[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
https://github.com/HighW4y2H3ll updated
https://github.com/llvm/llvm-project/pull/145652
>From 9a29dd6fa3f28bf507f047a22597f8510bd096b3 Mon Sep 17 00:00:00 2001
From: h2h
Date: Tue, 24 Jun 2025 23:24:32 -0700
Subject: [PATCH 01/12] [Clang] Allow vanilla C function symbol name to be used
in __attribute__((alias)) when -funique-internal-linkage-names is specified
---
clang/lib/CodeGen/CodeGenModule.cpp | 48 +--
.../unique-internal-linkage-names-alias.c | 10
2 files changed, 54 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CodeGen/unique-internal-linkage-names-alias.c
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+ GV->getName().contains(llvm::FunctionSamples::UniqSuffix)) {
+if (llvm::GlobalValue *GVDef =
+getModule().getNamedValue(D->getName())) {
+ GVDef->replaceAllUsesWith(GV);
+}
+ }
+}
+ }
+
// Already emitted.
if (!GV->isDeclaration())
return;
diff --git a/clang/test/CodeGen/unique-internal-linkage-names-alias.c
b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
new file mode 100644
index 0..14bfea08367d3
--- /dev/null
+++ b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
@@ -0,0 +1,10 @@
[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
https://github.com/HighW4y2H3ll updated
https://github.com/llvm/llvm-project/pull/145652
>From 9a29dd6fa3f28bf507f047a22597f8510bd096b3 Mon Sep 17 00:00:00 2001
From: h2h
Date: Tue, 24 Jun 2025 23:24:32 -0700
Subject: [PATCH 01/11] [Clang] Allow vanilla C function symbol name to be used
in __attribute__((alias)) when -funique-internal-linkage-names is specified
---
clang/lib/CodeGen/CodeGenModule.cpp | 48 +--
.../unique-internal-linkage-names-alias.c | 10
2 files changed, 54 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CodeGen/unique-internal-linkage-names-alias.c
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+ GV->getName().contains(llvm::FunctionSamples::UniqSuffix)) {
+if (llvm::GlobalValue *GVDef =
+getModule().getNamedValue(D->getName())) {
+ GVDef->replaceAllUsesWith(GV);
+}
+ }
+}
+ }
+
// Already emitted.
if (!GV->isDeclaration())
return;
diff --git a/clang/test/CodeGen/unique-internal-linkage-names-alias.c
b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
new file mode 100644
index 0..14bfea08367d3
--- /dev/null
+++ b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
@@ -0,0 +1,10 @@
[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
https://github.com/HighW4y2H3ll updated
https://github.com/llvm/llvm-project/pull/145652
>From 9a29dd6fa3f28bf507f047a22597f8510bd096b3 Mon Sep 17 00:00:00 2001
From: h2h
Date: Tue, 24 Jun 2025 23:24:32 -0700
Subject: [PATCH 01/10] [Clang] Allow vanilla C function symbol name to be used
in __attribute__((alias)) when -funique-internal-linkage-names is specified
---
clang/lib/CodeGen/CodeGenModule.cpp | 48 +--
.../unique-internal-linkage-names-alias.c | 10
2 files changed, 54 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CodeGen/unique-internal-linkage-names-alias.c
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+ GV->getName().contains(llvm::FunctionSamples::UniqSuffix)) {
+if (llvm::GlobalValue *GVDef =
+getModule().getNamedValue(D->getName())) {
+ GVDef->replaceAllUsesWith(GV);
+}
+ }
+}
+ }
+
// Already emitted.
if (!GV->isDeclaration())
return;
diff --git a/clang/test/CodeGen/unique-internal-linkage-names-alias.c
b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
new file mode 100644
index 0..14bfea08367d3
--- /dev/null
+++ b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
@@ -0,0 +1,10 @@
[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
https://github.com/HighW4y2H3ll updated
https://github.com/llvm/llvm-project/pull/145652
>From 9a29dd6fa3f28bf507f047a22597f8510bd096b3 Mon Sep 17 00:00:00 2001
From: h2h
Date: Tue, 24 Jun 2025 23:24:32 -0700
Subject: [PATCH 1/9] [Clang] Allow vanilla C function symbol name to be used
in __attribute__((alias)) when -funique-internal-linkage-names is specified
---
clang/lib/CodeGen/CodeGenModule.cpp | 48 +--
.../unique-internal-linkage-names-alias.c | 10
2 files changed, 54 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CodeGen/unique-internal-linkage-names-alias.c
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+ GV->getName().contains(llvm::FunctionSamples::UniqSuffix)) {
+if (llvm::GlobalValue *GVDef =
+getModule().getNamedValue(D->getName())) {
+ GVDef->replaceAllUsesWith(GV);
+}
+ }
+}
+ }
+
// Already emitted.
if (!GV->isDeclaration())
return;
diff --git a/clang/test/CodeGen/unique-internal-linkage-names-alias.c
b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
new file mode 100644
index 0..14bfea08367d3
--- /dev/null
+++ b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
@@ -0,0 +1,10 @@
+
[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
github-actions[bot] wrote:
:warning: C/C++ code formatter, clang-format found issues in your code.
:warning:
You can test this locally with the following command:
``bash
git-clang-format --diff HEAD~1 HEAD --extensions h,c,cpp --
clang/test/CodeGen/unique-internal-linkage-names-alias.c
clang/lib/CodeGen/CGCall.cpp clang/lib/CodeGen/CodeGenModule.cpp
clang/lib/CodeGen/CodeGenModule.h
``
View the diff from clang-format here.
``diff
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index adc43f234..f327a6b65 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -7721,7 +7721,8 @@ void CodeGenModule::FixupMaybeInlineFunctions() {
unsigned long sz = 0;
while (sz != DeferredMaybeInlineFunctions.size()) {
sz = DeferredMaybeInlineFunctions.size();
-for (auto I = DeferredMaybeInlineFunctions.begin(); I !=
DeferredMaybeInlineFunctions.end();) {
+for (auto I = DeferredMaybeInlineFunctions.begin();
+ I != DeferredMaybeInlineFunctions.end();) {
const auto *D = cast(I->first.getDecl());
auto *GA = GetGlobalValue(D->getName());
StringRef MangledName = getMangledName(I->first);
``
https://github.com/llvm/llvm-project/pull/145652
___
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[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
https://github.com/HighW4y2H3ll updated
https://github.com/llvm/llvm-project/pull/145652
>From 9a29dd6fa3f28bf507f047a22597f8510bd096b3 Mon Sep 17 00:00:00 2001
From: h2h
Date: Tue, 24 Jun 2025 23:24:32 -0700
Subject: [PATCH 1/7] [Clang] Allow vanilla C function symbol name to be used
in __attribute__((alias)) when -funique-internal-linkage-names is specified
---
clang/lib/CodeGen/CodeGenModule.cpp | 48 +--
.../unique-internal-linkage-names-alias.c | 10
2 files changed, 54 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CodeGen/unique-internal-linkage-names-alias.c
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+ GV->getName().contains(llvm::FunctionSamples::UniqSuffix)) {
+if (llvm::GlobalValue *GVDef =
+getModule().getNamedValue(D->getName())) {
+ GVDef->replaceAllUsesWith(GV);
+}
+ }
+}
+ }
+
// Already emitted.
if (!GV->isDeclaration())
return;
diff --git a/clang/test/CodeGen/unique-internal-linkage-names-alias.c
b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
new file mode 100644
index 0..14bfea08367d3
--- /dev/null
+++ b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
@@ -0,0 +1,10 @@
+
[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
https://github.com/HighW4y2H3ll updated
https://github.com/llvm/llvm-project/pull/145652
>From 9a29dd6fa3f28bf507f047a22597f8510bd096b3 Mon Sep 17 00:00:00 2001
From: h2h
Date: Tue, 24 Jun 2025 23:24:32 -0700
Subject: [PATCH 1/6] [Clang] Allow vanilla C function symbol name to be used
in __attribute__((alias)) when -funique-internal-linkage-names is specified
---
clang/lib/CodeGen/CodeGenModule.cpp | 48 +--
.../unique-internal-linkage-names-alias.c | 10
2 files changed, 54 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CodeGen/unique-internal-linkage-names-alias.c
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+ GV->getName().contains(llvm::FunctionSamples::UniqSuffix)) {
+if (llvm::GlobalValue *GVDef =
+getModule().getNamedValue(D->getName())) {
+ GVDef->replaceAllUsesWith(GV);
+}
+ }
+}
+ }
+
// Already emitted.
if (!GV->isDeclaration())
return;
diff --git a/clang/test/CodeGen/unique-internal-linkage-names-alias.c
b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
new file mode 100644
index 0..14bfea08367d3
--- /dev/null
+++ b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
@@ -0,0 +1,10 @@
+
[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
https://github.com/HighW4y2H3ll updated
https://github.com/llvm/llvm-project/pull/145652
>From 9a29dd6fa3f28bf507f047a22597f8510bd096b3 Mon Sep 17 00:00:00 2001
From: h2h
Date: Tue, 24 Jun 2025 23:24:32 -0700
Subject: [PATCH 1/5] [Clang] Allow vanilla C function symbol name to be used
in __attribute__((alias)) when -funique-internal-linkage-names is specified
---
clang/lib/CodeGen/CodeGenModule.cpp | 48 +--
.../unique-internal-linkage-names-alias.c | 10
2 files changed, 54 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CodeGen/unique-internal-linkage-names-alias.c
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+ GV->getName().contains(llvm::FunctionSamples::UniqSuffix)) {
+if (llvm::GlobalValue *GVDef =
+getModule().getNamedValue(D->getName())) {
+ GVDef->replaceAllUsesWith(GV);
+}
+ }
+}
+ }
+
// Already emitted.
if (!GV->isDeclaration())
return;
diff --git a/clang/test/CodeGen/unique-internal-linkage-names-alias.c
b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
new file mode 100644
index 0..14bfea08367d3
--- /dev/null
+++ b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
@@ -0,0 +1,10 @@
+
[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
https://github.com/HighW4y2H3ll updated
https://github.com/llvm/llvm-project/pull/145652
>From 9a29dd6fa3f28bf507f047a22597f8510bd096b3 Mon Sep 17 00:00:00 2001
From: h2h
Date: Tue, 24 Jun 2025 23:24:32 -0700
Subject: [PATCH 1/4] [Clang] Allow vanilla C function symbol name to be used
in __attribute__((alias)) when -funique-internal-linkage-names is specified
---
clang/lib/CodeGen/CodeGenModule.cpp | 48 +--
.../unique-internal-linkage-names-alias.c | 10
2 files changed, 54 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CodeGen/unique-internal-linkage-names-alias.c
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+ GV->getName().contains(llvm::FunctionSamples::UniqSuffix)) {
+if (llvm::GlobalValue *GVDef =
+getModule().getNamedValue(D->getName())) {
+ GVDef->replaceAllUsesWith(GV);
+}
+ }
+}
+ }
+
// Already emitted.
if (!GV->isDeclaration())
return;
diff --git a/clang/test/CodeGen/unique-internal-linkage-names-alias.c
b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
new file mode 100644
index 0..14bfea08367d3
--- /dev/null
+++ b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
@@ -0,0 +1,10 @@
+
[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
https://github.com/HighW4y2H3ll updated
https://github.com/llvm/llvm-project/pull/145652
>From 9a29dd6fa3f28bf507f047a22597f8510bd096b3 Mon Sep 17 00:00:00 2001
From: h2h
Date: Tue, 24 Jun 2025 23:24:32 -0700
Subject: [PATCH 1/3] [Clang] Allow vanilla C function symbol name to be used
in __attribute__((alias)) when -funique-internal-linkage-names is specified
---
clang/lib/CodeGen/CodeGenModule.cpp | 48 +--
.../unique-internal-linkage-names-alias.c | 10
2 files changed, 54 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CodeGen/unique-internal-linkage-names-alias.c
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+ GV->getName().contains(llvm::FunctionSamples::UniqSuffix)) {
+if (llvm::GlobalValue *GVDef =
+getModule().getNamedValue(D->getName())) {
+ GVDef->replaceAllUsesWith(GV);
+}
+ }
+}
+ }
+
// Already emitted.
if (!GV->isDeclaration())
return;
diff --git a/clang/test/CodeGen/unique-internal-linkage-names-alias.c
b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
new file mode 100644
index 0..14bfea08367d3
--- /dev/null
+++ b/clang/test/CodeGen/unique-internal-linkage-names-alias.c
@@ -0,0 +1,10 @@
+
[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
https://github.com/HighW4y2H3ll created
https://github.com/llvm/llvm-project/pull/145652
`-funique-internal-linkage-names` mangles function symbols even for C
functions. When using `__attribute__((alias()))`, it's a bit counter-intuitive
to specify a C++ mangled symbol name in the attribute. Besides, `EmitGlobal`
won't be able to emit the *aliasee* function because its name has been changed
which no longer matches any GlobalValue name in the emitted LLVM Module. This
patch fixes the `EmitGlobal` function which emits a function with the mangled
name, and resolves the C symbol inside `__attribute__((alias))` to its uniquely
mangled name to keep the behavior consistent.
>From 9a29dd6fa3f28bf507f047a22597f8510bd096b3 Mon Sep 17 00:00:00 2001
From: h2h
Date: Tue, 24 Jun 2025 23:24:32 -0700
Subject: [PATCH] [Clang] Allow vanilla C function symbol name to be used in
__attribute__((alias)) when -funique-internal-linkage-names is specified
---
clang/lib/CodeGen/CodeGenModule.cpp | 48 +--
.../unique-internal-linkage-names-alias.c | 10
2 files changed, 54 insertions(+), 4 deletions(-)
create mode 100644 clang/test/CodeGen/unique-internal-linkage-names-alias.c
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+
[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
efriedma-quic wrote:
I'm not really happy with this. The code for deferred declarations and
diagnosing name conflicts is complicated enough without adding the possibility
that the name of a declaration can change later.
Can we just suppress mangling in cases where we reference a symbol without
knowing if it's internal, then it turns out to be internal later?
https://github.com/llvm/llvm-project/pull/145652
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[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
efriedma-quic wrote:
Is this C-only? Consider something like:
```
long bar(const struct A*p) __attribute__((__alias__("foo")));
namespace {
extern "C" long foo(const struct A*p) {return 1;}
}
```
https://github.com/llvm/llvm-project/pull/145652
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[clang] [Clang] Allow vanilla C function symbol name to be used in __attribute__((alias)) when -funique-internal-linkage-names is specified (PR #145652)
llvmbot wrote:
@llvm/pr-subscribers-clang
@llvm/pr-subscribers-clang-codegen
Author: None (HighW4y2H3ll)
Changes
`-funique-internal-linkage-names` mangles function symbols even for C
functions. When using `__attribute__((alias()))`, it's a bit counter-intuitive
to specify a C++ mangled symbol name in the attribute. Besides, `EmitGlobal`
won't be able to emit the *aliasee* function because its name has been changed
which no longer matches any GlobalValue name in the emitted LLVM Module. This
patch fixes the `EmitGlobal` function which emits a function with the mangled
name, and resolves the C symbol inside `__attribute__((alias))` to its uniquely
mangled name to keep the behavior consistent.
---
Full diff: https://github.com/llvm/llvm-project/pull/145652.diff
2 Files Affected:
- (modified) clang/lib/CodeGen/CodeGenModule.cpp (+44-4)
- (added) clang/test/CodeGen/unique-internal-linkage-names-alias.c (+10)
``diff
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 16688810d0685..90f02220ec306 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -588,8 +588,9 @@ static const llvm::GlobalValue *getAliasedGlobal(const
llvm::GlobalValue *GV) {
}
static bool checkAliasedGlobal(
-const ASTContext &Context, DiagnosticsEngine &Diags, SourceLocation
Location,
-bool IsIFunc, const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
+const CodeGenModule *CGM, const ASTContext &Context,
+DiagnosticsEngine &Diags, SourceLocation Location, bool IsIFunc,
+const llvm::GlobalValue *Alias, const llvm::GlobalValue *&GV,
const llvm::MapVector &MangledDeclNames,
SourceRange AliasRange) {
GV = getAliasedGlobal(Alias);
@@ -598,6 +599,23 @@ static bool checkAliasedGlobal(
return false;
}
+ // Only resolve unique internal linkage symbols for C code
+ if (!CGM->getLangOpts().CPlusPlus) {
+for (const auto &[Decl, Name] : MangledDeclNames) {
+ if (const auto *ND = dyn_cast(Decl.getDecl())) {
+IdentifierInfo *II = ND->getIdentifier();
+if (II && II->getName() == GV->getName() &&
+Name.contains(llvm::FunctionSamples::UniqSuffix)) {
+ GlobalDecl GD;
+ if (CGM->lookupRepresentativeDecl(Name, GD)) {
+GV = CGM->getModule().getNamedValue(Name);
+break;
+ }
+}
+ }
+}
+ }
+
if (GV->hasCommonLinkage()) {
const llvm::Triple &Triple = Context.getTargetInfo().getTriple();
if (Triple.getObjectFormat() == llvm::Triple::XCOFF) {
@@ -687,8 +705,8 @@ void CodeGenModule::checkAliases() {
StringRef MangledName = getMangledName(GD);
llvm::GlobalValue *Alias = GetGlobalValue(MangledName);
const llvm::GlobalValue *GV = nullptr;
-if (!checkAliasedGlobal(getContext(), Diags, Location, IsIFunc, Alias, GV,
-MangledDeclNames, Range)) {
+if (!checkAliasedGlobal(this, getContext(), Diags, Location, IsIFunc,
Alias,
+GV, MangledDeclNames, Range)) {
Error = true;
continue;
}
@@ -4038,6 +4056,7 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
CXXGlobalInits.push_back(nullptr);
}
+ const auto *ND = dyn_cast(GD.getDecl());
StringRef MangledName = getMangledName(GD);
if (GetGlobalValue(MangledName) != nullptr) {
// The value has already been used and should therefore be emitted.
@@ -4046,6 +4065,12 @@ void CodeGenModule::EmitGlobal(GlobalDecl GD) {
// The value must be emitted, but cannot be emitted eagerly.
assert(!MayBeEmittedEagerly(Global));
addDeferredDeclToEmit(GD);
+ } else if (!getLangOpts().CPlusPlus && ND &&
+ GetGlobalValue(ND->getName()) != nullptr &&
+ MangledName.contains(llvm::FunctionSamples::UniqSuffix)) {
+// Emit static C function that is mangled with
+// -funique-internal-linkage-names.
+addDeferredDeclToEmit(GD);
} else {
// Otherwise, remember that we saw a deferred decl with this name. The
// first use of the mangled name will cause it to move into
@@ -6189,6 +6214,21 @@ void
CodeGenModule::EmitGlobalFunctionDefinition(GlobalDecl GD,
/*DontDefer=*/true,
ForDefinition));
+ if (!getLangOpts().CPlusPlus &&
+ getCXXABI().getMangleContext().shouldMangleDeclName(D)) {
+// -funique-internal-linkage-names may change the symbol name of C
function.
+// Replace all uses of old symbol with the emitted global value.
+if (IdentifierInfo *II = D->getIdentifier()) {
+ if (II->getName() != GV->getName() &&
+ GV->getName().contains(llvm::FunctionSamples::UniqSuffix)) {
+if (llvm::GlobalValue *GVDef =
+getModule().getNamedValue(D->getName())) {
+ GVDef->replaceAllUsesWith(GV);
+}
+ }
+}
+ }
+
// Already emitte
