[MLIR][LLVM] Import LLVM target triple into MLIR LLVM Dialect (llvm#125084)

It would be essential and useful info to have it in MLIR when we are
doing optimizations at MLIR level using LLVM IR as input.

Author: ghehg

mlir/include/mlir/Target/LLVMIR/ModuleImport.h

@@ -71,6 +71,10 @@ class ModuleImport {
   /// specification.
   LogicalResult convertDataLayout();
 
+  /// Converts target triple of the LLVM module to an MLIR target triple
+  /// specification.
+  void convertTargetTriple();
+
   /// Stores the mapping between an LLVM value and its MLIR counterpart.
   void mapValue(llvm::Value *llvm, Value mlir) { mapValue(llvm) = mlir; }
 

mlir/lib/Target/LLVMIR/ModuleImport.cpp

@@ -662,6 +662,11 @@ LogicalResult ModuleImport::convertDataLayout() {
   return success();
 }
 
+void ModuleImport::convertTargetTriple() {
+  mlirModule->setAttr(LLVM::LLVMDialect::getTargetTripleAttrName(),
+                      builder.getStringAttr(llvmModule->getTargetTriple()));
+}
+
 LogicalResult ModuleImport::convertFunctions() {
   for (llvm::Function &func : llvmModule->functions())
     if (failed(processFunction(&func)))
@@ -2451,6 +2456,6 @@ mlir::translateLLVMIRToModule(std::unique_ptr<llvm::Module> llvmModule,
     return {};
   if (failed(moduleImport.convertFunctions()))
     return {};
-
+  moduleImport.convertTargetTriple();
   return module;
 }

mlir/test/Target/LLVMIR/Import/target-triple.ll

@@ -0,0 +1,5 @@
+; RUN: mlir-translate -import-llvm %s | FileCheck %s
+; CHECK: module attributes {
+; CHECK-SAME: llvm.target_triple = "aarch64-none-linux-android21"
+target triple = "aarch64-none-linux-android21"
+