[clang] 5c5bbff - [clang][ASTImporter] Import source location of explicit object parameter instead of copying it (#124305)

[via cfe-commits]

Author: Michael Buch
Date: 2025-01-27T14:57:09Z
New Revision: 5c5bbffe75caaaefdc68305e85a625a057b09159

URL: https://github.com/llvm/llvm-project/commit/5c5bbffe75caaaefdc68305e85a625a057b09159
DIFF: https://github.com/llvm/llvm-project/commit/5c5bbffe75caaaefdc68305e85a625a057b09159.diff

LOG: [clang][ASTImporter] Import source location of explicit object parameter instead of copying it (#124305)

We used to copy the `SourceLocation` instead of importing it, which
isn't correct since the `SourceManager`'s of the source and target
ASTContext might differ.

Also adds test that confirms that we import the explicit object
parameter location for `ParmVarDecl`s. This is how Clang determines
whether a parameter `isExplicitObjectParamater`. The LLDB expression
evaluator relies on this for calling "explicit object member functions".

Added: 
    

Modified: 
    clang/lib/AST/ASTImporter.cpp
    clang/unittests/AST/ASTImporterTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index 0669aa1b809c34..be1a65a49622d3 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -4701,9 +4701,13 @@ ExpectedDecl ASTNodeImporter::VisitImplicitParamDecl(ImplicitParamDecl *D) {
 
 Error ASTNodeImporter::ImportDefaultArgOfParmVarDecl(
     const ParmVarDecl *FromParam, ParmVarDecl *ToParam) {
+
+  if (auto LocOrErr = import(FromParam->getExplicitObjectParamThisLoc()))
+    ToParam->setExplicitObjectParameterLoc(*LocOrErr);
+  else
+    return LocOrErr.takeError();
+
   ToParam->setHasInheritedDefaultArg(FromParam->hasInheritedDefaultArg());
-  ToParam->setExplicitObjectParameterLoc(
-      FromParam->getExplicitObjectParamThisLoc());
   ToParam->setKNRPromoted(FromParam->isKNRPromoted());
 
   if (FromParam->hasUninstantiatedDefaultArg()) {

diff  --git a/clang/unittests/AST/ASTImporterTest.cpp b/clang/unittests/AST/ASTImporterTest.cpp
index 791248e7a394f1..e77860521335ed 100644
--- a/clang/unittests/AST/ASTImporterTest.cpp
+++ b/clang/unittests/AST/ASTImporterTest.cpp
@@ -3441,6 +3441,7 @@ TEST_P(ASTImporterOptionSpecificTestBase, ImportParmVarDecl) {
   ASSERT_TRUE(FromVar);
   ASSERT_TRUE(FromVar->hasUninstantiatedDefaultArg());
   ASSERT_TRUE(FromVar->getUninstantiatedDefaultArg());
+  ASSERT_FALSE(FromVar->isExplicitObjectParameter());
 
   const auto *ToVar = Import(FromVar, Lang_CXX11);
   EXPECT_TRUE(ToVar);
@@ -3448,6 +3449,25 @@ TEST_P(ASTImporterOptionSpecificTestBase, ImportParmVarDecl) {
   EXPECT_TRUE(ToVar->getUninstantiatedDefaultArg());
   EXPECT_NE(FromVar->getUninstantiatedDefaultArg(),
             ToVar->getUninstantiatedDefaultArg());
+  EXPECT_FALSE(ToVar->isExplicitObjectParameter());
+}
+
+TEST_P(ASTImporterOptionSpecificTestBase, ImportParmVarDecl_Explicit) {
+  const auto *Code = R"(
+    struct Wrapper {
+      void func(this Wrapper) {}
+    };
+    )";
+  Decl *FromTU = getTuDecl(Code, Lang_CXX23);
+  auto *FromVar = FirstDeclMatcher<ParmVarDecl>().match(FromTU, parmVarDecl());
+  ASSERT_TRUE(FromVar);
+  ASSERT_TRUE(FromVar->isExplicitObjectParameter());
+
+  const auto *ToVar = Import(FromVar, Lang_CXX23);
+  EXPECT_TRUE(ToVar);
+  EXPECT_TRUE(ToVar->isExplicitObjectParameter());
+  EXPECT_NE(ToVar->getExplicitObjectParamThisLoc(),
+            FromVar->getExplicitObjectParamThisLoc());
 }
 
 TEST_P(ASTImporterOptionSpecificTestBase, ImportOfNonEquivalentField) {