https://github.com/mylai-mtk created
https://github.com/llvm/llvm-project/pull/127616
The `-fcf-protection` flag is now also used to enable CFI features for the
RISC-V target, so it's not suitable to define `__CET__` solely based on the
flag anymore. This patch moves the definition of the `__CET__` macro into X86
target hook, so only X86 targets with the `-fcf-protection` flag would enable
the `__CET__` macro.
>From 348e70f60f29e7fbc0f16b0f0125853cdd832b03 Mon Sep 17 00:00:00 2001
From: Ming-Yi Lai <ming-yi....@mediatek.com>
Date: Tue, 18 Feb 2025 18:30:35 +0800
Subject: [PATCH] [clang][X86] Only define __CET__ macro for X86 targets
The `-fcf-protection` flag is now also used to enable CFI features for the
RISC-V target, so it's not suitable to define `__CET__` solely based on the
flag anymore. This patch moves the definition of the `__CET__` macro into X86
target hook, so only X86 targets with the `-fcf-protection` flag would enable
the `__CET__` macro.
---
clang/lib/Basic/Targets/X86.cpp | 4 ++++
clang/lib/Frontend/CompilerInvocation.cpp | 11 -----------
clang/test/Preprocessor/riscv-cf-protection-return.c | 2 ++
3 files changed, 6 insertions(+), 11 deletions(-)
diff --git a/clang/lib/Basic/Targets/X86.cpp b/clang/lib/Basic/Targets/X86.cpp
index 84a05cec04e7f..e4d3ad04fe9de 100644
--- a/clang/lib/Basic/Targets/X86.cpp
+++ b/clang/lib/Basic/Targets/X86.cpp
@@ -1109,6 +1109,10 @@ void X86TargetInfo::getTargetDefines(const LangOptions
&Opts,
if (HasFloat128)
Builder.defineMacro("__SIZEOF_FLOAT128__", "16");
+
+ if (Opts.CFProtectionReturn || Opts.CFProtectionBranch)
+ Builder.defineMacro("__CET__", Twine{(Opts.CFProtectionReturn << 1) |
+ Opts.CFProtectionBranch});
}
bool X86TargetInfo::isValidFeatureName(StringRef Name) const {
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp
b/clang/lib/Frontend/CompilerInvocation.cpp
index b9a5c0589ebc4..4eb743acf327f 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -4776,17 +4776,6 @@ static bool ParsePreprocessorArgs(PreprocessorOptions
&Opts, ArgList &Args,
}
}
- // Add the __CET__ macro if a CFProtection option is set.
- if (const Arg *A = Args.getLastArg(OPT_fcf_protection_EQ)) {
- StringRef Name = A->getValue();
- if (Name == "branch")
- Opts.addMacroDef("__CET__=1");
- else if (Name == "return")
- Opts.addMacroDef("__CET__=2");
- else if (Name == "full")
- Opts.addMacroDef("__CET__=3");
- }
-
// Add macros from the command line.
for (const auto *A : Args.filtered(OPT_D, OPT_U)) {
if (A->getOption().matches(OPT_D))
diff --git a/clang/test/Preprocessor/riscv-cf-protection-return.c
b/clang/test/Preprocessor/riscv-cf-protection-return.c
index 3a93a88fa6839..a4cbaa1edf68c 100644
--- a/clang/test/Preprocessor/riscv-cf-protection-return.c
+++ b/clang/test/Preprocessor/riscv-cf-protection-return.c
@@ -40,5 +40,7 @@
// RUN: -menable-experimental-extensions -fcf-protection=full -E -dM %s -o - \
// RUN: | FileCheck --check-prefixes=SHSTK-MACRO %s
+// SHSTK-MACRO-NOT: __CET__
// SHSTK-MACRO: __riscv_shadow_stack 1{{$}}
+// SHSTK-MACRO-NOT: __CET__
// NO-MACRO-NOT: __riscv_shadow_stack
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