[CIR] Set the module name to the input filename (#160934)

This sets the MLIR module name to the main filename (according to the
SourceManager), if one is available. The module name gets used when
creating global init functions, so we will need it to be set.

Author: andykaylor

clang/lib/CIR/CodeGen/CIRGenModule.cpp

@@ -119,6 +119,19 @@ CIRGenModule::CIRGenModule(mlir::MLIRContext &mlirContext,
                        cir::OptInfoAttr::get(&mlirContext,
                                              cgo.OptimizationLevel,
                                              cgo.OptimizeSize));
+  // Set the module name to be the name of the main file. TranslationUnitDecl
+  // often contains invalid source locations and isn't a reliable source for the
+  // module location.
+  FileID mainFileId = astContext.getSourceManager().getMainFileID();
+  const FileEntry &mainFile =
+      *astContext.getSourceManager().getFileEntryForID(mainFileId);
+  StringRef path = mainFile.tryGetRealPathName();
+  if (!path.empty()) {
+    theModule.setSymName(path);
+    theModule->setLoc(mlir::FileLineColLoc::get(&mlirContext, path,
+                                                /*line=*/0,
+                                                /*column=*/0));
+  }
 }
 
 CIRGenModule::~CIRGenModule() = default;

clang/test/CIR/CodeGen/lang-c-cpp.cpp

@@ -3,8 +3,8 @@
 // RUN: %clang_cc1 -x c -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.c.cir
 // RUN: FileCheck --check-prefix=CIR-C --input-file=%t.c.cir %s
 
-// CIR-CPP: module attributes {{{.*}}cir.lang = #cir.lang<cxx>{{.*}}}
-// CIR-C: module attributes {{{.*}}cir.lang = #cir.lang<c>{{.*}}}
+// CIR-CPP: module{{.*}} attributes {{{.*}}cir.lang = #cir.lang<cxx>{{.*}}}
+// CIR-C: module{{.*}} attributes {{{.*}}cir.lang = #cir.lang<c>{{.*}}}
 
 int main() {
   return 0;

clang/test/CIR/CodeGen/module-filename.cpp

@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+
+// Normally, we try to avoid checking the filename of a test, but that's the
+// entire point of this test, so we use a wildcard for the path but check the
+// filename.
+// CIR: module @"{{.*}}module-filename.cpp"
+
+int main() {
+  return 0;
+}

clang/test/CIR/CodeGen/opt-info-attr.cpp

@@ -13,10 +13,10 @@
 
 void f() {}
 
-// CHECK-O0: module attributes
+// CHECK-O0: module{{.*}} attributes
 // CHECK-O0-NOT: cir.opt_info
-// CHECK-O1: module attributes {{.+}}cir.opt_info = #cir.opt_info<level = 1, size = 0>{{.+}}
-// CHECK-O2: module attributes {{.+}}cir.opt_info = #cir.opt_info<level = 2, size = 0>{{.+}}
-// CHECK-O3: module attributes {{.+}}cir.opt_info = #cir.opt_info<level = 3, size = 0>{{.+}}
-// CHECK-Os: module attributes {{.+}}cir.opt_info = #cir.opt_info<level = 2, size = 1>{{.+}}
-// CHECK-Oz: module attributes {{.+}}cir.opt_info = #cir.opt_info<level = 2, size = 2>{{.+}}
+// CHECK-O1: module{{.*}} attributes {{.+}}cir.opt_info = #cir.opt_info<level = 1, size = 0>{{.+}}
+// CHECK-O2: module{{.*}} attributes {{.+}}cir.opt_info = #cir.opt_info<level = 2, size = 0>{{.+}}
+// CHECK-O3: module{{.*}} attributes {{.+}}cir.opt_info = #cir.opt_info<level = 3, size = 0>{{.+}}
+// CHECK-Os: module{{.*}} attributes {{.+}}cir.opt_info = #cir.opt_info<level = 2, size = 1>{{.+}}
+// CHECK-Oz: module{{.*}} attributes {{.+}}cir.opt_info = #cir.opt_info<level = 2, size = 2>{{.+}}