[PATCH] D78284: [AST] Fix an undefine behavior when creating an empty recovery expr.

[Haojian Wu via Phabricator via cfe-commits]

hokein created this revision.
hokein added a reviewer: sammccall.
Herald added a project: clang.

We forgot to initialize the NumExpr member in one of the constructors,
which leads crashes in preamble serialization.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D78284

Files:
  clang/include/clang/AST/Expr.h
  clang/lib/AST/Expr.cpp
  clang/test/PCH/cxx-recovery-expr.cpp


Index: clang/test/PCH/cxx-recovery-expr.cpp
===================================================================
--- /dev/null
+++ clang/test/PCH/cxx-recovery-expr.cpp
@@ -0,0 +1,13 @@
+// Test with pch.
+// RUN: %clang_cc1 -emit-pch -frecovery-ast -fallow-pch-with-compiler-errors -o %t %s
+// RUN: %clang_cc1 -include-pch %t -fno-validate-pch -emit-llvm -o - %s
+
+#ifndef HEADER
+#define HEADER
+
+int func(int);
+int s = func();
+
+#else
+
+#endif
Index: clang/lib/AST/Expr.cpp
===================================================================
--- clang/lib/AST/Expr.cpp
+++ clang/lib/AST/Expr.cpp
@@ -4574,7 +4574,7 @@
 RecoveryExpr *RecoveryExpr::CreateEmpty(ASTContext &Ctx, unsigned NumSubExprs) {
   void *Mem = Ctx.Allocate(totalSizeToAlloc<Expr *>(NumSubExprs),
                            alignof(RecoveryExpr));
-  return new (Mem) RecoveryExpr(EmptyShell());
+  return new (Mem) RecoveryExpr(EmptyShell(), NumSubExprs);
 }
 
 void OMPArrayShapingExpr::setDimensions(ArrayRef<Expr *> Dims) {
Index: clang/include/clang/AST/Expr.h
===================================================================
--- clang/include/clang/AST/Expr.h
+++ clang/include/clang/AST/Expr.h
@@ -6034,7 +6034,8 @@
 private:
   RecoveryExpr(ASTContext &Ctx, SourceLocation BeginLoc, SourceLocation EndLoc,
                ArrayRef<Expr *> SubExprs);
-  RecoveryExpr(EmptyShell Empty) : Expr(RecoveryExprClass, Empty) {}
+  RecoveryExpr(EmptyShell Empty, unsigned NumSubExprs)
+      : Expr(RecoveryExprClass, Empty), NumExprs(NumSubExprs) {}
 
   size_t numTrailingObjects(OverloadToken<Stmt *>) const { return NumExprs; }
 


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