Explicitly initialize opaque pointer mode in CodeGenAction

[MatzeB]

Summary

Explicitly call LLVMContext::setOpaquePointers in CodeGenAction before loading any IR files. With this we use the mode specified on the command-line rather than lazily initializing it based on the contents of the IR.

This helps when using -fthinlto-index which may end up mixing files with typed and opaque pointer types which fails when the first file happened to use typed pointers since we cannot downgrade IR with opaque pointer types to typed pointer types.

[nikic]

clang/lib/CodeGen/CodeGenAction.cpp

1138

I think it would be fine to always do this, not just for the ThinLTO case.

clang/test/CodeGen/thinlto-opaque-typed-mix.ll

15

What's the false doing here?

[MatzeB]

address review feedback.

[nikic]

LG

clang/lib/CodeGen/CodeGenAction.cpp

CodeGenAction::CreateASTConsumer(CompilerInstance &CI, StringRef InFile) {
   return std::move(Result);
 }
 
 std::unique_ptr<llvm::Module>
 CodeGenAction::loadModule(MemoryBufferRef MBRef) {
   CompilerInstance &CI = getCompilerInstance();
   SourceManager &SM = CI.getSourceManager();
 
+  VMContext->setOpaquePointers(CI.getCodeGenOpts().OpaquePointers);
+
   // For ThinLTO backend invocations, ensure that the context
   // merges types based on ODR identifiers. We also need to read
   // the correct module out of a multi-module bitcode file.
   if (!CI.getCodeGenOpts().ThinLTOIndexFile.empty()) {
     VMContext->enableDebugTypeODRUniquing();
 
     auto DiagErrors = [&](Error E) -> std::unique_ptr<llvm::Module> {
       unsigned DiagID =
if (!CI.getCodeGenOpts().ThinLTOIndexFile.empty()) {
     if (!Bm) {
       auto M = std::make_unique<llvm::Module>("empty", *VMContext);
       M->setTargetTriple(CI.getTargetOpts().Triple);
       return M;
     }
     Expected<std::unique_ptr<llvm::Module>> MOrErr =
         Bm->parseModule(*VMContext);
     if (!MOrErr)
       return DiagErrors(MOrErr.takeError());
     return std::move(*MOrErr);
   }
 
   llvm::SMDiagnostic Err;
   if (std::unique_ptr<llvm::Module> M = parseIR(MBRef, Err, *VMContext))
     return M;
 
   // Translate from the diagnostic info to the SourceManager location if

clang/test/CodeGen/Inputs/thinlto-opaque.ll

+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64--"
+
+define ptr @f2() {
+  ret ptr null
+}

clang/test/CodeGen/thinlto-distributed-cfi-devirt.ll

cont2:
   %7 = extractvalue { i8*, i1 } %5, 0
   %8 = bitcast i8* %7 to i32 (%struct.A*, i32)*
 
   ; Check that traps are conditional. Invalid TYPE_ID can cause
   ; unconditional traps.
   ; CHECK-IR: br i1 {{.*}}, label %trap
 
   ; We still have to call it as virtual.
-  ; CHECK-IR: %call3 = tail call i32 %7
+  ; CHECK-IR: %call3 = tail call i32 {{%[0-9]+}}
   %call3 = tail call i32 %8(%struct.A* nonnull %obj, i32 %call)
   ret i32 %call3
 }
 ; CHECK-IR-LABEL: ret i32
 ; CHECK-IR-LABEL: }
 
 declare { i8*, i1 } @llvm.type.checked.load(i8*, i32, metadata)
 declare void @llvm.trap()
 
 declare i32 @_ZN1B1fEi(%struct.B* %this, i32 %a)
 declare i32 @_ZN1A1nEi(%struct.A* %this, i32 %a)
 declare i32 @_ZN1C1fEi(%struct.C* %this, i32 %a)
 
 !0 = !{i64 16, !"_ZTS1A"}
 !1 = !{i64 16, !"_ZTS1B"}
 !2 = !{i64 16, !"_ZTS1C"}

clang/test/CodeGen/thinlto-opaque-typed-mix.ll

+; REQUIRES: x86-registered-target
+; Test that mixing bitcode file with opaque and typed pointers works.
+
+; RUN: mkdir -p %t
+; RUN: opt -module-summary -o %t/typed.bc %s
+; RUN: opt -module-summary -o %t/opaque.bc %S/Inputs/thinlto-opaque.ll
+; RUN: llvm-lto2 run -thinlto-distributed-indexes %t/typed.bc %t/opaque.bc \
+; RUN:   -o %t/native.o -r %t/typed.bc,main,plx -r %t/typed.bc,f2, \
+; RUN:   -r %t/opaque.bc,f2,p
+
+; RUN: %clang_cc1 -triple x86_64-- -emit-obj -o %t/native.o %t/typed.bc \
+; RUN:   -Wno-override-module \
+; RUN:   -fthinlto-index=%t/typed.bc.thinlto.bc
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64--"
+
+declare i8* @f2()
+
+define i32 @main() {
+  call i8* @f2()
+  ret i32 0
+}