The wrong placement of add pass with optimizations led to -funique-internal-linkage-names being disabled.

Fixed the placement of the MPM.addpass for UniqueInternalLinkageNames to make
it work correctly with -O2 and new pass manager. Updated the tests to
explicitly check O0 and O2.

Previously, the addPass was placed before BackendUtil.cpp#L1373 which is wrong
as MPM gets assigned at this point and any additions to the pass vector before
this is wrong. This change just moves it after MPM is assigned and places it at
a point where O0 and O0+ can share it.

Differential Revision: https://reviews.llvm.org/D87921

Author: tmsri

clang/lib/CodeGen/BackendUtil.cpp

@@ -1262,12 +1262,6 @@ void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
       if (LangOpts.Sanitize.has(SanitizerKind::LocalBounds))
         MPM.addPass(createModuleToFunctionPassAdaptor(BoundsCheckingPass()));
 
-      // Add UniqueInternalLinkageNames Pass which renames internal linkage
-      // symbols with unique names.
-      if (CodeGenOpts.UniqueInternalLinkageNames) {
-        MPM.addPass(UniqueInternalLinkageNamesPass());
-      }
-
       // Lastly, add semantically necessary passes for LTO.
       if (IsLTO || IsThinLTO) {
         MPM.addPass(CanonicalizeAliasesPass());
@@ -1363,12 +1357,6 @@ void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
           MPM.addPass(InstrProfiling(*Options, false));
         });
 
-      // Add UniqueInternalLinkageNames Pass which renames internal linkage
-      // symbols with unique names.
-      if (CodeGenOpts.UniqueInternalLinkageNames) {
-        MPM.addPass(UniqueInternalLinkageNamesPass());
-      }
-
       if (IsThinLTO) {
         MPM = PB.buildThinLTOPreLinkDefaultPipeline(
             Level, CodeGenOpts.DebugPassManager);
@@ -1385,6 +1373,11 @@ void EmitAssemblyHelper::EmitAssemblyWithNewPassManager(
       }
     }
 
+    // Add UniqueInternalLinkageNames Pass which renames internal linkage
+    // symbols with unique names.
+    if (CodeGenOpts.UniqueInternalLinkageNames)
+      MPM.addPass(UniqueInternalLinkageNamesPass());
+
     if (CodeGenOpts.MemProf) {
       MPM.addPass(createModuleToFunctionPassAdaptor(MemProfilerPass()));
       MPM.addPass(ModuleMemProfilerPass());

clang/test/CodeGen/unique-internal-linkage-names.cpp

@@ -1,8 +1,10 @@
 // This test checks if internal linkage symbols get unique names with
 // -funique-internal-linkage-names option.
 // RUN: %clang_cc1 -triple x86_64 -x c++ -S -emit-llvm -o - < %s | FileCheck %s --check-prefix=PLAIN
-// RUN: %clang_cc1 -triple x86_64 -x c++ -S -emit-llvm -funique-internal-linkage-names -o - < %s | FileCheck %s --check-prefix=UNIQUE
-// RUN: %clang_cc1 -triple x86_64 -x c++ -S -emit-llvm -fexperimental-new-pass-manager -funique-internal-linkage-names -o - < %s | FileCheck %s --check-prefix=UNIQUE
+// RUN: %clang_cc1 -triple x86_64 -x c++ -O0 -S -emit-llvm -funique-internal-linkage-names -o - < %s | FileCheck %s --check-prefix=UNIQUE
+// RUN: %clang_cc1 -triple x86_64 -x c++ -O1 -S -emit-llvm -funique-internal-linkage-names -o - < %s | FileCheck %s --check-prefix=UNIQUEO1
+// RUN: %clang_cc1 -triple x86_64 -x c++ -O0 -S -emit-llvm -fexperimental-new-pass-manager -funique-internal-linkage-names -o - < %s | FileCheck %s --check-prefix=UNIQUE
+// RUN: %clang_cc1 -triple x86_64 -x c++ -O1 -S -emit-llvm -fexperimental-new-pass-manager -funique-internal-linkage-names -o - < %s | FileCheck %s --check-prefix=UNIQUEO1
 
 static int glob;
 static int foo() {
@@ -59,3 +61,7 @@ int mver_call() {
 // UNIQUE: define weak_odr i32 ()* @_ZL4mverv.resolver()
 // UNIQUE: define internal i32 @_ZL4mverv.{{[0-9a-f]+}}()
 // UNIQUE: define internal i32 @_ZL4mverv.sse4.2.{{[0-9a-f]+}}
+// UNIQUEO1: define internal i32 @_ZL3foov.{{[0-9a-f]+}}()
+// UNIQUEO1: define weak_odr i32 ()* @_ZL4mverv.resolver()
+// UNIQUEO1: define internal i32 @_ZL4mverv.{{[0-9a-f]+}}()
+// UNIQUEO1: define internal i32 @_ZL4mverv.sse4.2.{{[0-9a-f]+}}