https://github.com/shivaramaarao updated https://github.com/llvm/llvm-project/pull/230007
>From 66eed85a0d712d466b323454341f136b2d3c3bae Mon Sep 17 00:00:00 2001 From: Shivarama Rao <[email protected]> Date: Thu, 8 Oct 2026 12:32:21 +0530 Subject: [PATCH] [flang] Add -f[no]keep-inline-functions option Treat definitions marked alwaysinline (!dir$ inlinealways) as the functions inlined, and keep those definitions after they are inlined into every caller. Restrict definition retention to the current translation unit, ensuring that definitions from linked bitcode (BC) files are not preserved. added testcases to test this functionality. Assisted by Cursor to generate the testcases. Fixes #223359 --- clang/include/clang/Options/Options.td | 4 +- clang/lib/Driver/ToolChains/Flang.cpp | 2 + .../include/flang/Frontend/CodeGenOptions.def | 1 + flang/lib/Frontend/CompilerInvocation.cpp | 4 ++ flang/lib/Frontend/FrontendActions.cpp | 23 ++++++++ .../keep-inline-functions-link.f90 | 33 ++++++++++++ .../Integration/keep-inline-functions.f90 | 52 +++++++++++++++++++ flang/test/Integration/keep-inline-lib.f90 | 5 ++ 8 files changed, 122 insertions(+), 2 deletions(-) create mode 100644 flang/test/Integration/keep-inline-functions-link.f90 create mode 100644 flang/test/Integration/keep-inline-functions.f90 create mode 100644 flang/test/Integration/keep-inline-lib.f90 diff --git a/clang/include/clang/Options/Options.td b/clang/include/clang/Options/Options.td index 56194af32f68f3..72a0a0ee05c95c 100644 --- a/clang/include/clang/Options/Options.td +++ b/clang/include/clang/Options/Options.td @@ -2598,8 +2598,8 @@ defm keep_persistent_storage_variables : BoolFOption<"keep-persistent-storage-va " keeping all variables that have a persistent storage duration, including global, static and thread-local variables, to guarantee that they can be directly addressed">>; defm keep_inline_functions : BoolFOption<"keep-inline-functions", CodeGenOpts<"KeepInlineFunctions">, DefaultFalse, - PosFlag<SetTrue, [], [ClangOption, CC1Option], "Keep">, - NegFlag<SetFalse, [], [ClangOption], "Don't keep">, + PosFlag<SetTrue, [], [ClangOption, CC1Option, FlangOption, FC1Option], "Keep">, + NegFlag<SetFalse, [], [ClangOption, FlangOption], "Don't keep">, BothFlags<[], [], " inline functions whose definition is owned by this translation unit, even if they are inlined into all callers.">>; defm fixed_point : BoolFOption<"fixed-point", diff --git a/clang/lib/Driver/ToolChains/Flang.cpp b/clang/lib/Driver/ToolChains/Flang.cpp index 0e6858d3bb6452..4f64b3ba050c1b 100644 --- a/clang/lib/Driver/ToolChains/Flang.cpp +++ b/clang/lib/Driver/ToolChains/Flang.cpp @@ -355,6 +355,8 @@ void Flang::addCodegenOptions(const ArgList &Args, Args.addOptInFlag(CmdArgs, options::OPT_fexperimental_loop_fusion, options::OPT_fno_experimental_loop_fusion); + Args.addOptInFlag(CmdArgs, options::OPT_fkeep_inline_functions, + options::OPT_fno_keep_inline_functions); Args.AddLastArg(CmdArgs, options::OPT_ffp_sum_reassociation, options::OPT_fno_fp_sum_reassociation); diff --git a/flang/include/flang/Frontend/CodeGenOptions.def b/flang/include/flang/Frontend/CodeGenOptions.def index d49a7f3647eec5..4cc8cbd008d8a3 100644 --- a/flang/include/flang/Frontend/CodeGenOptions.def +++ b/flang/include/flang/Frontend/CodeGenOptions.def @@ -30,6 +30,7 @@ ENUM_CODEGENOPT(ProfileInstr, llvm::driver::ProfileInstrKind, 2, llvm::driver::P /// Choose profile kind for PGO use compilation. ENUM_CODEGENOPT(ProfileUse, llvm::driver::ProfileInstrKind, 2, llvm::driver::ProfileInstrKind::ProfileNone) +CODEGENOPT(KeepInlineFunctions, 1, 0) ///< -fkeep-inline-functions. CODEGENOPT(InstrumentFunctions, 1, 0) ///< Set when -finstrument_functions is ///< enabled on the compile step. diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp index b76b38ff6497f7..9e5d805f4ca683 100644 --- a/flang/lib/Frontend/CompilerInvocation.cpp +++ b/flang/lib/Frontend/CompilerInvocation.cpp @@ -380,6 +380,10 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts, if (args.hasArg(clang::options::OPT_finstrument_functions)) opts.InstrumentFunctions = 1; + // -fkeep-inline-functions. The driver forwards only the positive flag. + opts.KeepInlineFunctions = + args.hasArg(clang::options::OPT_fkeep_inline_functions); + // -fno-integrated-as: emit GNU Assembler compatible assembly. if (!args.hasFlag(clang::options::OPT_fintegrated_as, clang::options::OPT_fno_integrated_as, true)) diff --git a/flang/lib/Frontend/FrontendActions.cpp b/flang/lib/Frontend/FrontendActions.cpp index 35c2b9ec881e8d..8e409ff47db1f1 100644 --- a/flang/lib/Frontend/FrontendActions.cpp +++ b/flang/lib/Frontend/FrontendActions.cpp @@ -1430,6 +1430,29 @@ void CodeGenAction::executeAction() { llvmModule->setTargetTriple(theTriple); llvmModule->setDataLayout(targetMachine.createDataLayout()); + // -fkeep-inline-functions: retain definitions of inline functions (those + // marked alwaysinline) after they have been inlined into every caller. + // On ELF this uses llvm.compiler.used so the compiler keeps the definition + // but the linker may still drop it. Other object formats use llvm.used. + // This is matching Clang functionality.Only functions defined in this + // translation unit are considered. + if (codeGenOpts.KeepInlineFunctions) { + llvm::SmallVector<llvm::GlobalValue *, 8> kept; + for (llvm::Function &func : *llvmModule) { + if (func.isDeclaration() || func.hasAvailableExternallyLinkage()) + continue; + if (!func.hasFnAttribute(llvm::Attribute::AlwaysInline)) + continue; + kept.push_back(&func); + } + if (!kept.empty()) { + if (theTriple.isOSBinFormatELF()) + llvm::appendToCompilerUsed(*llvmModule, kept); + else + llvm::appendToUsed(*llvmModule, kept); + } + } + // Link in builtin bitcode libraries if (!codeGenOpts.BuiltinBCLibs.empty()) linkBuiltinBCLibs(); diff --git a/flang/test/Integration/keep-inline-functions-link.f90 b/flang/test/Integration/keep-inline-functions-link.f90 new file mode 100644 index 00000000000000..1cf7a978b706f3 --- /dev/null +++ b/flang/test/Integration/keep-inline-functions-link.f90 @@ -0,0 +1,33 @@ +! -fkeep-inline-functions must only record alwaysinline definitions that +! belong to this translation unit. A builtin bitcode library brought in via +! -mlink-builtin-bitcode can itself contain an alwaysinline function (for +! its own, unrelated reasons); that function was never named by a +! !DIR$ INLINEALWAYS in this file and must not be added to llvm.used / +! llvm.compiler.used because of this flag. This requires the check to run +! before the builtin bitcode library is linked into the module. + +! RUN: %flang -emit-llvm -c -o %t.bc %S/keep-inline-lib.f90 +! RUN: %flang_fc1 -emit-llvm -O2 -fkeep-inline-functions -mlink-builtin-bitcode %t.bc -o - %s | FileCheck %s + +program main + external lib_add_two + integer :: lib_add_two + integer :: n + n = lib_add_two(5) + n = own_add_three(n) + print *, n +contains + integer function own_add_three(n) + !dir$ inlinealways own_add_three + integer :: n + own_add_three = n + 3 + end function +end program + +! The list has exactly one entry: this translation unit's own +! own_add_three, and not the linked library's lib_add_two. +! CHECK: @llvm.{{(compiler.)?}}used = appending global [1 x ptr] [ptr @_QFPown_add_three] + +! lib_add_two (from the linked bitcode library) is still called, unaffected +! by the flag. +! CHECK: call {{.*}}@lib_add_two_( diff --git a/flang/test/Integration/keep-inline-functions.f90 b/flang/test/Integration/keep-inline-functions.f90 new file mode 100644 index 00000000000000..270edcc2471d7b --- /dev/null +++ b/flang/test/Integration/keep-inline-functions.f90 @@ -0,0 +1,52 @@ +! RUN: %flang -### -fkeep-inline-functions %s 2>&1 | FileCheck %s --check-prefix=DRIVER-KEEP +! Neither flag is the default: the driver forwards nothing to fc1. +! RUN: %flang -### %s 2>&1 | FileCheck %s --check-prefix=DRIVER-NOKEEP +! RUN: %flang -### -fno-keep-inline-functions %s 2>&1 | FileCheck %s --check-prefix=DRIVER-NOKEEP +! RUN: %flang -### -fkeep-inline-functions -fno-keep-inline-functions %s 2>&1 | FileCheck %s --check-prefix=DRIVER-NOKEEP +! RUN: %flang -### -fno-keep-inline-functions -fkeep-inline-functions %s 2>&1 | FileCheck %s --check-prefix=DRIVER-KEEP + +! DRIVER-KEEP: "-fc1" +! DRIVER-KEEP-SAME: "-fkeep-inline-functions" +! DRIVER-NOKEEP: "-fc1" +! DRIVER-NOKEEP-NOT: "-fkeep-inline-functions" +! DRIVER-NOKEEP-NOT: "-fno-keep-inline-functions" + +! Without the flag, an alwaysinline contained procedure is inlined and deleted. +! RUN: %flang_fc1 -emit-llvm -O2 -o - %s | FileCheck %s --check-prefix=DEFAULT +! -fkeep-inline-functions retains that definition, matching Clang's retention +! of inline functions owned by this translation unit. +! RUN: %flang_fc1 -emit-llvm -O2 -fkeep-inline-functions -o - %s | FileCheck %s --check-prefix=KEEP + +subroutine test_always(n) + integer :: n + n = add_two(n) +contains + integer function add_two(n) + !dir$ inlinealways add_two + integer :: n + add_two = n + 2 + end function +end subroutine + +subroutine test_plain(n) + integer :: n + n = add_one(n) +contains + integer function add_one(n) + integer :: n + add_one = n + 1 + end function +end subroutine + +! DEFAULT-LABEL: define void @test_always_( +! DEFAULT-NOT: @_QFtest_alwaysPadd_two( +! DEFAULT-NOT: define {{.*}}@_QFtest_alwaysPadd_two( + +! KEEP: @llvm.{{(compiler.)?}}used = {{.*}}@_QFtest_alwaysPadd_two +! KEEP-LABEL: define void @test_always_( +! KEEP-NOT: call {{.*}}@_QFtest_alwaysPadd_two( +! KEEP: define internal {{.*}}@_QFtest_alwaysPadd_two( +! A contained procedure that is not marked inline is still deleted. +! KEEP-LABEL: define void @test_plain_( +! KEEP-NOT: @_QFtest_plainPadd_one( +! KEEP-NOT: define {{.*}}@_QFtest_plainPadd_one( diff --git a/flang/test/Integration/keep-inline-lib.f90 b/flang/test/Integration/keep-inline-lib.f90 new file mode 100644 index 00000000000000..6bdd17faf26f56 --- /dev/null +++ b/flang/test/Integration/keep-inline-lib.f90 @@ -0,0 +1,5 @@ +integer function lib_add_two(n) + !dir$ inlinealways lib_add_two + integer :: n + lib_add_two = n + 2 +end function _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
