[Clang] [Sema] Do not crash on dependent or invalid record decls when -fdump-record-layouts-complete is passed (#83688)

We no longer try to compute and dump the layout of types in cases where that isn’t possible.

This fixes #83684 and #83671.

Author: Sirraide

clang/docs/ReleaseNotes.rst

@@ -321,6 +321,10 @@ Miscellaneous Bug Fixes
 Miscellaneous Clang Crashes Fixed
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+- Do not attempt to dump the layout of dependent types or invalid declarations
+  when ``-fdump-record-layouts-complete`` is passed.
+  Fixes (`#83684 <https://github.com/llvm/llvm-project/issues/83684>`_).
+
 OpenACC Specific Changes
 ------------------------
 

clang/lib/AST/Decl.cpp

@@ -5042,7 +5042,13 @@ void RecordDecl::completeDefinition() {
 
   // Layouts are dumped when computed, so if we are dumping for all complete
   // types, we need to force usage to get types that wouldn't be used elsewhere.
-  if (Ctx.getLangOpts().DumpRecordLayoutsComplete)
+  //
+  // If the type is dependent, then we can't compute its layout because there
+  // is no way for us to know the size or alignment of a dependent type. Also
+  // ignore declarations marked as invalid since 'getASTRecordLayout()' asserts
+  // on that.
+  if (Ctx.getLangOpts().DumpRecordLayoutsComplete && !isDependentType() &&
+      !isInvalidDecl())
     (void)Ctx.getASTRecordLayout(this);
 }
 

clang/test/Layout/dump-complete-invalid.cpp

@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -verify -fsyntax-only -fdump-record-layouts-complete %s
+
+struct Incomplete; // expected-note {{forward declaration}}
+
+// Check we don't crash on trying to print out an invalid declaration.
+struct Invalid : Incomplete {}; // expected-error {{base class has incomplete type}}

clang/test/Layout/dump-complete.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -emit-llvm-only -fdump-record-layouts-complete %s | FileCheck %s
+// RUN: %clang_cc1 -fsyntax-only -fdump-record-layouts-complete %s | FileCheck %s
 
 struct a {
   int x;
@@ -12,7 +12,62 @@ class c {};
 
 class d;
 
+template <typename>
+struct s {
+  int x;
+};
+
+template <typename T>
+struct ts {
+  T x;
+};
+
+template <>
+struct ts<void> {
+  float f;
+};
+
+void f() {
+  ts<int> a;
+  ts<double> b;
+  ts<void> c;
+}
+
+namespace gh83671 {
+template <class _Tp, _Tp __v>
+struct integral_constant {
+  static constexpr const _Tp value = __v;
+  typedef integral_constant type;
+};
+
+template <bool _Val>
+using _BoolConstant = integral_constant<bool, _Val>;
+
+template <class _Tp, class _Up>
+struct is_same : _BoolConstant<__is_same(_Tp, _Up)> {};
+
+template < class _Tp >
+class numeric_limits {};
+
+template < class _Tp >
+class numeric_limits< const _Tp > : public numeric_limits< _Tp > {};
+}
+
+namespace gh83684 {
+template <class Pointer>
+struct AllocationResult {
+  Pointer ptr = nullptr;
+  int count = 0;
+};
+}
+
 // CHECK:          0 | struct a
 // CHECK:          0 | struct b
 // CHECK:          0 | class c
+// CHECK:          0 | struct ts<void>
+// CHECK-NEXT:     0 |   float
+// CHECK:          0 | struct ts<int>
+// CHECK:          0 | struct ts<double>
 // CHECK-NOT:      0 | class d
+// CHECK-NOT:      0 | struct s
+// CHECK-NOT:      0 | struct AllocationResult