[PATCH] D151033: [clang][AST] TextNodeDumper should not evaluate the initializer of constexpr variable template definition

Takuya Shimizu via Phabricator via cfe-commits Sat, 20 May 2023 09:53:44 -0700

hazohelet created this revision.
hazohelet added reviewers: aaron.ballman, erichkeane, tbaeder.
Herald added a project: All.
hazohelet requested review of this revision.
Herald added a project: clang.


`TextNodeDumper` enabed through `-ast-dump` flag should not evlauate the 
initializer when it visits a constexpr `VarDecl` node if it describes a 
variable template.

I found a crashing case fixed by this change and added it as a test case.
`template <typename T> constexpr T call_init(0);`
Link: https://godbolt.org/z/3bG9Pjj5E

This is a fix for the regression caused by D146358 
<https://reviews.llvm.org/D146358>


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D151033

Files:
  clang/docs/ReleaseNotes.rst
  clang/lib/AST/TextNodeDumper.cpp
  clang/test/AST/ast-dump-decl.cpp


Index: clang/test/AST/ast-dump-decl.cpp
===================================================================
--- clang/test/AST/ast-dump-decl.cpp
+++ clang/test/AST/ast-dump-decl.cpp
@@ -818,3 +818,31 @@
 // CHECK:       `-TextComment
 // CHECK: VarDecl {{.*}} Test 'int' extern
 // CHECK-NOT: FullComment
+
+namespace TestConstexprVariableTemplateWithInitializer {
+  template<typename T> constexpr T foo{};
+  // CHECK:      VarTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-1]]:3, col:40> 
col:36 foo
+  // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 
referenced typename depth 0 index 0 T
+  // CHECK-NEXT: `-VarDecl 0x{{.+}} <col:24, col:40> col:36 foo 'const T' 
constexpr listinit
+  // CHECK-NEXT:  `-InitListExpr 0x{{.+}} <col:39, col:40> 'void'
+
+  template <typename _Tp>
+  struct in_place_type_t {
+    explicit in_place_type_t() = default;
+  };
+
+  template <typename _Tp>
+  inline constexpr in_place_type_t<_Tp> in_place_type{};
+  // CHECK:     -VarTemplateDecl 0x{{.+}} <line:[[@LINE-2]]:3, 
line:[[@LINE-1]]:55> col:41 in_place_type
+  // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <line:[[@LINE-3]]:13, col:22> 
col:22 referenced typename depth 0 index 0 _Tp
+  // CHECK-NEXT: `-VarDecl 0x{{.+}} <line:[[@LINE-3]]:3, col:55> col:41 
in_place_type 'const in_place_type_t<_Tp>':'const in_place_type_t<_Tp>' inline 
constexpr listinit
+  // CHECK-NEXT:  `-InitListExpr 0x{{.+}} <col:54, col:55> 'void'
+
+  template <typename T> constexpr T call_init(0);
+  // CHECK:     -VarTemplateDecl 0x{{.+}} <line:[[@LINE-1]]:3, col:48> col:37 
call_init
+  // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <col:13, col:22> col:22 
referenced typename depth 0 index 0 T
+  // CHECK-NEXT: `-VarDecl 0x{{.+}} <col:25, col:48> col:37 call_init 'const 
T' constexpr callinit
+  // CHECK-NEXT:  `-ParenListExpr 0x{{.+}} <col:46, col:48> 'NULL TYPE'
+  // CHECK-NEXT:   `-IntegerLiteral 0x{{.+}} <col:47> 'int' 0
+
+}
Index: clang/lib/AST/TextNodeDumper.cpp
===================================================================
--- clang/lib/AST/TextNodeDumper.cpp
+++ clang/lib/AST/TextNodeDumper.cpp
@@ -1821,7 +1821,8 @@
   if (D->hasInit()) {
     const Expr *E = D->getInit();
     // Only dump the value of constexpr VarDecls for now.
-    if (E && !E->isValueDependent() && D->isConstexpr()) {
+    if (E && !E->isValueDependent() && D->isConstexpr() &&
+        !D->getDescribedVarTemplate()) {
       const APValue *Value = D->evaluateValue();
       if (Value)
         AddChild("value", [=] { Visit(*Value, E->getType()); });
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -418,6 +418,8 @@
 - Propagate the value-dependent bit for VAArgExpr. Fixes a crash where a
   __builtin_va_arg call has invalid arguments.
   (`#62711 <https://github.com/llvm/llvm-project/issues/62711>`_).
+- Clang `TextNodeDumper` enabled through `-ast-dump` flag no longer evaluates 
the
+  initializer of constexpr `VarDecl` that describes a variable template.
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Index: clang/test/AST/ast-dump-decl.cpp
===================================================================
--- clang/test/AST/ast-dump-decl.cpp
+++ clang/test/AST/ast-dump-decl.cpp
@@ -818,3 +818,31 @@
 // CHECK:       `-TextComment
 // CHECK: VarDecl {{.*}} Test 'int' extern
 // CHECK-NOT: FullComment
+
+namespace TestConstexprVariableTemplateWithInitializer {
+  template<typename T> constexpr T foo{};
+  // CHECK:      VarTemplateDecl 0x{{.+}} <{{.+}}:[[@LINE-1]]:3, col:40> col:36 foo
+  // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <col:12, col:21> col:21 referenced typename depth 0 index 0 T
+  // CHECK-NEXT: `-VarDecl 0x{{.+}} <col:24, col:40> col:36 foo 'const T' constexpr listinit
+  // CHECK-NEXT:  `-InitListExpr 0x{{.+}} <col:39, col:40> 'void'
+
+  template <typename _Tp>
+  struct in_place_type_t {
+    explicit in_place_type_t() = default;
+  };
+
+  template <typename _Tp>
+  inline constexpr in_place_type_t<_Tp> in_place_type{};
+  // CHECK:     -VarTemplateDecl 0x{{.+}} <line:[[@LINE-2]]:3, line:[[@LINE-1]]:55> col:41 in_place_type
+  // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <line:[[@LINE-3]]:13, col:22> col:22 referenced typename depth 0 index 0 _Tp
+  // CHECK-NEXT: `-VarDecl 0x{{.+}} <line:[[@LINE-3]]:3, col:55> col:41 in_place_type 'const in_place_type_t<_Tp>':'const in_place_type_t<_Tp>' inline constexpr listinit
+  // CHECK-NEXT:  `-InitListExpr 0x{{.+}} <col:54, col:55> 'void'
+
+  template <typename T> constexpr T call_init(0);
+  // CHECK:     -VarTemplateDecl 0x{{.+}} <line:[[@LINE-1]]:3, col:48> col:37 call_init
+  // CHECK-NEXT: |-TemplateTypeParmDecl 0x{{.+}} <col:13, col:22> col:22 referenced typename depth 0 index 0 T
+  // CHECK-NEXT: `-VarDecl 0x{{.+}} <col:25, col:48> col:37 call_init 'const T' constexpr callinit
+  // CHECK-NEXT:  `-ParenListExpr 0x{{.+}} <col:46, col:48> 'NULL TYPE'
+  // CHECK-NEXT:   `-IntegerLiteral 0x{{.+}} <col:47> 'int' 0
+
+}
Index: clang/lib/AST/TextNodeDumper.cpp
===================================================================
--- clang/lib/AST/TextNodeDumper.cpp
+++ clang/lib/AST/TextNodeDumper.cpp
@@ -1821,7 +1821,8 @@
   if (D->hasInit()) {
     const Expr *E = D->getInit();
     // Only dump the value of constexpr VarDecls for now.
-    if (E && !E->isValueDependent() && D->isConstexpr()) {
+    if (E && !E->isValueDependent() && D->isConstexpr() &&
+        !D->getDescribedVarTemplate()) {
       const APValue *Value = D->evaluateValue();
       if (Value)
         AddChild("value", [=] { Visit(*Value, E->getType()); });
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -418,6 +418,8 @@
 - Propagate the value-dependent bit for VAArgExpr. Fixes a crash where a
   __builtin_va_arg call has invalid arguments.
   (`#62711 <https://github.com/llvm/llvm-project/issues/62711>`_).
+- Clang `TextNodeDumper` enabled through `-ast-dump` flag no longer evaluates the
+  initializer of constexpr `VarDecl` that describes a variable template.
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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[PATCH] D151033: [clang][AST] TextNodeDumper should not evaluate the initializer of constexpr variable template definition

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