae2473a4fc94f8918eb3d9d225d17 Mon Sep 17 00:00:00 2001
From: Ellis Hoag <ellishoag at meta.com>
Date: Wed, 26 Feb 2025 09:48:46 -0800
Subject: [PATCH 1/3] [memprof] Export __memprof_default_options_str on Darwin

---
 clang/lib/Driver/ToolChains/Darwin.cpp | 4 ++++
 clang/test/Driver/fmemprof.cpp         | 8 ++++++++
 2 files changed, 12 insertions(+)

diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index 75f126965e0ac..a2aeef4c4c475 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -1617,6 +1617,10 @@ void DarwinClang::AddLinkRuntimeLibArgs(const ArgList &Args,
     }
   }
 
+  if (Sanitize.needsMemProfRt())
+    if (hasExportSymbolDirective(Args))
+      addExportedSymbol(CmdArgs, "___memprof_default_options_str");
+
   const XRayArgs &XRay = getXRayArgs();
   if (XRay.needsXRayRt()) {
     AddLinkRuntimeLib(Args, CmdArgs, "xray");
diff --git a/clang/test/Driver/fmemprof.cpp b/clang/test/Driver/fmemprof.cpp
index 5165c4452fd57..b464320e58a94 100644
--- a/clang/test/Driver/fmemprof.cpp
+++ b/clang/test/Driver/fmemprof.cpp
@@ -17,3 +17,11 @@
 
 // RUN: not %clangxx --target=x86_64-linux-gnu -fprofile-generate -fmemory-profile-use=foo %s -### 2>&1 | FileCheck %s --check-prefix=CONFLICTWITHPGOINSTR
 // CONFLICTWITHPGOINSTR: error: invalid argument '-fmemory-profile-use=foo' not allowed with '-fprofile-generate'
+
+// Test that we export the __memprof_default_options_str on Darwin because it has WeakAnyLinkage
+// RUN: %clangxx --target=arm64-apple-ios -fmemory-profile %s -### 2>&1 | FileCheck %s -check-prefix=EXPORT-BASE --implicit-check-not=exported_symbol
+// RUN: %clangxx --target=x86_64-linux-gnu -fmemory-profile %s -### 2>&1 | FileCheck %s -check-prefix=EXPORT-BASE --implicit-check-not=exported_symbol
+// RUN: %clangxx --target=arm64-apple-ios -fmemory-profile -exported_symbols_list /dev/null %s -### 2>&1 | FileCheck %s --check-prefixes=EXPORT-BASE,EXPORT
+// FIXME: Darwin needs to link in the runtime, then we can use the regular CHECK prefix
+// EXPORT-BASE: "-cc1" {{.*}} "-fmemory-profile"
+// EXPORT: "-exported_symbol" "___memprof_default_options_str"

>From f5b85a00fd2d148bbe552ab7916954d75236ef75 Mon Sep 17 00:00:00 2001
From: Ellis Hoag <ellishoag at meta.com>
Date: Fri, 28 Feb 2025 09:01:00 -0800
Subject: [PATCH 2/3] Add helper functions and comment

---
 clang/lib/Driver/ToolChains/Darwin.cpp              |  5 ++++-
 llvm/include/llvm/ProfileData/MemProf.h             | 11 +++++++++++
 llvm/lib/Transforms/Instrumentation/MemProfiler.cpp |  7 +++----
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index a2aeef4c4c475..e67997314da36 100644
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -21,6 +21,7 @@
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/ProfileData/InstrProf.h"
+#include "llvm/ProfileData/MemProf.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/Support/Threading.h"
@@ -1619,7 +1620,9 @@ void DarwinClang::AddLinkRuntimeLibArgs(const ArgList &Args,
 
   if (Sanitize.needsMemProfRt())
     if (hasExportSymbolDirective(Args))
-      addExportedSymbol(CmdArgs, "___memprof_default_options_str");
+      addExportedSymbol(
+          CmdArgs,
+          llvm::memprof::getMemprofOptionsSymbolDarwinLinkageName().data());
 
   const XRayArgs &XRay = getXRayArgs();
   if (XRay.needsXRayRt()) {
diff --git a/llvm/include/llvm/ProfileData/MemProf.h b/llvm/include/llvm/ProfileData/MemProf.h
index da0cb47508e32..71e3faa506741 100644
--- a/llvm/include/llvm/ProfileData/MemProf.h
+++ b/llvm/include/llvm/ProfileData/MemProf.h
@@ -6,6 +6,7 @@
 #include "llvm/ADT/STLForwardCompat.h"
 #include "llvm/ADT/STLFunctionalExtras.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/ProfileData/MemProfData.inc"
 #include "llvm/Support/BLAKE3.h"
@@ -42,6 +43,16 @@ constexpr uint64_t MaximumSupportedVersion = Version3;
 // Verify that the minimum and maximum satisfy the obvious constraint.
 static_assert(MinimumSupportedVersion <= MaximumSupportedVersion);
 
+inline llvm::StringRef getMemprofOptionsSymbolDarwinLinkageName() {
+  return "___memprof_default_options_str";
+}
+
+inline llvm::StringRef getMemprofOptionsSymbolName() {
+  // Darwin linkage names are prefixed with an extra "_". See
+  // DataLayout::getGlobalPrefix().
+  return getMemprofOptionsSymbolDarwinLinkageName().drop_front();
+}
+
 enum class Meta : uint64_t {
   Start = 0,
 #define MIBEntryDef(NameTag, Name, Type) NameTag,
diff --git a/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp b/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
index 7d8bc3aa4c589..6f58a2315547a 100644
--- a/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemProfiler.cpp
@@ -568,10 +568,9 @@ void createMemprofHistogramFlagVar(Module &M) {
 void createMemprofDefaultOptionsVar(Module &M) {
   Constant *OptionsConst = ConstantDataArray::getString(
       M.getContext(), MemprofRuntimeDefaultOptions, /*AddNull=*/true);
-  GlobalVariable *OptionsVar =
-      new GlobalVariable(M, OptionsConst->getType(), /*isConstant=*/true,
-                         GlobalValue::WeakAnyLinkage, OptionsConst,
-                         "__memprof_default_options_str");
+  GlobalVariable *OptionsVar = new GlobalVariable(
+      M, OptionsConst->getType(), /*isConstant=*/true,
+      GlobalValue::WeakAnyLinkage, OptionsConst, getMemprofOptionsSymbolName());
   Triple TT(M.getTargetTriple());
   if (TT.supportsCOMDAT()) {
     OptionsVar->setLinkage(GlobalValue::ExternalLinkage);

>From 084e57b4e1f5e8f477890bc8985642a2343af3ac Mon Sep 17 00:00:00 2001
From: Ellis Hoag <ellishoag at meta.com>
Date: Fri, 28 Feb 2025 09:28:14 -0800
Subject: [PATCH 3/3] remove redundant check line

---
 clang/test/Driver/fmemprof.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/clang/test/Driver/fmemprof.cpp b/clang/test/Driver/fmemprof.cpp
index b464320e58a94..ddf2f851298f2 100644
--- a/clang/test/Driver/fmemprof.cpp
+++ b/clang/test/Driver/fmemprof.cpp
@@ -19,8 +19,7 @@
 // CONFLICTWITHPGOINSTR: error: invalid argument '-fmemory-profile-use=foo' not allowed with '-fprofile-generate'
 
 // Test that we export the __memprof_default_options_str on Darwin because it has WeakAnyLinkage
-// RUN: %clangxx --target=arm64-apple-ios -fmemory-profile %s -### 2>&1 | FileCheck %s -check-prefix=EXPORT-BASE --implicit-check-not=exported_symbol
-// RUN: %clangxx --target=x86_64-linux-gnu -fmemory-profile %s -### 2>&1 | FileCheck %s -check-prefix=EXPORT-BASE --implicit-check-not=exported_symbol
+// RUN: %clangxx --target=arm64-apple-ios -fmemory-profile %s -### 2>&1 | FileCheck %s --check-prefix=EXPORT-BASE --implicit-check-not=exported_symbol
 // RUN: %clangxx --target=arm64-apple-ios -fmemory-profile -exported_symbols_list /dev/null %s -### 2>&1 | FileCheck %s --check-prefixes=EXPORT-BASE,EXPORT
 // FIXME: Darwin needs to link in the runtime, then we can use the regular CHECK prefix
 // EXPORT-BASE: "-cc1" {{.*}} "-fmemory-profile"