[PATCH] D63975: Warn when ScopeDepthOrObjCQuals overflows

[Mark de Wever via Phabricator via cfe-commits]

Mordante updated this revision to Diff 209513.
Mordante added a comment.

Moved the test out of the loop as suggested by rjmccall.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D63975/new/

https://reviews.llvm.org/D63975

Files:
  clang/include/clang/AST/Decl.h
  clang/include/clang/Basic/DiagnosticParseKinds.td
  clang/lib/Parse/ParseDecl.cpp
  clang/test/Parser/nested_function_prototype_overflow.cpp
  clang/test/Parser/nested_lambda_overflow.cpp


Index: clang/test/Parser/nested_lambda_overflow.cpp
===================================================================
--- /dev/null
+++ clang/test/Parser/nested_lambda_overflow.cpp
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 %s -fsyntax-only
+// RUN: not %clang_cc1 %s -fsyntax-only -DFAIL 2>&1 | FileCheck %s
+
+auto foo = [](void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(
+#ifdef FAIL
+void (*f)()
+#endif
+))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))) {};
+// CHECK: fatal error: function scope depth exceeded maximum of 127
Index: clang/test/Parser/nested_function_prototype_overflow.cpp
===================================================================
--- /dev/null
+++ clang/test/Parser/nested_function_prototype_overflow.cpp
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 %s -fsyntax-only
+// RUN: not %clang_cc1 %s -fsyntax-only -DFAIL 2>&1 | FileCheck %s
+
+void foo(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(void (*f)(
+#ifdef FAIL
+void (*f)()
+#endif
+)))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))))));
+// CHECK: fatal error: function scope depth exceeded maximum of 127
Index: clang/lib/Parse/ParseDecl.cpp
===================================================================
--- clang/lib/Parse/ParseDecl.cpp
+++ clang/lib/Parse/ParseDecl.cpp
@@ -6510,6 +6510,19 @@
        ParsedAttributes &FirstArgAttrs,
        SmallVectorImpl<DeclaratorChunk::ParamInfo> &ParamInfo,
        SourceLocation &EllipsisLoc) {
+
+  // Avoid exceeding the maximum function scope depth.
+  // See https://bugs.llvm.org/show_bug.cgi?id=19607
+  // Note Sema::ActOnParamDeclarator calls ParmVarDecl::setScopeInfo with
+  // getFunctionPrototypeDepth() - 1.
+  if (getCurScope()->getFunctionPrototypeDepth() - 1 >
+      ParmVarDecl::getMaxFunctionScopeDepth()) {
+    Diag(Tok.getLocation(), diag::err_function_scope_depth_exceeded)
+        << ParmVarDecl::getMaxFunctionScopeDepth();
+    cutOffParsing();
+    return;
+  }
+
   do {
     // FIXME: Issue a diagnostic if we parsed an attribute-specifier-seq
     // before deciding this was a parameter-declaration-clause.
Index: clang/include/clang/Basic/DiagnosticParseKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticParseKinds.td
+++ clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -326,6 +326,8 @@
 def err_argument_required_after_attribute : Error<
   "argument required after attribute">;
 def err_missing_param : Error<"expected parameter declarator">;
+def err_function_scope_depth_exceeded : Error<
+  "function scope depth exceeded maximum of %0">, DefaultFatal;
 def err_missing_comma_before_ellipsis : Error<
   "C requires a comma prior to the ellipsis in a variadic function type">;
 def err_unexpected_typedef_ident : Error<
Index: clang/include/clang/AST/Decl.h
===================================================================
--- clang/include/clang/AST/Decl.h
+++ clang/include/clang/AST/Decl.h
@@ -905,11 +905,13 @@
     /// Whether this parameter is an ObjC method parameter or not.
     unsigned IsObjCMethodParam : 1;
 
+    enum { NumScopeDepthOrObjCQualsBits = 7 };
+
     /// If IsObjCMethodParam, a Decl::ObjCDeclQualifier.
     /// Otherwise, the number of function parameter scopes enclosing
     /// the function parameter scope in which this parameter was
     /// declared.
-    unsigned ScopeDepthOrObjCQuals : 7;
+    unsigned ScopeDepthOrObjCQuals : NumScopeDepthOrObjCQualsBits;
 
     /// The number of parameters preceding this parameter in the
     /// function parameter scope in which it was declared.
@@ -1613,6 +1615,10 @@
     return ParmVarDeclBits.ScopeDepthOrObjCQuals;
   }
 
+  static constexpr unsigned getMaxFunctionScopeDepth() {
+    return (1u << ParmVarDeclBitfields::NumScopeDepthOrObjCQualsBits) - 1;
+  }
+
   /// Returns the index of this parameter in its prototype or method scope.
   unsigned getFunctionScopeIndex() const {
     return getParameterIndex();


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