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ThinLTO: Fix inline assembly references to static functions with CFI 

Create an internal alias with the original name for static functions
that are renamed in promoteInternals to avoid breaking inline
assembly references to them.

This relands commit 4474958d3a
with a fix to a use-of-uninitialized-value error that tripped
MemorySanitizer.

Link: https://github.com/ClangBuiltLinux/linux/issues/1354

Reviewed By: nickdesaulniers, pcc

Differential Revision: https://reviews.llvm.org/D104058
This commit is contained in:
Sami Tolvanen 2021-06-23 10:09:21 -07:00
parent ec08f03be3
commit e3d24b45b8
2 changed files with 29 additions and 0 deletions
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10
llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp
View File

@ -55,6 +55,7 @@ void promoteInternals(Module &ExportM, Module &ImportM, StringRef ModuleId,
}
}
std::string OldName = Name.str();
std::string NewName = (Name + ModuleId).str();
if (const auto *C = ExportGV.getComdat())
@ -69,6 +70,15 @@ void promoteInternals(Module &ExportM, Module &ImportM, StringRef ModuleId,
ImportGV->setName(NewName);
ImportGV->setVisibility(GlobalValue::HiddenVisibility);
}
if (Function *F = dyn_cast<Function>(&ExportGV)) {
// Create a local alias with the original name to avoid breaking
// references from inline assembly.
GlobalAlias *A = GlobalAlias::create(
F->getValueType(), F->getAddressSpace(), GlobalValue::InternalLinkage,
OldName, F, &ExportM);
appendToCompilerUsed(ExportM, A);
}
}
if (!RenamedComdats.empty())

19
llvm/test/Transforms/ThinLTOBitcodeWriter/cfi-icall-static-inline-asm.ll Normal file
View File

@ -0,0 +1,19 @@
; RUN: opt -thinlto-bc -thinlto-split-lto-unit -o - %s | llvm-modextract -b -n 0 -o - | llvm-dis | FileCheck %s
; CHECK: @a = internal alias {{.*}}@a.[[HASH:[0-9a-f]+]]
define void @b() {
%f = alloca void ()*, align 8
; CHECK: store{{.*}} @a.[[HASH]],{{.*}} %f
store void ()* @a, void ()** %f, align 8
; CHECK: %1 = call void ()* asm sideeffect "leaq a(%rip)
%1 = call void ()* asm sideeffect "leaq a(%rip), $0\0A\09", "=r,~{dirflag},~{fpsr},~{flags}"()
ret void
}
; CHECK: define{{.*}} @a.[[HASH]](){{.*}} !type
define internal void @a() !type !0 {
ret void
}
!0 = !{i64 0, !"typeid1"}