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 version uses module inline assembly
to avoid issues with LowerTypeTestsModule.

Link: ClangBuiltLinux/linux#1354

Reviewed By: nickdesaulniers, pcc

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

Author: samitolvanen

llvm/lib/Transforms/IPO/ThinLTOBitcodeWriter.cpp

@@ -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 +70,13 @@ 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.
+      std::string Alias = ".set " + OldName + "," + NewName + "\n";
+      ExportM.appendModuleInlineAsm(Alias);
+    }
   }
 
   if (!RenamedComdats.empty())

llvm/test/ThinLTO/X86/devirt2.ll

@@ -131,10 +131,12 @@
 ; RUN:   -r=%t1.o,_ZN1D1mEi, \
 ; RUN:   -r=%t1.o,test2, \
 ; RUN:   -r=%t2.o,_ZN1A1nEi,p \
+; RUN:   -r=%t2.o,_ZN1A1nEi, \
 ; RUN:   -r=%t2.o,_ZN1B1fEi,p \
 ; RUN:   -r=%t2.o,_ZN1C1fEi,p \
 ; RUN:   -r=%t2.o,_ZN1D1mEi,p \
 ; RUN:   -r=%t2.o,_ZN1E1mEi,p \
+; RUN:   -r=%t2.o,_ZN1E1mEi, \
 ; RUN:   -r=%t2.o,_ZTV1B, \
 ; RUN:   -r=%t2.o,_ZTV1C, \
 ; RUN:   -r=%t2.o,_ZTV1D, \
@@ -167,10 +169,12 @@
 ; RUN:   -r=%t1.o,_ZN1D1mEi, \
 ; RUN:   -r=%t1.o,test2, \
 ; RUN:   -r=%t2.o,_ZN1A1nEi,p \
+; RUN:   -r=%t2.o,_ZN1A1nEi, \
 ; RUN:   -r=%t2.o,_ZN1B1fEi,p \
 ; RUN:   -r=%t2.o,_ZN1C1fEi,p \
 ; RUN:   -r=%t2.o,_ZN1D1mEi,p \
 ; RUN:   -r=%t2.o,_ZN1E1mEi,p \
+; RUN:   -r=%t2.o,_ZN1E1mEi, \
 ; RUN:   -r=%t2.o,_ZTV1B, \
 ; RUN:   -r=%t2.o,_ZTV1C, \
 ; RUN:   -r=%t2.o,_ZTV1D, \

llvm/test/Transforms/ThinLTOBitcodeWriter/cfi-icall-static-inline-asm.ll

@@ -0,0 +1,21 @@
+; RUN: opt -thinlto-bc -thinlto-split-lto-unit -o - %s | llvm-modextract -b -n 0 -o - | llvm-dis | FileCheck %s
+
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK: module asm ".set a,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"}

llvm/test/Transforms/ThinLTOBitcodeWriter/split-internal2.ll

@@ -7,6 +7,8 @@
 ; RUN: llvm-bcanalyzer -dump %t0 | FileCheck --check-prefix=BCA0 %s
 ; RUN: llvm-bcanalyzer -dump %t1 | FileCheck --check-prefix=BCA1 %s
 
+target triple = "x86_64-unknown-linux-gnu"
+
 ; ERROR: llvm-modextract: error: module index out of range; bitcode file contains 2 module(s)
 
 ; BCA0: <GLOBALVAL_SUMMARY_BLOCK

llvm/test/Transforms/ThinLTOBitcodeWriter/split-vfunc-internal.ll

@@ -2,6 +2,8 @@
 ; RUN: llvm-modextract -b -n 0 -o - %t | llvm-dis | FileCheck --check-prefix=M0 %s
 ; RUN: llvm-modextract -b -n 1 -o - %t | llvm-dis | FileCheck --check-prefix=M1 %s
 
+target triple = "x86_64-unknown-linux-gnu"
+
 define [1 x i8*]* @source() {
   ret [1 x i8*]* @g
 }