[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.

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.cpp b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
index eef23a0..c977ff9 100644
--- a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
+++ b/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;