775a9483e5
On ELF targets, if a function has uwtable or personality, or does not have nounwind (`needsUnwindTableEntry`), it marks that `.eh_frame` is needed in the module. Then, a function gets `.eh_frame` if `needsUnwindTableEntry` or `-g[123]` is specified. (i.e. If -g[123], every function gets `.eh_frame`. This behavior is strange but that is the status quo on GCC and Clang.) Let's take asan as an example. Other sanitizers are similar. `asan.module_[cd]tor` has no attribute. `needsUnwindTableEntry` returns true, so every function gets `.eh_frame` if `-g[123]` is specified. This is the root cause that `-fno-exceptions -fno-asynchronous-unwind-tables -g` produces .debug_frame while `-fno-exceptions -fno-asynchronous-unwind-tables -g -fsanitize=address` produces .eh_frame. This patch * sets the nounwind attribute on sanitizer module ctor/dtor. * let Clang emit a module flag metadata "uwtable" for -fasynchronous-unwind-tables. If "uwtable" is set, sanitizer module ctor/dtor additionally get the uwtable attribute. The "uwtable" mechanism is generic: synthesized functions not cloned/specialized from existing ones should consider `Function::createWithDefaultAttr` instead of `Function::create` if they want to get some default attributes which have more of module semantics. Other candidates: "frame-pointer" (https://github.com/ClangBuiltLinux/linux/issues/955 https://github.com/ClangBuiltLinux/linux/issues/1238), dso_local, etc. Differential Revision: https://reviews.llvm.org/D100251
12 lines
1.1 KiB
C++
12 lines
1.1 KiB
C++
// Test that on Linux asan constructor is placed in a comdat iff globals-gc is on.
|
|
// Even if there are no globals in the module.
|
|
|
|
// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITHOUT-GC
|
|
// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fdata-sections -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITH-GC
|
|
// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fno-integrated-as -fdata-sections -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITHOUT-GC
|
|
// RUN: %clang_cc1 -fsanitize=address -fsanitize-address-globals-dead-stripping -fno-integrated-as -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITHOUT-GC
|
|
// RUN: %clang_cc1 -fsanitize=address -fdata-sections -emit-llvm -o - -triple x86_64-linux %s | FileCheck %s --check-prefix=WITHOUT-GC
|
|
|
|
// WITH-GC: define internal void @asan.module_ctor() #[[#]] comdat {
|
|
// WITHOUT-GC: define internal void @asan.module_ctor() #[[#]] {
|