https://github.com/kees created https://github.com/llvm/llvm-project/pull/89707
When building the Linux kernel for i386, the -mregparm=3 option is enabled.
Crashes were observed in the sanitizer handler functions, and the problem was
found to be mismatched calling convention.
As was fixed in commit c167c0a4dcdb ("[BuildLibCalls] infer inreg param attrs
from NumRegisterParameters"), call arguments need to be marked as "in register"
when -mregparm is set. Use the same helper developed there to update the
function arguments.
Since CreateRuntimeFunction() is actually part of CodeGenModule, storage of the
-mregparm value is also moved to the constructor, as doing this in Release() is
too late.
Fixes: https://github.com/llvm/llvm-project/issues/89670
>From c061c8f49f2b916bb5e60ec35d3e448ac13f2b72 Mon Sep 17 00:00:00 2001
From: Kees Cook <keesc...@chromium.org>
Date: Mon, 22 Apr 2024 17:53:32 -0700
Subject: [PATCH] [CodeGen][i386] Move -mregparm storage earlier and fix
Runtime calls
When building the Linux kernel for i386, the -mregparm=3 option is
enabled. Crashes were observed in the sanitizer handler functions,
and the problem was found to be mismatched calling convention.
As was fixed in commit c167c0a4dcdb ("[BuildLibCalls] infer inreg param
attrs from NumRegisterParameters"), call arguments need to be marked as
"in register" when -mregparm is set. Use the same helper developed there
to update the function arguments.
Since CreateRuntimeFunction() is actually part of CodeGenModule, storage
of the -mregparm value is also moved to the constructor, as doing this
in Release() is too late.
Fixes: https://github.com/llvm/llvm-project/issues/89670
---
clang/lib/CodeGen/CodeGenModule.cpp | 12 +++++++-----
llvm/include/llvm/Transforms/Utils/BuildLibCalls.h | 3 +++
llvm/lib/Transforms/Utils/BuildLibCalls.cpp | 2 +-
3 files changed, 11 insertions(+), 6 deletions(-)
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp
b/clang/lib/CodeGen/CodeGenModule.cpp
index 0c447b20cef40d..c314cd9e2e9f4c 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -73,6 +73,7 @@
#include "llvm/Support/xxhash.h"
#include "llvm/TargetParser/Triple.h"
#include "llvm/TargetParser/X86TargetParser.h"
+#include "llvm/Transforms/Utils/BuildLibCalls.h"
#include <optional>
using namespace clang;
@@ -442,6 +443,11 @@ CodeGenModule::CodeGenModule(ASTContext &C,
}
ModuleNameHash = llvm::getUniqueInternalLinkagePostfix(Path);
}
+
+ // Record mregparm value now so it is visible through all of codegen.
+ if (Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
+ getModule().addModuleFlag(llvm::Module::Error, "NumRegisterParameters",
+ CodeGenOpts.NumRegisterParameters);
}
CodeGenModule::~CodeGenModule() {}
@@ -980,11 +986,6 @@ void CodeGenModule::Release() {
NMD->addOperand(MD);
}
- // Record mregparm value now so it is visible through rest of codegen.
- if (Context.getTargetInfo().getTriple().getArch() == llvm::Triple::x86)
- getModule().addModuleFlag(llvm::Module::Error, "NumRegisterParameters",
- CodeGenOpts.NumRegisterParameters);
-
if (CodeGenOpts.DwarfVersion) {
getModule().addModuleFlag(llvm::Module::Max, "Dwarf Version",
CodeGenOpts.DwarfVersion);
@@ -4781,6 +4782,7 @@ CodeGenModule::CreateRuntimeFunction(llvm::FunctionType
*FTy, StringRef Name,
}
}
setDSOLocal(F);
+ markRegisterParameterAttributes(F);
}
}
diff --git a/llvm/include/llvm/Transforms/Utils/BuildLibCalls.h
b/llvm/include/llvm/Transforms/Utils/BuildLibCalls.h
index 9ebb9500777421..a0f2f43e287c71 100644
--- a/llvm/include/llvm/Transforms/Utils/BuildLibCalls.h
+++ b/llvm/include/llvm/Transforms/Utils/BuildLibCalls.h
@@ -62,6 +62,9 @@ namespace llvm {
LibFunc TheLibFunc, AttributeList AttributeList,
FunctionType *Invalid, ArgsTy... Args) = delete;
+ // Handle -mregparm for the given function.
+ void markRegisterParameterAttributes(Function *F);
+
/// Check whether the library function is available on target and also that
/// it in the current Module is a Function with the right type.
bool isLibFuncEmittable(const Module *M, const TargetLibraryInfo *TLI,
diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
index ed0ed345435c45..e97506b4bbd95d 100644
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -1255,7 +1255,7 @@ static void setRetExtAttr(Function &F,
}
// Modeled after X86TargetLowering::markLibCallAttributes.
-static void markRegisterParameterAttributes(Function *F) {
+void llvm::markRegisterParameterAttributes(Function *F) {
if (!F->arg_size() || F->isVarArg())
return;
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