SymbolRewriter: allow rewriting with comdats

COMDATs must be identically named to the symbol.  When support for COMDATs was
introduced, the symbol rewriter was not updated, resulting in rewriting failing
for symbols which were placed into COMDATs.  This corrects the behaviour and
adds test cases for this.

llvm-svn: 227261

llvm/lib/Transforms/Utils/SymbolRewriter.cpp

@@ -79,6 +79,19 @@ static cl::list<std::string> RewriteMapFiles("rewrite-map-file",
 
 namespace llvm {
 namespace SymbolRewriter {
+void rewriteComdat(Module &M, GlobalObject *GO, const std::string &Source,
+                   const std::string &Target) {
+  if (Comdat *CD = GO->getComdat()) {
+    auto &Comdats = M.getComdatSymbolTable();
+
+    Comdat *C = M.getOrInsertComdat(Target);
+    C->setSelectionKind(CD->getSelectionKind());
+    GO->setComdat(C);
+
+    Comdats.erase(Comdats.find(Source));
+  }
+}
+
 template <RewriteDescriptor::Type DT, typename ValueType,
           ValueType *(llvm::Module::*Get)(StringRef) const>
 class ExplicitRewriteDescriptor : public RewriteDescriptor {
@@ -102,10 +115,14 @@ template <RewriteDescriptor::Type DT, typename ValueType,
 bool ExplicitRewriteDescriptor<DT, ValueType, Get>::performOnModule(Module &M) {
   bool Changed = false;
   if (ValueType *S = (M.*Get)(Source)) {
+    if (GlobalObject *GO = dyn_cast<GlobalObject>(S))
+      rewriteComdat(M, GO, Source, Target);
+
     if (Value *T = (M.*Get)(Target))
       S->setValueName(T->getValueName());
     else
       S->setName(Target);
+
     Changed = true;
   }
   return Changed;
@@ -148,6 +165,9 @@ performOnModule(Module &M) {
     if (C.getName() == Name)
       continue;
 
+    if (GlobalObject *GO = dyn_cast<GlobalObject>(&C))
+      rewriteComdat(M, GO, C.getName(), Name);
+
     if (Value *V = (M.*Get)(Name))
       C.setValueName(V->getValueName());
     else

llvm/test/SymbolRewriter/rewrite.ll

@@ -28,12 +28,40 @@ entry:
   ret void
 }
 
+$source_comdat_function = comdat any
+define dllexport void @source_comdat_function() comdat($source_comdat_function) {
+entry:
+  ret void
+}
+
+$source_comdat_function_1 = comdat exactmatch
+define dllexport void @source_comdat_function_1() comdat($source_comdat_function_1) {
+entry:
+  ret void
+}
+
+$source_comdat_variable = comdat largest
+@source_comdat_variable = global i32 32, comdat($source_comdat_variable)
+
+$source_comdat_variable_1 = comdat noduplicates
+@source_comdat_variable_1 = global i32 64, comdat($source_comdat_variable_1)
+
+; CHECK: $target_comdat_function = comdat any
+; CHECK: $target_comdat_function_1 = comdat exactmatch
+; CHECK: $target_comdat_variable = comdat largest
+; CHECK: $target_comdat_variable_1 = comdat noduplicates
+
 ; CHECK: @target_variable = external global i32
 ; CHECK-NOT: @source_variable = external global i32
 ; CHECK: @target_pattern_variable = external global i32
 ; CHECK-NOT: @source_pattern_variable = external global i32
 ; CHECK: @target_pattern_multiple_variable_matches = external global i32
 ; CHECK-NOT: @source_pattern_multiple_variable_matches = external global i32
+; CHECK: @target_comdat_variable = global i32 32, comdat
+; CHECK-NOT: @source_comdat_variable = global i32 32, comdat
+; CHECK: @target_comdat_variable_1 = global i32 64, comdat
+; CHECK-NOT: @source_comdat_variable_1 = global i32 64, comdat
+
 ; CHECK: declare void @target_function()
 ; CHECK-NOT: declare void @source_function()
 ; CHECK: declare void @target_pattern_function()
@@ -57,3 +85,8 @@ entry:
 ; CHECK:   ret i32 %res
 ; CHECK: }
 
+; CHECK: define dllexport void @target_comdat_function() comdat
+; CHECK-NOT: define dllexport void @source_comdat_function() comdat
+; CHECK: define dllexport void @target_comdat_function_1() comdat
+; CHECK-NOT: define dllexport void @source_comdat_function_1() comdat
+

llvm/test/SymbolRewriter/rewrite.map

@@ -44,3 +44,23 @@ global alias: {
   target: _ZN1SD1Ev,
 }
 
+function: {
+  source: source_comdat_function,
+  target: target_comdat_function,
+}
+
+function: {
+  source: source_comdat_function_(.*),
+  transform: target_comdat_function_\1,
+}
+
+global variable: {
+  source: source_comdat_variable,
+  target: target_comdat_variable,
+}
+
+global variable: {
+  source: source_comdat_variable_(.*),
+  transform: target_comdat_variable_\1,
+}
+