https://github.com/erichkeane updated https://github.com/llvm/llvm-project/pull/212308
>From 33c666fb7a93dc18c9f42b6d0204090e8bf4cff6 Mon Sep 17 00:00:00 2001 From: erichkeane <[email protected]> Date: Fri, 24 Jul 2026 16:45:21 -0700 Subject: [PATCH 1/2] [CIR] Fixup type of no-prototype functions when emitting an alias. If a function is first used through a no-prototype declaration, then defined later as an alias, we erased the old declaration and created the new one with the new type. However the earlier references still used the old type, which caused a verification error. This patch just makes sure we replace the uses of it similar to how we do with a similar problem with normal functions. Note: there is a bit of inconsistency in how we're setting the type of the function between OGCG and CIR that I'm not sure of the impact of, but that is prexisting. --- clang/lib/CIR/CodeGen/CIRGenModule.cpp | 39 ++++++++++++------- clang/test/CIR/CodeGen/attr-alias.c | 54 +++++++++++++++++++++++++- 2 files changed, 77 insertions(+), 16 deletions(-) diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.cpp b/clang/lib/CIR/CodeGen/CIRGenModule.cpp index 8b9140caa7471..209671ad47be5 100644 --- a/clang/lib/CIR/CodeGen/CIRGenModule.cpp +++ b/clang/lib/CIR/CodeGen/CIRGenModule.cpp @@ -2036,6 +2036,10 @@ void CIRGenModule::replaceUsesOfNonProtoTypeWithRealFunction( // Iterate through all calls of the no-proto function. std::optional<mlir::SymbolTable::UseRange> symUses = oldFn.getSymbolUses(oldFn->getParentOp()); + + if (!symUses) + return; + for (const mlir::SymbolTable::SymbolUse &use : symUses.value()) { mlir::OpBuilder::InsertionGuard guard(builder); @@ -3768,34 +3772,41 @@ void CIRGenModule::emitAliasDefinition(GlobalDecl gd) { const auto *vd = cast<VarDecl>(d); linkage = getCIRLinkageVarDefinition(vd); } - - // Aliases that target weak symbols must themselves be marked weak. - if (d->hasAttr<WeakAttr>() || d->hasAttr<WeakRefAttr>() || - d->isWeakImported()) - linkage = cir::GlobalLinkageKind::WeakAnyLinkage; + // + // Create the alias op. + // TODO(cir): Make GlobalAlias a separate op. + cir::CIRGlobalValueInterface alias = + isFunction ? mlir::cast<cir::CIRGlobalValueInterface>( + createCIRFunction(loc, mangledName, + mlir::cast<cir::FuncType>(declTy), + cast<FunctionDecl>(d)) + .getOperation()) + : mlir::cast<cir::CIRGlobalValueInterface>( + createGlobalOp(loc, mangledName, declTy).getOperation()); // Create the alias op. If there is an existing declaration with the same // name, erase it: any references to it via flat symbol reference will // automatically resolve to the new alias. + // However, function aliases actually change its type, so we have to replace + // uses of it. if (entry) { + if (isFunction) + replaceUsesOfNonProtoTypeWithRealFunction( + entry, mlir::cast<cir::FuncOp>(alias.getOperation())); eraseGlobalSymbol(entry); entry->erase(); } + // Aliases that target weak symbols must themselves be marked weak. + if (d->hasAttr<WeakAttr>() || d->hasAttr<WeakRefAttr>() || + d->isWeakImported()) + linkage = cir::GlobalLinkageKind::WeakAnyLinkage; + // Aliases are always definitions, so the MLIR visibility should match the // linkage rather than defaulting to private. mlir::SymbolTable::Visibility visibility = getMLIRVisibilityFromCIRLinkage(linkage); - // TODO(cir): Make GlobalAlias a separate op. - cir::CIRGlobalValueInterface alias = - isFunction ? mlir::cast<cir::CIRGlobalValueInterface>( - createCIRFunction(loc, mangledName, - mlir::cast<cir::FuncType>(declTy), - cast<FunctionDecl>(d)) - .getOperation()) - : mlir::cast<cir::CIRGlobalValueInterface>( - createGlobalOp(loc, mangledName, declTy).getOperation()); alias.setAliasee(aa->getAliasee()); alias.setLinkage(linkage); mlir::SymbolTable::setSymbolVisibility(alias, visibility); diff --git a/clang/test/CIR/CodeGen/attr-alias.c b/clang/test/CIR/CodeGen/attr-alias.c index 3acf90d6a4d22..d7bd525d9b974 100644 --- a/clang/test/CIR/CodeGen/attr-alias.c +++ b/clang/test/CIR/CodeGen/attr-alias.c @@ -26,6 +26,24 @@ extern void prior_decl_func(void); void prior_decl_func_target(void) {} extern void prior_decl_func(void) __attribute__((alias("prior_decl_func_target"))); +// Use of a no-prototype function, then alias definition sets the type. +extern int noproto_used(); +int noproto_use_it(void) { return noproto_used(); } +int noproto_used_target(void) { return 0; } +int noproto_used() __attribute__((alias("noproto_used_target"))); + +// Use of a no-prototype function with args, then alias definition sets the type. +extern int noproto_args(); +int noproto_args_use(void) { return noproto_args(1, 2, 3); } +int noproto_args_target(void) { return 0; } +int noproto_args() __attribute__((alias("noproto_args_target"))); + +// Use of a no-prototype function with args, alias adds args. +extern int noproto_args2(); +int noproto_args_use2(void) { return noproto_args2(1, 2, 3); } +int noproto_args_target2(void) { return 0; } +int noproto_args2(int, int, int) __attribute__((alias("noproto_args_target2"))); + // Weak variable alias - exercises the WeakAttr linkage override branch. int weak_var_target = 9; extern int weak_var_alias __attribute__((weak, alias("weak_var_target"))); @@ -49,6 +67,18 @@ extern void weak_func_alias(void) __attribute__((weak, alias("weak_func_target") // CIR-DAG: cir.func weak @weak_func_alias() alias(@weak_func_target) // CIR-DAG: cir.func dso_local @test13_alias(!u32i) alias(@test13) +// CIR-DAG: cir.get_global @noproto_used : !cir.ptr<!cir.func<() -> !s32i>> +// CIR-DAG: cir.func no_proto dso_local @noproto_used() -> !s32i alias(@noproto_used_target) +// CIR-DAG: cir.call {{.*}}() : (!cir.ptr<!cir.func<() -> !s32i>>) -> !s32i + +// CIR-DAG: cir.get_global @noproto_args : !cir.ptr<!cir.func<() -> !s32i>> +// CIR-DAG: cir.call {{%.*}}({{.*}}) : (!cir.ptr<!cir.func<(!s32i, !s32i, !s32i) -> !s32i>>{{.*}}) -> !s32i +// CIR-DAG: cir.func no_proto dso_local @noproto_args() -> !s32i alias(@noproto_args_target) + +// CIR-DAG: cir.get_global @noproto_args2 : !cir.ptr<!cir.func<(!s32i, !s32i, !s32i) -> !s32i>> +// CIR-DAG: cir.call {{%.*}}({{.*}}) : (!cir.ptr<!cir.func<(!s32i, !s32i, !s32i) -> !s32i>>{{.*}}) -> !s32i +// CIR-DAG: cir.func no_proto dso_local @noproto_args2(!s32i, !s32i, !s32i) -> !s32i alias(@noproto_args_target2) + // LLVM-DAG: @alias_target = global i32 42 // LLVM-DAG: @prior_decl_var_target = global i32 7 // LLVM-DAG: @weak_var_target = global i32 9 @@ -59,7 +89,17 @@ extern void weak_func_alias(void) __attribute__((weak, alias("weak_func_target") // LLVM-DAG: @prior_decl_func = alias void (), ptr @prior_decl_func_target // LLVM-DAG: @weak_func_alias = weak alias void (), ptr @weak_func_target // LLVM-DAG: @test13_alias = alias void (i32), ptr @test13 -// LLVM: define {{.*}}void @alias_func_target() + +// LLVM-DAG: @noproto_used = alias i32 (), ptr @noproto_used_target +// LLVM-DAG: call i32 @noproto_used() +// +// LLVM-DAG: @noproto_args = alias i32 (), ptr @noproto_args_target +// LLVM-DAG: call i32 @noproto_args(i32 noundef 1, i32 noundef 2, i32 noundef 3) +// +// LLVM-DAG: call i32 @noproto_args2(i32 noundef 1, i32 noundef 2, i32 noundef 3) +// LLVM-DAG: @noproto_args2 = alias i32 (i32, i32, i32), ptr @noproto_args_target2 + +// LLVM-DAG: define {{.*}}void @alias_func_target() // OGCG-DAG: @alias_target = {{.*}}global i32 42 // OGCG-DAG: @prior_decl_var_target = {{.*}}global i32 7 @@ -71,7 +111,17 @@ extern void weak_func_alias(void) __attribute__((weak, alias("weak_func_target") // OGCG-DAG: @prior_decl_func = {{.*}}alias void (), ptr @prior_decl_func_target // OGCG-DAG: @weak_func_alias = {{.*}}weak alias void (), ptr @weak_func_target // OGCG-DAG: @test13_alias = alias {}, ptr @test13 -// OGCG: define {{.*}}void @alias_func_target() +// +// OGCG-DAG: @noproto_used = alias i32 (...), ptr @noproto_used_target +// OGCG-DAG: call i32 (...) @noproto_used() +// +// OGCG-DAG: @noproto_args = alias i32 (...), ptr @noproto_args_target +// OGCG-DAG: call i32 (i32, i32, i32, ...) @noproto_args(i32 noundef 1, i32 noundef 2, i32 noundef 3) +// +// OGCG-DAG: call i32 (i32, i32, i32, ...) @noproto_args2(i32 noundef 1, i32 noundef 2, i32 noundef 3) +// OGCG-DAG: @noproto_args2 = alias i32 (i32, i32, i32), ptr @noproto_args_target2 +// +// OGCG-DAG: define {{.*}}void @alias_func_target() // Test that a non visible (-Wvisibility) type doesn't assert. enum a_type { test13_a }; >From 32f43cea3736358f9e20811544968c19b96b6da8 Mon Sep 17 00:00:00 2001 From: erichkeane <[email protected]> Date: Thu, 30 Jul 2026 06:07:21 -0700 Subject: [PATCH 2/2] Split off test to make it more clear what is happening here. Note; There is a bug somewhere in lowering of variadic functions, so that was filed as an issue. --- clang/test/CIR/CodeGen/attr-alias-no-proto.c | 88 ++++++++++++++++++++ clang/test/CIR/CodeGen/attr-alias.c | 54 +----------- 2 files changed, 90 insertions(+), 52 deletions(-) create mode 100644 clang/test/CIR/CodeGen/attr-alias-no-proto.c diff --git a/clang/test/CIR/CodeGen/attr-alias-no-proto.c b/clang/test/CIR/CodeGen/attr-alias-no-proto.c new file mode 100644 index 0000000000000..c6e61bdca668a --- /dev/null +++ b/clang/test/CIR/CodeGen/attr-alias-no-proto.c @@ -0,0 +1,88 @@ +// RUN: %clang_cc1 -std=c11 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir +// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s +// RUN: %clang_cc1 -std=c11 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o %t-cir.ll +// RUN: FileCheck --check-prefix=LLVM --input-file=%t-cir.ll %s +// RUN: %clang_cc1 -std=c11 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o %t.ll +// RUN: FileCheck --check-prefix=OGCG --input-file=%t.ll %s + +// LLVM: @noproto_used = alias i32 (), ptr @noproto_used_target +// LLVM: @noproto_args = alias i32 (), ptr @noproto_args_target +// LLVM: @noproto_args2 = alias i32 (i32, i32, i32), ptr @noproto_args_target2 + +// FIXME(cir): we list no-proto for the alias in CIR, but perhaps lowering is +// missing it? We should be able to combine LLVM/OGCG check lines in this file. +// Filed: https://github.com/llvm/llvm-project/issues/213024 +// +// OGCG: @noproto_used = alias i32 (...), ptr @noproto_used_target +// OGCG: @noproto_args = alias i32 (...), ptr @noproto_args_target +// OGCG: @noproto_args2 = alias i32 (i32, i32, i32), ptr @noproto_args_target2 + +// Use of a no-prototype function, then alias definition sets the type. +extern int noproto_used(); +int noproto_use_it(void) { return noproto_used(); } +int noproto_used_target(void) { return 0; } +int noproto_used() __attribute__((alias("noproto_used_target"))); + +// Note: Function attrs no_inline/dso_local included to show that no_proto is +// NOT present. +// CIR-LABEL: cir.func no_inline dso_local @noproto_use_it() -> !s32i +// CIR: %[[GET_USED:.*]] = cir.get_global @noproto_used : !cir.ptr<!cir.func<() -> !s32i>> +// CIR: cir.call %[[GET_USED]]() : (!cir.ptr<!cir.func<() -> !s32i>>) -> !s32i + +// LLVM-LABEL: define dso_local i32 @noproto_use_it() +// LLVM: call i32 @noproto_used() +// OGCG: define dso_local i32 @noproto_use_it() +// OGCG: call i32 (...) @noproto_used() + +// CIR-LABEL: cir.func no_inline dso_local @noproto_used_target() -> !s32i +// LLVM-LABEL: define dso_local i32 @noproto_used_target() +// OGCG-LABEL: define dso_local i32 @noproto_used_target() + +// CIR: cir.func no_proto dso_local @noproto_used() -> !s32i alias(@noproto_used_target) +// LLVM sorts these at the top of the file. + +// Use of a no-prototype function with args, then alias definition sets the type. +extern int noproto_args(); +int noproto_args_use(void) { return noproto_args(1, 2, 3); } +int noproto_args_target(void) { return 0; } +int noproto_args() __attribute__((alias("noproto_args_target"))); +// CIR-LABEL: cir.func no_inline dso_local @noproto_args_use() -> !s32i +// CIR: %[[GET_NPA:.*]] = cir.get_global @noproto_args : !cir.ptr<!cir.func<() -> !s32i>> +// CIR: %[[TO_VARIADIC:.*]] = cir.cast bitcast %[[GET_NPA]] : !cir.ptr<!cir.func<() -> !s32i>> -> !cir.ptr<!cir.func<(...) -> !s32i>> +// CIR: %[[TO_TYPED:.*]] = cir.cast bitcast %[[TO_VARIADIC]] : !cir.ptr<!cir.func<(...) -> !s32i>> -> !cir.ptr<!cir.func<(!s32i, !s32i, !s32i) -> !s32i>> +// CIR: cir.call %[[TO_TYPED]](%{{.*}}, %{{.*}}, %{{.*}}) : (!cir.ptr<!cir.func<(!s32i, !s32i, !s32i) -> !s32i>>, !s32i {llvm.noundef}, !s32i {llvm.noundef}, !s32i {llvm.noundef}) -> !s32i +// +// LLVM-LABEL: define dso_local i32 @noproto_args_use() +// LLVM: call i32 @noproto_args(i32 noundef 1, i32 noundef 2, i32 noundef 3) +// OGCG-LABEL: define dso_local i32 @noproto_args_use() +// OGCG: call i32 (i32, i32, i32, ...) @noproto_args(i32 noundef 1, i32 noundef 2, i32 noundef 3) + +// CIR-LABEL: cir.func no_inline dso_local @noproto_args_target() -> !s32i +// LLVM-LABEL: define dso_local i32 @noproto_args_target() +// OGCG-LABEL: define dso_local i32 @noproto_args_target() + +// CIR: cir.func no_proto dso_local @noproto_args() -> !s32i alias(@noproto_args_target) +// LLVM sorts these at the top of the file. + +// Use of a no-prototype function with args, alias adds args, type fixed before +// use, so casts unnecessary. +extern int noproto_args2(); +int noproto_args_use2(void) { return noproto_args2(1, 2, 3); } +int noproto_args_target2(void) { return 0; } +int noproto_args2(int, int, int) __attribute__((alias("noproto_args_target2"))); + +// CIR-LABEL: cir.func no_inline dso_local @noproto_args_use2() -> !s32i +// CIR: %[[GET_NPA:.*]] = cir.get_global @noproto_args2 : !cir.ptr<!cir.func<(!s32i, !s32i, !s32i) -> !s32i>> +// CIR: cir.call %4(%{{.*}}, %{{.*}}, %{{.*}}) : (!cir.ptr<!cir.func<(!s32i, !s32i, !s32i) -> !s32i>>, !s32i {llvm.noundef}, !s32i {llvm.noundef}, !s32i {llvm.noundef}) -> !s32i +// +// LLVM-LABEL: define dso_local i32 @noproto_args_use2() +// LLVM: call i32 @noproto_args2(i32 noundef 1, i32 noundef 2, i32 noundef 3) +// OGCG-LABEL: define dso_local i32 @noproto_args_use2() +// OGCG: call i32 (i32, i32, i32, ...) @noproto_args2(i32 noundef 1, i32 noundef 2, i32 noundef 3) + +// CIR-LABEL: cir.func no_inline dso_local @noproto_args_target2() -> !s32i +// LLVM-LABEL: define dso_local i32 @noproto_args_target2() +// OGCG-LABEL: define dso_local i32 @noproto_args_target2() + +// CIR: cir.func no_proto dso_local @noproto_args2(!s32i, !s32i, !s32i) -> !s32i alias(@noproto_args_target2) +// LLVM sorts these at the top of the file. diff --git a/clang/test/CIR/CodeGen/attr-alias.c b/clang/test/CIR/CodeGen/attr-alias.c index d7bd525d9b974..3acf90d6a4d22 100644 --- a/clang/test/CIR/CodeGen/attr-alias.c +++ b/clang/test/CIR/CodeGen/attr-alias.c @@ -26,24 +26,6 @@ extern void prior_decl_func(void); void prior_decl_func_target(void) {} extern void prior_decl_func(void) __attribute__((alias("prior_decl_func_target"))); -// Use of a no-prototype function, then alias definition sets the type. -extern int noproto_used(); -int noproto_use_it(void) { return noproto_used(); } -int noproto_used_target(void) { return 0; } -int noproto_used() __attribute__((alias("noproto_used_target"))); - -// Use of a no-prototype function with args, then alias definition sets the type. -extern int noproto_args(); -int noproto_args_use(void) { return noproto_args(1, 2, 3); } -int noproto_args_target(void) { return 0; } -int noproto_args() __attribute__((alias("noproto_args_target"))); - -// Use of a no-prototype function with args, alias adds args. -extern int noproto_args2(); -int noproto_args_use2(void) { return noproto_args2(1, 2, 3); } -int noproto_args_target2(void) { return 0; } -int noproto_args2(int, int, int) __attribute__((alias("noproto_args_target2"))); - // Weak variable alias - exercises the WeakAttr linkage override branch. int weak_var_target = 9; extern int weak_var_alias __attribute__((weak, alias("weak_var_target"))); @@ -67,18 +49,6 @@ extern void weak_func_alias(void) __attribute__((weak, alias("weak_func_target") // CIR-DAG: cir.func weak @weak_func_alias() alias(@weak_func_target) // CIR-DAG: cir.func dso_local @test13_alias(!u32i) alias(@test13) -// CIR-DAG: cir.get_global @noproto_used : !cir.ptr<!cir.func<() -> !s32i>> -// CIR-DAG: cir.func no_proto dso_local @noproto_used() -> !s32i alias(@noproto_used_target) -// CIR-DAG: cir.call {{.*}}() : (!cir.ptr<!cir.func<() -> !s32i>>) -> !s32i - -// CIR-DAG: cir.get_global @noproto_args : !cir.ptr<!cir.func<() -> !s32i>> -// CIR-DAG: cir.call {{%.*}}({{.*}}) : (!cir.ptr<!cir.func<(!s32i, !s32i, !s32i) -> !s32i>>{{.*}}) -> !s32i -// CIR-DAG: cir.func no_proto dso_local @noproto_args() -> !s32i alias(@noproto_args_target) - -// CIR-DAG: cir.get_global @noproto_args2 : !cir.ptr<!cir.func<(!s32i, !s32i, !s32i) -> !s32i>> -// CIR-DAG: cir.call {{%.*}}({{.*}}) : (!cir.ptr<!cir.func<(!s32i, !s32i, !s32i) -> !s32i>>{{.*}}) -> !s32i -// CIR-DAG: cir.func no_proto dso_local @noproto_args2(!s32i, !s32i, !s32i) -> !s32i alias(@noproto_args_target2) - // LLVM-DAG: @alias_target = global i32 42 // LLVM-DAG: @prior_decl_var_target = global i32 7 // LLVM-DAG: @weak_var_target = global i32 9 @@ -89,17 +59,7 @@ extern void weak_func_alias(void) __attribute__((weak, alias("weak_func_target") // LLVM-DAG: @prior_decl_func = alias void (), ptr @prior_decl_func_target // LLVM-DAG: @weak_func_alias = weak alias void (), ptr @weak_func_target // LLVM-DAG: @test13_alias = alias void (i32), ptr @test13 - -// LLVM-DAG: @noproto_used = alias i32 (), ptr @noproto_used_target -// LLVM-DAG: call i32 @noproto_used() -// -// LLVM-DAG: @noproto_args = alias i32 (), ptr @noproto_args_target -// LLVM-DAG: call i32 @noproto_args(i32 noundef 1, i32 noundef 2, i32 noundef 3) -// -// LLVM-DAG: call i32 @noproto_args2(i32 noundef 1, i32 noundef 2, i32 noundef 3) -// LLVM-DAG: @noproto_args2 = alias i32 (i32, i32, i32), ptr @noproto_args_target2 - -// LLVM-DAG: define {{.*}}void @alias_func_target() +// LLVM: define {{.*}}void @alias_func_target() // OGCG-DAG: @alias_target = {{.*}}global i32 42 // OGCG-DAG: @prior_decl_var_target = {{.*}}global i32 7 @@ -111,17 +71,7 @@ extern void weak_func_alias(void) __attribute__((weak, alias("weak_func_target") // OGCG-DAG: @prior_decl_func = {{.*}}alias void (), ptr @prior_decl_func_target // OGCG-DAG: @weak_func_alias = {{.*}}weak alias void (), ptr @weak_func_target // OGCG-DAG: @test13_alias = alias {}, ptr @test13 -// -// OGCG-DAG: @noproto_used = alias i32 (...), ptr @noproto_used_target -// OGCG-DAG: call i32 (...) @noproto_used() -// -// OGCG-DAG: @noproto_args = alias i32 (...), ptr @noproto_args_target -// OGCG-DAG: call i32 (i32, i32, i32, ...) @noproto_args(i32 noundef 1, i32 noundef 2, i32 noundef 3) -// -// OGCG-DAG: call i32 (i32, i32, i32, ...) @noproto_args2(i32 noundef 1, i32 noundef 2, i32 noundef 3) -// OGCG-DAG: @noproto_args2 = alias i32 (i32, i32, i32), ptr @noproto_args_target2 -// -// OGCG-DAG: define {{.*}}void @alias_func_target() +// OGCG: define {{.*}}void @alias_func_target() // Test that a non visible (-Wvisibility) type doesn't assert. enum a_type { test13_a }; 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