Author: Sam Elliott Date: 2026-02-18T10:16:31-08:00 New Revision: df1eec77b55603f9e63840dfdada03c6d4d5b5e6
URL: https://github.com/llvm/llvm-project/commit/df1eec77b55603f9e63840dfdada03c6d4d5b5e6 DIFF: https://github.com/llvm/llvm-project/commit/df1eec77b55603f9e63840dfdada03c6d4d5b5e6.diff LOG: [clang] Ensure -mno-outline adds attributes (#163692) Before this change, `-mno-outline` and `-moutline` only controlled the pass pipelines for the invoked compiler/linker. The drawback of this implementation is that, when using LTO, only the flag provided to the linker invocation is honoured (and any files which individually use `-mno-outline` will have that flag ignored). This change serialises the `-mno-outline` flag into each function's IR/Bitcode, so that we can correctly disable outlining from functions in files which disabled outlining, without affecting outlining choices for functions from other files. This matches how other optimisation flags are handled so the IR/Bitcode can be correctly merged during LTO. Added: Modified: clang/docs/ReleaseNotes.rst clang/include/clang/Basic/CodeGenOptions.def clang/include/clang/Options/Options.td clang/lib/CodeGen/CodeGenModule.cpp clang/lib/Driver/ToolChains/CommonArgs.cpp clang/test/CodeGen/attr-no-outline.c clang/test/CodeGenObjC/attr-no-outline.m clang/test/Driver/aarch64-outliner.c clang/test/Driver/arm-machine-outliner.c clang/test/Driver/riscv-outliner.c clang/test/Driver/x86-outliner.c Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 86cee7d1b6f9b..56c8b79e37576 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -160,6 +160,8 @@ Deprecated Compiler Flags Modified Compiler Flags ----------------------- - The `-mno-outline` and `-moutline` compiler flags are now allowed on RISC-V and X86, which both support the machine outliner. +- The `-mno-outline` flag will now add the `nooutline` IR attribute, so that + `-mno-outline` and `-moutline` objects can be mixed correctly during LTO. Removed Compiler Flags ---------------------- diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def index 8c056bb690690..5e174b21be466 100644 --- a/clang/include/clang/Basic/CodeGenOptions.def +++ b/clang/include/clang/Basic/CodeGenOptions.def @@ -509,6 +509,9 @@ CODEGENOPT(AllResourcesBound, 1, 0, Benign) ENUM_CODEGENOPT(WinX64EHUnwindV2, WinX64EHUnwindV2Mode, 2, WinX64EHUnwindV2Mode::Disabled, Benign) +/// Adds attributes that prevent outlining (`-mno-outline`) +CODEGENOPT(DisableOutlining, 1, 0, Benign) + /// FIXME: Make DebugOptions its own top-level .def file. #include "DebugOptions.def" diff --git a/clang/include/clang/Options/Options.td b/clang/include/clang/Options/Options.td index 24b31fb3fefcc..c8fb2a55fe7ac 100644 --- a/clang/include/clang/Options/Options.td +++ b/clang/include/clang/Options/Options.td @@ -5300,16 +5300,13 @@ def mmacos_version_min_EQ : Joined<["-"], "mmacos-version-min=">, def : Joined<["-"], "mmacosx-version-min=">, Visibility<[ClangOption, CC1Option, FC1Option, FlangOption]>, Group<m_Group>, Alias<mmacos_version_min_EQ>; -def moutline - : Flag<["-"], "moutline">, - Group<f_clang_Group>, - Visibility<[ClangOption, CC1Option]>, - HelpText<"Enable function outlining (AArch64,Arm,RISC-V,X86 only)">; -def mno_outline - : Flag<["-"], "mno-outline">, - Group<f_clang_Group>, - Visibility<[ClangOption, CC1Option]>, - HelpText<"Disable function outlining (AArch64,Arm,RISC-V,X86 only)">; +defm outline + : BoolMOption< + "outline", CodeGenOpts<"DisableOutlining">, DefaultFalse, + NegFlag<SetTrue, [], [ClangOption, CC1Option], + "Disable function outlining (AArch64,Arm,RISC-V,X86 only)">, + PosFlag<SetFalse, [], [ClangOption], + "Enable function outlining (AArch64,Arm,RISC-V,X86 only)">>; def mms_bitfields : Flag<["-"], "mms-bitfields">, Group<m_Group>, HelpText<"Set the default structure layout to be compatible with the Microsoft compiler standard">; def mno_ms_bitfields : Flag<["-"], "mno-ms-bitfields">, Group<m_Group>, diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp index 6a087be3751f0..43b8af0b2156a 100644 --- a/clang/lib/CodeGen/CodeGenModule.cpp +++ b/clang/lib/CodeGen/CodeGenModule.cpp @@ -2928,7 +2928,9 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D, B.addAttribute(llvm::Attribute::MinSize); } - if (D->hasAttr<NoOutlineAttr>()) + // Add `nooutline` if Outlining is disabled with a command-line flag or a + // function attribute. + if (CodeGenOpts.DisableOutlining || D->hasAttr<NoOutlineAttr>()) B.addAttribute(llvm::Attribute::NoOutline); F->addFnAttrs(B); diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp index 8bb271d27a3c4..9a17fa2546e68 100644 --- a/clang/lib/Driver/ToolChains/CommonArgs.cpp +++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp @@ -2966,11 +2966,12 @@ void tools::addMachineOutlinerArgs(const Driver &D, D.Diag(diag::warn_drv_moutline_unsupported_opt) << Triple.getArchName(); } } else { - // Disable all outlining behaviour. - // - // FIXME: This should probably use the `nooutline` attribute rather than - // tweaking Pipeline Pass flags, so `-mno-outline` and `-moutline` objects - // can be combined correctly during LTO. + if (!IsLTO) + // Disable all outlining behaviour using `nooutline` attribute, in case + // Linker Invocation lacks `-mno-outline`. + CmdArgs.push_back("-mno-outline"); + + // Disable Pass in Pipeline addArg(Twine("-enable-machine-outliner=never")); } } diff --git a/clang/test/CodeGen/attr-no-outline.c b/clang/test/CodeGen/attr-no-outline.c index 60d2ab5563f34..3e82ca338a121 100644 --- a/clang/test/CodeGen/attr-no-outline.c +++ b/clang/test/CodeGen/attr-no-outline.c @@ -1,16 +1,46 @@ -// RUN: %clang_cc1 -emit-llvm -x c %s -triple x86_64-unknown-linux-gnu -o - -femit-all-decls -fblocks | FileCheck %s --check-prefix=C -// RUN: %clang_cc1 -emit-llvm -x c++ %s -triple x86_64-unknown-linux-gnu -o - -femit-all-decls -fblocks | FileCheck %s --check-prefix=CXX -// RUN: %clang_cc1 -emit-llvm -x c++ %s -triple x86_64-unknown-linux-gnu -o - -femit-all-decls -fblocks -std=c++23 | FileCheck %s --check-prefixes=CXX,CXX23 +// RUN: %clang_cc1 -emit-llvm -x c %s -triple x86_64-unknown-linux-gnu -o - -femit-all-decls -fblocks -DTEST_ATTR | FileCheck %s --check-prefix=C,C-ATTR +// RUN: %clang_cc1 -emit-llvm -x c %s -triple x86_64-unknown-linux-gnu -o - -femit-all-decls -fblocks -mno-outline | FileCheck %s --check-prefix=C,C-ARG +// RUN: %clang_cc1 -emit-llvm -x c %s -triple x86_64-unknown-linux-gnu -o - -femit-all-decls -fblocks | FileCheck %s --check-prefix=C,C-NONE + + +// RUN: %clang_cc1 -emit-llvm -x c++ %s -triple x86_64-unknown-linux-gnu -o - -femit-all-decls -fblocks -std=c++23 -DTEST_ATTR | FileCheck %s --check-prefixes=CXX,CXX-ATTR +// RUN: %clang_cc1 -emit-llvm -x c++ %s -triple x86_64-unknown-linux-gnu -o - -femit-all-decls -fblocks -std=c++23 -mno-outline | FileCheck %s --check-prefixes=CXX,CXX-ARG +// RUN: %clang_cc1 -emit-llvm -x c++ %s -triple x86_64-unknown-linux-gnu -o - -femit-all-decls -fblocks -std=c++23 | FileCheck %s --check-prefixes=CXX,CXX-NONE + +// This test checks that: +// - [[clang::no_outline]] adds the nooutline IR attribute to specific definitions +// - `-mno-outline` adds the nooutline IR attribute to all definitions +// - Lack of either does not add nooutline IR attribute + +#ifdef TEST_ATTR +#define ATTR [[clang::no_outline]] +#define ATTR_DUNDER __attribute__((no_outline)) +#else +#define ATTR +#define ATTR_DUNDER +#endif // C-LABEL: define dso_local i32 @toplevel_func( -// C-SAME: ) #[[ATTR0:[0-9]+]] { +// C-SAME: ) #[[ATTR1:[0-9]+]] { // CXX-LABEL: define dso_local noundef i32 @_Z13toplevel_funci( -// CXX-SAME: ) #[[ATTR0:[0-9]+]] { -[[clang::no_outline]] int toplevel_func(int x) { +// CXX-SAME: ) #[[ATTR1:[0-9]+]] { +ATTR int toplevel_func(int x) { return x; } +// C-LABEL: define dso_local i32 @toplevel_func_noattr( +// C-ATTR-SAME: ) #[[ATTR2:[0-9]+]] { +// C-ARG-SAME: ) #[[ATTR1]] { +// C-NONE-SAME: ) #[[ATTR1]] { + +// CXX-LABEL: define dso_local noundef i32 @_Z20toplevel_func_noattri( +// CXX-ATTR-SAME: ) #[[ATTR2:[0-9]+]] { +// CXX-ARG-SAME: ) #[[ATTR1]] { +// CXX-NONE-SAME: ) #[[ATTR1]] { +int toplevel_func_noattr(int x) { + return x; +} // C-only: Function without prototype #ifndef __cplusplus @@ -19,9 +49,9 @@ #pragma clang diagnostic ignored "-Wimplicit-int" // C-LABEL: define dso_local i32 @no_proto_func( -// C-SAME: ) #[[ATTR0]] { +// C-SAME: ) #[[ATTR1]] { -[[clang::no_outline]] no_proto_func(x) +ATTR no_proto_func(x) int x; { return x; } @@ -32,14 +62,25 @@ int x; { // With Blocks #if __has_feature(blocks) +// C-LABEL: define dso_local i32 @func_with_block( +// C-ATTR-SAME: ) #[[ATTR2]] { +// C-ARG-SAME: ) #[[ATTR1]] { +// C-NONE-SAME: ) #[[ATTR1]] { + +// CXX-LABEL: define dso_local noundef i32 @_Z15func_with_blocki( +// CXX-ATTR-SAME: ) #[[ATTR2]] { +// CXX-ARG-SAME: ) #[[ATTR1]] { +// CXX-NONE-SAME: ) #[[ATTR1]] { int func_with_block(int x) { + // C-LABEL: define internal i32 @__func_with_block_block_invoke( -// C-SAME: ) #[[ATTR0]] { +// C-SAME: ) #[[ATTR1]] { // CXX-LABEL: define internal noundef i32 @___Z15func_with_blocki_block_invoke( -// CXX-SAME: ) #[[ATTR1:[0-9]+]] { - - int (^block)(int) = ^ __attribute__((no_outline)) int (int y) { return y; }; +// CXX-ATTR-SAME: ) #[[ATTR3:[0-9]+]] { +// CXX-ARG-SAME: ) #[[ATTR2:[0-9]+]] { +// CXX-NONE-SAME: ) #[[ATTR2:[0-9]+]] { + int (^block)(int) = ^ ATTR_DUNDER int (int y) { return y; }; return block(x); } @@ -51,57 +92,74 @@ int func_with_block(int x) { struct my_struct { // CXX-LABEL: define linkonce_odr noundef i32 @_ZN9my_struct11member_funcEi( -// CXX-SAME: ) #[[ATTR0]] comdat - [[clang::no_outline]] int member_func(int x) { +// CXX-SAME: ) #[[ATTR1]] comdat + ATTR int member_func(int x) { return x; } // CXX-LABEL: define linkonce_odr noundef i32 @_ZN9my_struct11static_funcEi( -// CXX-SAME: ) #[[ATTR0]] comdat - [[clang::no_outline]] static int static_func(int x) { +// CXX-SAME: ) #[[ATTR1]] comdat + ATTR static int static_func(int x) { return x; } }; template <typename T> struct templated_struct { - [[clang::no_outline]] T member_func(T x) { + ATTR T member_func(T x) { return x; } - [[clang::no_outline]] static T static_func(T x) { + ATTR static T static_func(T x) { return x; } }; // CXX-LABEL: define weak_odr noundef i32 @_ZN16templated_structIiE11member_funcEi( -// CXX-SAME: ) #[[ATTR0]] comdat +// CXX-SAME: ) #[[ATTR1]] comdat // CXX-LABEL: define weak_odr noundef i32 @_ZN16templated_structIiE11static_funcEi( -// CXX-SAME: ) #[[ATTR0]] comdat +// CXX-SAME: ) #[[ATTR1]] comdat template struct templated_struct<int>; -#if __cplusplus >= 202302L +// CXX-LABEL: define dso_local noundef i32 @_Z16func_with_lambdai( +// CXX-ATTR-SAME: ) #[[ATTR2]] +// CXX-ARG-SAME: ) #[[ATTR1]] +// CXX-NONE-SAME: ) #[[ATTR1]] int func_with_lambda(int x) { - // CXX23-LABEL: define internal noundef i32 @"_ZZ16func_with_lambdaiENK3$_0clEv"( - // CXX23-SAME: ) #[[ATTR0]] - auto lambda = [x][[clang::no_outline]]() -> int { + +// CXX-LABEL: define internal noundef i32 @"_ZZ16func_with_lambdaiENK3$_0clEv"( +// CXX-SAME: ) #[[ATTR1]] + auto lambda = [x] ATTR () -> int { return x; }; return lambda(); } #endif -#endif -// C: attributes #[[ATTR0]] = { -// C-SAME: nooutline +// C: attributes #[[ATTR1]] = { +// C-ATTR-SAME: nooutline +// C-ARG-SAME: nooutline +// C-NONE-NOT: nooutline // C-SAME: } -// CXX: attributes #[[ATTR0]] = { -// CXX-SAME: nooutline -// CXX-SAME: } +// C-ATTR: attributes #[[ATTR2]] = { +// C-ATTR-NOT: nooutline +// C-ATTR-SAME: } // CXX: attributes #[[ATTR1]] = { -// CXX-SAME: nooutline +// CXX-ATTR-SAME: nooutline +// CXX-ARG-SAME: nooutline +// CXX-NONE-NOT: nooutline // CXX-SAME: } + +// CXX: attributes #[[ATTR2]] = { +// CXX-ATTR-NOT: nooutline +// CXX-ARG-SAME: nooutline +// CXX-NONE-NOT: nooutline +// CXX-SAME: } + +// CXX-ATTR: attributes #[[ATTR3]] = { +// CXX-ATTR-SAME: nooutline +// CXX-ATTR-SAME: } diff --git a/clang/test/CodeGenObjC/attr-no-outline.m b/clang/test/CodeGenObjC/attr-no-outline.m index 16d1a9eb867a0..8819f1d81107c 100644 --- a/clang/test/CodeGenObjC/attr-no-outline.m +++ b/clang/test/CodeGenObjC/attr-no-outline.m @@ -1,9 +1,28 @@ -// RUN: %clang_cc1 -emit-llvm %s -triple x86_64-unknown-linux-gnu -o - | FileCheck %s --check-prefix=OBJC -// RUN: %clang_cc1 -emit-llvm -x objective-c++ %s -triple x86_64-unknown-linux-gnu -o - | FileCheck %s --check-prefix=OBJCXX +// RUN: %clang_cc1 -emit-llvm %s -triple x86_64-unknown-linux-gnu -o - -DTEST_ATTR | FileCheck %s --check-prefixes=OBJC,OBJC-ATTR +// RUN: %clang_cc1 -emit-llvm %s -triple x86_64-unknown-linux-gnu -o - -mno-outline | FileCheck %s --check-prefixes=OBJC,OBJC-ARG +// RUN: %clang_cc1 -emit-llvm %s -triple x86_64-unknown-linux-gnu -o - | FileCheck %s --check-prefixes=OBJC,OBJC-NONE + +// RUN: %clang_cc1 -emit-llvm -x objective-c++ %s -triple x86_64-unknown-linux-gnu -o - -DTEST_ATTR | FileCheck %s --check-prefixes=OBJCXX,OBJCXX-ATTR +// RUN: %clang_cc1 -emit-llvm -x objective-c++ %s -triple x86_64-unknown-linux-gnu -o - -mno-outline | FileCheck %s --check-prefixes=OBJCXX,OBJCXX-ARG +// RUN: %clang_cc1 -emit-llvm -x objective-c++ %s -triple x86_64-unknown-linux-gnu -o - | FileCheck %s --check-prefixes=OBJCXX,OBJCXX-NONE + +// This test checks that: +// - [[clang::no_outline]] adds the nooutline IR attribute to specific definitions +// - `-mno-outline` adds the nooutline IR attribute to all definitions +// - Lack of either does not add nooutline IR attribute + + +#ifdef TEST_ATTR +#define ATTR [[clang::no_outline]] +#else +#define ATTR +#endif @interface Test - (int)method:(int)x; +- (int)method_no_attr:(int)x; + (int)static_method:(int)x; ++ (int)static_method_no_attr:(int)x; @end @implementation Test @@ -13,7 +32,20 @@ @implementation Test // OBJCXX-LABEL: define internal noundef i32 @"\01-[Test method:]"( // OBJCXX: ) #[[ATTR0:[0-9]+]] { -- (int)method:(int)x [[clang::no_outline]] { +- (int)method:(int)x ATTR { + return x; +} + +// OBJC-LABEL: define internal i32 @"\01-[Test method_no_attr:]"( +// OBJC-ATTR: ) #[[ATTR1:[0-9]+]] { +// OBJC-ARG: ) #[[ATTR0]] { +// OBJC-NONE: ) #[[ATTR0]] { + +// OBJCXX-LABEL: define internal noundef i32 @"\01-[Test method_no_attr:]"( +// OBJCXX-ATTR: ) #[[ATTR1:[0-9]+]] { +// OBJCXX-ARG: ) #[[ATTR0]] { +// OBJCXX-NONE: ) #[[ATTR0]] { +- (int)method_no_attr:(int) x { return x; } @@ -22,19 +54,44 @@ - (int)method:(int)x [[clang::no_outline]] { // OBJCXX-LABEL: define internal noundef i32 @"\01+[Test static_method:]"( // OBJCXX: ) #[[ATTR0]] { -+ (int)static_method:(int)x [[clang::no_outline]] { ++ (int)static_method:(int)x ATTR { + return x; +} + + +// OBJC-LABEL: define internal i32 @"\01+[Test static_method_no_attr:]"( +// OBJC-ATTR: ) #[[ATTR1]] { +// OBJC-ARG: ) #[[ATTR0]] { +// OBJC-NONE: ) #[[ATTR0]] { + + +// OBJCXX-LABEL: define internal noundef i32 @"\01+[Test static_method_no_attr:]"( +// OBJCXX-ATTR: ) #[[ATTR1]] { +// OBJCXX-ARG: ) #[[ATTR0]] { +// OBJCXX-NONE: ) #[[ATTR0]] { + ++ (int)static_method_no_attr:(int)x { return x; } @end // OBJC: attributes #[[ATTR0]] = { -// OBJC-SAME: nooutline +// OBJC-ATTR-SAME: nooutline +// OBJC-ARG-SAME: nooutline +// OBJC-NONE-NOT: nooutline // OBJC-SAME: } +// OBJC-ATTR: attributes #[[ATTR1]] = { +// OBJC-ATTR-NOT: nooutline +// OBJC-ATTR-SAME: } + // OBJCXX: attributes #[[ATTR0]] = { -// OBJCXX-SAME: nooutline +// OBJCXX-ATTR-SAME: nooutline +// OBJCXX-ARG-SAME: nooutline +// OBJCXX-NONE-NOT: nooutline // OBJCXX-SAME: } - - +// OBJCXX-ATTR: attributes #[[ATTR1]] = { +// OBJCXX-ATTR-NOT: nooutline +// OBJCXX-ATTR-SAME: } diff --git a/clang/test/Driver/aarch64-outliner.c b/clang/test/Driver/aarch64-outliner.c index 5ed822f122fc4..4d5b7321e330f 100644 --- a/clang/test/Driver/aarch64-outliner.c +++ b/clang/test/Driver/aarch64-outliner.c @@ -3,4 +3,4 @@ // ON: "-mllvm" "-enable-machine-outliner" // RUN: %clang --target=aarch64 -moutline -mno-outline -S %s -### 2>&1 | FileCheck %s -check-prefix=OFF // RUN: %clang --target=aarch64_be -moutline -mno-outline -S %s -### 2>&1 | FileCheck %s -check-prefix=OFF -// OFF: "-mllvm" "-enable-machine-outliner=never" +// OFF: "-mno-outline" "-mllvm" "-enable-machine-outliner=never" diff --git a/clang/test/Driver/arm-machine-outliner.c b/clang/test/Driver/arm-machine-outliner.c index a1e705cb60a1b..efa29d2ab8450 100644 --- a/clang/test/Driver/arm-machine-outliner.c +++ b/clang/test/Driver/arm-machine-outliner.c @@ -3,6 +3,6 @@ // RUN: %clang -target armv7-linux-gnueabihf -flto -moutline %s -### 2>&1 | FileCheck %s -check-prefix=ON-LTO // ON-LTO: "-plugin-opt=-enable-machine-outliner" // RUN: %clang -target armv7-linux-gnueabihf -moutline -mno-outline -c %s -### 2>&1 | FileCheck %s -check-prefix=OFF -// OFF: "-mllvm" "-enable-machine-outliner=never" +// OFF: "-mno-outline" "-mllvm" "-enable-machine-outliner=never" // RUN: %clang -target armv7-linux-gnueabihf -flto -moutline -mno-outline %s -### 2>&1 | FileCheck %s -check-prefix=OFF-LTO // OFF-LTO: "-plugin-opt=-enable-machine-outliner=never" diff --git a/clang/test/Driver/riscv-outliner.c b/clang/test/Driver/riscv-outliner.c index 9e9905ab4fd8a..fa69977331e13 100644 --- a/clang/test/Driver/riscv-outliner.c +++ b/clang/test/Driver/riscv-outliner.c @@ -4,4 +4,4 @@ // RUN: %clang --target=riscv32 -moutline -mno-outline -S %s -### 2>&1 | FileCheck %s -check-prefix=OFF // RUN: %clang --target=riscv64 -moutline -mno-outline -S %s -### 2>&1 | FileCheck %s -check-prefix=OFF -// OFF: "-mllvm" "-enable-machine-outliner=never" +// OFF: "-mno-outline" "-mllvm" "-enable-machine-outliner=never" diff --git a/clang/test/Driver/x86-outliner.c b/clang/test/Driver/x86-outliner.c index e2af85d3d16ab..7da56ac93fa5e 100644 --- a/clang/test/Driver/x86-outliner.c +++ b/clang/test/Driver/x86-outliner.c @@ -4,4 +4,4 @@ // RUN: %clang --target=i386 -moutline -mno-outline -S %s -### 2>&1 | FileCheck %s -check-prefix=OFF // RUN: %clang --target=x86_64 -moutline -mno-outline -S %s -### 2>&1 | FileCheck %s -check-prefix=OFF -// OFF: "-mllvm" "-enable-machine-outliner=never" +// OFF: "-mno-outline" "-mllvm" "-enable-machine-outliner=never" _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
