Commit 0c3a02b8 authored by Fangrui Song's avatar Fangrui Song
Browse files

Function multi-versioning: disable ifunc for ELF targets other than glibc/Android/FreeBSD 

Generalize D127933 (Fuchsia special case) to other ELF targets. Ensure
that musl, NetBSD, OpenBSD, etc do not get ifunc codegen which is
unsupported in their rtld.

Link: https://discourse.llvm.org/t/does-ifunc-use-from-llvm-require-os-support/67628
Close: https://github.com/llvm/llvm-project/issues/64631
parent ecc4ef9f

clang/include/clang/Basic/TargetInfo.h

+3 −1
Original line number Diff line number Diff line
@@ -1414,7 +1414,9 @@ public: 


  /// Identify whether this target supports IFuncs.

  bool supportsIFunc() const {

    return getTriple().isOSBinFormatELF() && !getTriple().isOSFuchsia();

    return getTriple().isOSBinFormatELF() &&

           ((getTriple().isOSLinux() && !getTriple().isMusl()) ||

            getTriple().isOSFreeBSD());

  }



  // Validate the contents of the __builtin_cpu_supports(const char*)

clang/test/CodeGen/attr-target-mv-va-args.c

+22 −20
Original line number Diff line number Diff line 
// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm %s -o - | FileCheck %s --check-prefix=LINUX

// RUN: %clang_cc1 -triple x86_64-linux-gnu -emit-llvm %s -o - | FileCheck %s --check-prefix=IFUNC-ELF

// RUN: %clang_cc1 -triple x86_64-pc-freebsd -emit-llvm %s -o - | FileCheck %s --check-prefix=IFUNC-ELF

// RUN: %clang_cc1 -triple x86_64-windows-pc -emit-llvm %s -o - | FileCheck %s --check-prefixes=NO-IFUNC,WINDOWS

// RUN: %clang_cc1 -triple x86_64-fuchsia -emit-llvm %s -o - | FileCheck %s --check-prefixes=NO-IFUNC,FUCHSIA

// RUN: %clang_cc1 -triple x86_64-linux-musl -emit-llvm %s -o - | FileCheck %s --check-prefixes=NO-IFUNC,NO-IFUNC-ELF

// RUN: %clang_cc1 -triple x86_64-fuchsia -emit-llvm %s -o - | FileCheck %s --check-prefixes=NO-IFUNC,NO-IFUNC-ELF

int __attribute__((target("sse4.2"))) foo(int i, ...) { return 0; }

int __attribute__((target("arch=sandybridge"))) foo(int i, ...);

int __attribute__((target("arch=ivybridge"))) foo(int i, ...) {return 1;}
@@ -10,23 +12,23 @@ int bar(void) { 
  return foo(1, 'a', 1.1) + foo(2, 2.2, "asdf");

}



// LINUX: @foo.ifunc = weak_odr ifunc i32 (i32, ...), ptr @foo.resolver

// LINUX: define{{.*}} i32 @foo.sse4.2(i32 noundef %i, ...)

// LINUX: ret i32 0

// LINUX: define{{.*}} i32 @foo.arch_ivybridge(i32 noundef %i, ...)

// LINUX: ret i32 1

// LINUX: define{{.*}} i32 @foo(i32 noundef %i, ...)

// LINUX: ret i32 2

// LINUX: define{{.*}} i32 @bar()

// LINUX: call i32 (i32, ...) @foo.ifunc(i32 noundef 1, i32 noundef 97, double

// LINUX: call i32 (i32, ...) @foo.ifunc(i32 noundef 2, double noundef 2.2{{[0-9Ee+]+}}, ptr noundef

// IFUNC-ELF: @foo.ifunc = weak_odr ifunc i32 (i32, ...), ptr @foo.resolver

// IFUNC-ELF: define{{.*}} i32 @foo.sse4.2(i32 noundef %i, ...)

// IFUNC-ELF: ret i32 0

// IFUNC-ELF: define{{.*}} i32 @foo.arch_ivybridge(i32 noundef %i, ...)

// IFUNC-ELF: ret i32 1

// IFUNC-ELF: define{{.*}} i32 @foo(i32 noundef %i, ...)

// IFUNC-ELF: ret i32 2

// IFUNC-ELF: define{{.*}} i32 @bar()

// IFUNC-ELF: call i32 (i32, ...) @foo.ifunc(i32 noundef 1, i32 noundef 97, double

// IFUNC-ELF: call i32 (i32, ...) @foo.ifunc(i32 noundef 2, double noundef 2.2{{[0-9Ee+]+}}, ptr noundef



// LINUX: define weak_odr ptr @foo.resolver() comdat

// LINUX: ret ptr @foo.arch_sandybridge

// LINUX: ret ptr @foo.arch_ivybridge

// LINUX: ret ptr @foo.sse4.2

// LINUX: ret ptr @foo

// LINUX: declare i32 @foo.arch_sandybridge(i32 noundef, ...)

// IFUNC-ELF: define weak_odr ptr @foo.resolver() comdat

// IFUNC-ELF: ret ptr @foo.arch_sandybridge

// IFUNC-ELF: ret ptr @foo.arch_ivybridge

// IFUNC-ELF: ret ptr @foo.sse4.2

// IFUNC-ELF: ret ptr @foo

// IFUNC-ELF: declare i32 @foo.arch_sandybridge(i32 noundef, ...)



// NO-IFUNC: define dso_local i32 @foo.sse4.2(i32 noundef %i, ...)

// NO-IFUNC: ret i32 0
@@ -39,10 +41,10 @@ int bar(void) { 
// NO-IFUNC: call i32 (i32, ...) @foo.resolver(i32 noundef 2, double noundef 2.2{{[0-9Ee+]+}}, ptr noundef



// WINDOWS: define weak_odr dso_local i32 @foo.resolver(i32 %0, ...) comdat

// FUCHSIA: define weak_odr i32 @foo.resolver(i32 %0, ...) comdat

// NO-IFUNC-ELF: define weak_odr i32 @foo.resolver(i32 %0, ...) comdat

// NO-IFUNC: musttail call i32 (i32, ...) @foo.arch_sandybridge

// NO-IFUNC: musttail call i32 (i32, ...) @foo.arch_ivybridge

// NO-IFUNC: musttail call i32 (i32, ...) @foo.sse4.2

// NO-IFUNC: musttail call i32 (i32, ...) @foo

// WINDOWS: declare dso_local i32 @foo.arch_sandybridge(i32 noundef, ...)

// FUCHSIA: declare i32 @foo.arch_sandybridge(i32 noundef, ...)
 
// NO-IFUNC-ELF: declare i32 @foo.arch_sandybridge(i32 noundef, ...)

clang/test/CodeGen/unique-internal-linkage-names.cpp

+2 −2
Original line number Diff line number Diff line 
// This test checks if internal linkage symbols get unique names with

// -funique-internal-linkage-names option.

// RUN: %clang_cc1 -triple x86_64 -x c++ -S -emit-llvm -o - < %s | FileCheck %s --check-prefix=PLAIN

// RUN: %clang_cc1 -triple x86_64 -x c++  -S -emit-llvm -funique-internal-linkage-names -o - < %s | FileCheck %s --check-prefix=UNIQUE

// RUN: %clang_cc1 -triple x86_64-linux-gnu -x c++ -S -emit-llvm -o - < %s | FileCheck %s --check-prefix=PLAIN

// RUN: %clang_cc1 -triple x86_64-linux-gnu -x c++  -S -emit-llvm -funique-internal-linkage-names -o - < %s | FileCheck %s --check-prefix=UNIQUE



static int glob;

static int foo() {