[clang] [Clang] Fix an inadvertent overwrite of sub-initializers (PR #140714)

2025-05-20 Thread Younan Zhang via cfe-commits 

https://github.com/zyn0217 closed 
https://github.com/llvm/llvm-project/pull/140714
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[clang] [Clang] Fix an inadvertent overwrite of sub-initializers (PR #140714)

2025-05-20 Thread via cfe-commits 

https://github.com/cor3ntin approved this pull request.

Oh gosh!

https://github.com/llvm/llvm-project/pull/140714
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[clang] [Clang] Fix an inadvertent overwrite of sub-initializers (PR #140714)

2025-05-20 Thread via cfe-commits 

llvmbot wrote:




@llvm/pr-subscribers-clang

Author: Younan Zhang (zyn0217)


Changes

When using InitChecker with VerifyOnly, we create a new designated initializer 
to handle anonymous fields. However in the last call to 
CheckDesignatedInitializer, the subinitializer isn't properly preserved but it 
gets overwritten by the cloned one. Which causes the initializer to reference 
the dependent field, breaking assumptions when we initialize the instantiated 
specialization.

Fixes https://github.com/llvm/llvm-project/issues/67173

---
Full diff: https://github.com/llvm/llvm-project/pull/140714.diff


3 Files Affected:

- (modified) clang/docs/ReleaseNotes.rst (+1) 
- (modified) clang/lib/Sema/SemaInit.cpp (+8-4) 
- (modified) clang/test/SemaTemplate/deduction-guide.cpp (+27) 


``diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index f04cb7b91788c..6f97cf79c5058 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -690,6 +690,7 @@ Bug Fixes to C++ Support
   certain differences in qualifiers (this could happen during template argument
   deduction or when building a ternary operator). (#GH97005)
 - Fixed type alias CTAD issues involving default template arguments. 
(#GH134471)
+- Fixed CTAD issues when initializing anonymous fields with designated 
initializers. (#GH67173)
 - The initialization kind of elements of structured bindings
   direct-list-initialized from an array is corrected to direct-initialization.
 - Clang no longer crashes when a coroutine is declared ``[[noreturn]]``. 
(#GH127327)
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 9ee8603ff7811..1f204f8306842 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -2791,16 +2791,20 @@ InitListChecker::CheckDesignatedInitializer(const 
InitializedEntity &Entity,
 // initializer list that the child calls see, so that we don't try
 // to re-process the designator.
 unsigned OldIndex = Index;
-IList->setInit(OldIndex, DIE->getInit());
+auto *OldDIE =
+dyn_cast_if_present(IList->getInit(OldIndex));
+if (!OldDIE)
+  OldDIE = DIE;
+IList->setInit(OldIndex, OldDIE->getInit());
 
 CheckSubElementType(Entity, IList, CurrentObjectType, Index, 
StructuredList,
 StructuredIndex, /*DirectlyDesignated=*/true);
 
 // Restore the designated initializer expression in the syntactic
 // form of the initializer list.
-if (IList->getInit(OldIndex) != DIE->getInit())
-  DIE->setInit(IList->getInit(OldIndex));
-IList->setInit(OldIndex, DIE);
+if (IList->getInit(OldIndex) != OldDIE->getInit())
+  OldDIE->setInit(IList->getInit(OldIndex));
+IList->setInit(OldIndex, OldDIE);
 
 return hadError && !prevHadError;
   }
diff --git a/clang/test/SemaTemplate/deduction-guide.cpp 
b/clang/test/SemaTemplate/deduction-guide.cpp
index dabd0cf12f77e..c1ce55e1c8029 100644
--- a/clang/test/SemaTemplate/deduction-guide.cpp
+++ b/clang/test/SemaTemplate/deduction-guide.cpp
@@ -886,3 +886,30 @@ CC c{};
 // CHECK-NEXT:`-ClassTemplateSpecialization {{.+}} 'A'
 
 }
+
+namespace GH67173 {
+
+template  struct Vec2d {
+  struct {
+T x;
+T y;
+  };
+};
+
+void f() {
+  Vec2d v{.x = 1, .y = 2};
+}
+
+// CHECK-LABEL: Dumping GH67173:::
+// CHECK-NEXT: FunctionTemplateDecl {{.+}} implicit 
+// CHECK-NEXT: |-TemplateTypeParmDecl {{.+}} referenced class depth 0 index 0 T
+// CHECK:  |-CXXDeductionGuideDecl {{.+}} implicit  'auto (T, T) -> Vec2d' aggregate
+// CHECK-NEXT: | |-ParmVarDecl {{.+}} col:27 'T'
+// CHECK-NEXT: | `-ParmVarDecl {{.+}} col:27 'T'
+// CHECK-NEXT: `-CXXDeductionGuideDecl {{.+}} implicit used  'auto (int, int) -> GH67173::Vec2d' implicit_instantiation 
aggregate
+// CHECK-NEXT:   |-TemplateArgument type 'int'
+// CHECK-NEXT:   | `-BuiltinType {{.+}} 'int'
+// CHECK-NEXT:   |-ParmVarDecl {{.+}} 'int'
+// CHECK-NEXT:   `-ParmVarDecl {{.+}} 'int'
+
+}

``




https://github.com/llvm/llvm-project/pull/140714
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[clang] [Clang] Fix an inadvertent overwrite of sub-initializers (PR #140714)

2025-05-20 Thread Younan Zhang via cfe-commits 

https://github.com/zyn0217 created 
https://github.com/llvm/llvm-project/pull/140714

When using InitChecker with VerifyOnly, we create a new designated initializer 
to handle anonymous fields. However in the last call to 
CheckDesignatedInitializer, the subinitializer isn't properly preserved but it 
gets overwritten by the cloned one. Which causes the initializer to reference 
the dependent field, breaking assumptions when we initialize the instantiated 
specialization.

Fixes https://github.com/llvm/llvm-project/issues/67173

>From ec6c540f17d767b3fd882f60b0757e6e4e35442a Mon Sep 17 00:00:00 2001
From: Younan Zhang 
Date: Tue, 20 May 2025 19:19:47 +0800
Subject: [PATCH] [Clang] Fix an inadvertent overwrite of sub-initializers

When using InitChecker with VerifyOnly, we create a new designated
initializer to handle anonymous fields. However in the last call to
CheckDesignatedInitializer, the subinitializer isn't properly
preserved but it gets overwritten by the cloned one. Which causes
the initializer to reference the dependent field, breaking
assumptions when we initialize the instantiated specialization.
---
 clang/docs/ReleaseNotes.rst |  1 +
 clang/lib/Sema/SemaInit.cpp | 12 ++---
 clang/test/SemaTemplate/deduction-guide.cpp | 27 +
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index f04cb7b91788c..6f97cf79c5058 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -690,6 +690,7 @@ Bug Fixes to C++ Support
   certain differences in qualifiers (this could happen during template argument
   deduction or when building a ternary operator). (#GH97005)
 - Fixed type alias CTAD issues involving default template arguments. 
(#GH134471)
+- Fixed CTAD issues when initializing anonymous fields with designated 
initializers. (#GH67173)
 - The initialization kind of elements of structured bindings
   direct-list-initialized from an array is corrected to direct-initialization.
 - Clang no longer crashes when a coroutine is declared ``[[noreturn]]``. 
(#GH127327)
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 9ee8603ff7811..1f204f8306842 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -2791,16 +2791,20 @@ InitListChecker::CheckDesignatedInitializer(const 
InitializedEntity &Entity,
 // initializer list that the child calls see, so that we don't try
 // to re-process the designator.
 unsigned OldIndex = Index;
-IList->setInit(OldIndex, DIE->getInit());
+auto *OldDIE =
+dyn_cast_if_present(IList->getInit(OldIndex));
+if (!OldDIE)
+  OldDIE = DIE;
+IList->setInit(OldIndex, OldDIE->getInit());
 
 CheckSubElementType(Entity, IList, CurrentObjectType, Index, 
StructuredList,
 StructuredIndex, /*DirectlyDesignated=*/true);
 
 // Restore the designated initializer expression in the syntactic
 // form of the initializer list.
-if (IList->getInit(OldIndex) != DIE->getInit())
-  DIE->setInit(IList->getInit(OldIndex));
-IList->setInit(OldIndex, DIE);
+if (IList->getInit(OldIndex) != OldDIE->getInit())
+  OldDIE->setInit(IList->getInit(OldIndex));
+IList->setInit(OldIndex, OldDIE);
 
 return hadError && !prevHadError;
   }
diff --git a/clang/test/SemaTemplate/deduction-guide.cpp 
b/clang/test/SemaTemplate/deduction-guide.cpp
index dabd0cf12f77e..c1ce55e1c8029 100644
--- a/clang/test/SemaTemplate/deduction-guide.cpp
+++ b/clang/test/SemaTemplate/deduction-guide.cpp
@@ -886,3 +886,30 @@ CC c{};
 // CHECK-NEXT:`-ClassTemplateSpecialization {{.+}} 'A'
 
 }
+
+namespace GH67173 {
+
+template  struct Vec2d {
+  struct {
+T x;
+T y;
+  };
+};
+
+void f() {
+  Vec2d v{.x = 1, .y = 2};
+}
+
+// CHECK-LABEL: Dumping GH67173:::
+// CHECK-NEXT: FunctionTemplateDecl {{.+}} implicit 
+// CHECK-NEXT: |-TemplateTypeParmDecl {{.+}} referenced class depth 0 index 0 T
+// CHECK:  |-CXXDeductionGuideDecl {{.+}} implicit  'auto (T, T) -> Vec2d' aggregate
+// CHECK-NEXT: | |-ParmVarDecl {{.+}} col:27 'T'
+// CHECK-NEXT: | `-ParmVarDecl {{.+}} col:27 'T'
+// CHECK-NEXT: `-CXXDeductionGuideDecl {{.+}} implicit used  'auto (int, int) -> GH67173::Vec2d' implicit_instantiation 
aggregate
+// CHECK-NEXT:   |-TemplateArgument type 'int'
+// CHECK-NEXT:   | `-BuiltinType {{.+}} 'int'
+// CHECK-NEXT:   |-ParmVarDecl {{.+}} 'int'
+// CHECK-NEXT:   `-ParmVarDecl {{.+}} 'int'
+
+}

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