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.

Link: https://github.com/ClangBuiltLinux/linux/issues/1354
Reviewed By: pcc

Differential Revision: https://reviews.llvm.org/D104058

diff --git a/llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp b/llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp
index 37329b4..255b1f7 100644 (file)
--- a/llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp
+++ b/llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp
@@ -69,6 +69,15 @@ 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, Name, F, &ExportM);
+      appendToCompilerUsed(ExportM, A);
+    }
   }
 
   if (!RenamedComdats.empty())

diff --git a/llvm/test/Transforms/ThinLTOBitcodeWriter/cfi-icall-static-inline-asm.ll b/llvm/test/Transforms/ThinLTOBitcodeWriter/cfi-icall-static-inline-asm.ll
new file mode 100644 (file)
index 0000000..70f5322
--- /dev/null
+++ b/llvm/test/Transforms/ThinLTOBitcodeWriter/cfi-icall-static-inline-asm.ll
@@ -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"}