From 252c120f4a4c8f0fb8999c2d55bf885eef74ddca Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed.bougacha@gmail.com>
Date: Wed, 1 Apr 2015 00:45:09 +0000
Subject: [PATCH] [SimplifyLibCalls] Ignore nobuiltin/unavailable fortified
libcalls.
We used to do this before refactorings around r225640.
Some clang users checked for _chk libcall availability using:
__has_builtin(__builtin___memcpy_chk)
When compiling with -fno-builtin, this is always true.
When passing -ffreestanding/-mkernel, which both imply -fno-builtin, we
end up with fortified libcalls, which isn't acceptable in a freestanding
environment which only provides their non-fortified counterparts.
Until we change clang and/or teach external users to check for availability
differently, disregard the "nobuiltin" attribute and TLI::has.
Workaround for PR23093.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233776 91177308-0d34-0410-b5e6-96231b3b80d8
---
lib/Transforms/Utils/SimplifyLibCalls.cpp | 16 +++++++++++++---
.../X86/memset_chk-simplify-nobuiltin.ll | 18 ++++++++++++++++++
2 files changed, 31 insertions(+), 3 deletions(-)
create mode 100644 test/Transforms/CodeGenPrepare/X86/memset_chk-simplify-nobuiltin.ll
diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 339d3a326d6..00c5f040020 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -2322,8 +2322,18 @@ Value *FortifiedLibCallSimplifier::optimizeStrpNCpyChk(CallInst *CI,
}
Value *FortifiedLibCallSimplifier::optimizeCall(CallInst *CI) {
- if (CI->isNoBuiltin())
- return nullptr;
+ // FIXME: We shouldn't be changing "nobuiltin" or TLI unavailable calls here.
+ // Some clang users checked for _chk libcall availability using:
+ // __has_builtin(__builtin___memcpy_chk)
+ // When compiling with -fno-builtin, this is always true.
+ // When passing -ffreestanding/-mkernel, which both imply -fno-builtin, we
+ // end up with fortified libcalls, which isn't acceptable in a freestanding
+ // environment which only provides their non-fortified counterparts.
+ //
+ // Until we change clang and/or teach external users to check for availability
+ // differently, disregard the "nobuiltin" attribute and TLI::has.
+ //
+ // PR23093.
LibFunc::Func Func;
Function *Callee = CI->getCalledFunction();
@@ -2332,7 +2342,7 @@ Value *FortifiedLibCallSimplifier::optimizeCall(CallInst *CI) {
bool isCallingConvC = CI->getCallingConv() == llvm::CallingConv::C;
// First, check that this is a known library functions.
- if (!TLI->getLibFunc(FuncName, Func) || !TLI->has(Func))
+ if (!TLI->getLibFunc(FuncName, Func))
return nullptr;
// We never change the calling convention.
diff --git a/test/Transforms/CodeGenPrepare/X86/memset_chk-simplify-nobuiltin.ll b/test/Transforms/CodeGenPrepare/X86/memset_chk-simplify-nobuiltin.ll
new file mode 100644
index 00000000000..1e12c0192a9
--- /dev/null
+++ b/test/Transforms/CodeGenPrepare/X86/memset_chk-simplify-nobuiltin.ll
@@ -0,0 +1,18 @@
+; RUN: opt -S -disable-simplify-libcalls -codegenprepare < %s | FileCheck %s
+target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
+
+; This is a workaround for PR23093: when building with -mkernel/-fno-builtin,
+; we still generate fortified library calls.
+
+; Check that we ignore two things:
+; - attribute nobuiltin
+; - TLI::has (always returns false thanks to -disable-simplify-libcalls)
+
+; CHECK-NOT: _chk
+; CHECK: call void @llvm.memset.p0i8.i64(i8* %dst, i8 0, i64 %len, i32 1, i1 false)
+define void @test_nobuiltin(i8* %dst, i64 %len) {
+ call i8* @__memset_chk(i8* %dst, i32 0, i64 %len, i64 -1) nobuiltin
+ ret void
+}
+
+declare i8* @__memset_chk(i8*, i32, i64, i64)
--
2.34.1