[CIR] add support for file scope assembly (#152093)

This PR adds a support for file scope assembly in CIR.

Author: gitoleg

clang/include/clang/CIR/Dialect/IR/CIRDialect.td

@@ -40,6 +40,7 @@ def CIR_Dialect : Dialect {
     static llvm::StringRef getCalleeAttrName() { return "callee"; }
     static llvm::StringRef getNoThrowAttrName() { return "nothrow"; }
     static llvm::StringRef getSideEffectAttrName() { return "side_effect"; }
+    static llvm::StringRef getModuleLevelAsmAttrName() { return "cir.module_asm"; }
 
     void registerAttributes();
     void registerTypes();

clang/lib/CIR/CodeGen/CIRGenModule.cpp

@@ -1365,6 +1365,21 @@ void CIRGenModule::emitTopLevelDecl(Decl *decl) {
     assert(!cir::MissingFeatures::generateDebugInfo());
     assert(!cir::MissingFeatures::cxxRecordStaticMembers());
     break;
+
+  case Decl::FileScopeAsm:
+    // File-scope asm is ignored during device-side CUDA compilation.
+    if (langOpts.CUDA && langOpts.CUDAIsDevice)
+      break;
+    // File-scope asm is ignored during device-side OpenMP compilation.
+    if (langOpts.OpenMPIsTargetDevice)
+      break;
+    // File-scope asm is ignored during device-side SYCL compilation.
+    if (langOpts.SYCLIsDevice)
+      break;
+    auto *file_asm = cast<FileScopeAsmDecl>(decl);
+    std::string line = file_asm->getAsmString();
+    globalScopeAsm.push_back(builder.getStringAttr(line));
+    break;
   }
 }
 
@@ -1978,6 +1993,9 @@ void CIRGenModule::release() {
   emitDeferred();
   applyReplacements();
 
+  theModule->setAttr(cir::CIRDialect::getModuleLevelAsmAttrName(),
+                     builder.getArrayAttr(globalScopeAsm));
+
   // There's a lot of code that is not implemented yet.
   assert(!cir::MissingFeatures::cgmRelease());
 }

clang/lib/CIR/CodeGen/CIRGenModule.h

@@ -90,6 +90,8 @@ class CIRGenModule : public CIRGenTypeCache {
   /// for FunctionDecls's.
   CIRGenFunction *curCGF = nullptr;
 
+  llvm::SmallVector<mlir::Attribute> globalScopeAsm;
+
 public:
   mlir::ModuleOp getModule() const { return theModule; }
   CIRGenBuilderTy &getBuilder() { return builder; }

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

@@ -2143,6 +2143,11 @@ void ConvertCIRToLLVMPass::processCIRAttrs(mlir::ModuleOp module) {
           module->getAttr(cir::CIRDialect::getTripleAttrName()))
     module->setAttr(mlir::LLVM::LLVMDialect::getTargetTripleAttrName(),
                     tripleAttr);
+
+  if (mlir::Attribute asmAttr =
+          module->getAttr(cir::CIRDialect::getModuleLevelAsmAttrName()))
+    module->setAttr(mlir::LLVM::LLVMDialect::getModuleLevelAsmAttrName(),
+                    asmAttr);
 }
 
 void ConvertCIRToLLVMPass::runOnOperation() {

clang/test/CIR/CodeGen/module-asm.c

@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-cir %s -o %t.cir 
+// RUN: FileCheck --input-file=%t.cir %s
+
+// CHECK:  cir.module_asm = [".globl bar", ".globl foo"]
+__asm (".globl bar");
+__asm (".globl foo");

clang/test/CIR/Lowering/module-asm.cir

@@ -0,0 +1,11 @@
+// RUN: cir-opt %s -cir-to-llvm -o %t.cir
+// RUN: FileCheck %s --input-file=%t.cir
+
+// RUN: cir-translate -cir-to-llvmir --disable-cc-lowering -o %t.ll %s
+// RUN: FileCheck -check-prefix=LLVM --input-file=%t.ll %s
+
+// CHECK: llvm.module_asm =  [".globl bar", ".globl foo"]
+// LLVM: module asm ".globl bar"
+// LLVM: module asm ".globl foo"
+module attributes {cir.module_asm = [".globl bar", ".globl foo"]} {
+}