Disambiguate between a declaration or expression for the 'condition' part of a if/switch/while/for statement.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@57109 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseTentative.cpp b/lib/Parse/ParseTentative.cpp
index 5e4888f..95512a6 100644
--- a/lib/Parse/ParseTentative.cpp
+++ b/lib/Parse/ParseTentative.cpp
@@ -225,6 +225,60 @@
return TPR_ambiguous;
}
+/// isCXXConditionDeclaration - Disambiguates between a declaration or an
+/// expression for a condition of a if/switch/while/for statement.
+/// If during the disambiguation process a parsing error is encountered,
+/// the function returns true to let the declaration parsing code handle it.
+///
+/// condition:
+/// expression
+/// type-specifier-seq declarator '=' assignment-expression
+/// [GNU] type-specifier-seq declarator simple-asm-expr[opt] attributes[opt]
+/// '=' assignment-expression
+///
+bool Parser::isCXXConditionDeclaration() {
+ TentativeParsingResult TPR = isCXXDeclarationSpecifier();
+ if (TPR != TPR_ambiguous)
+ return TPR != TPR_false; // Returns true for TPR_true or TPR_error.
+
+ // FIXME: Add statistics about the number of ambiguous statements encountered
+ // and how they were resolved (number of declarations+number of expressions).
+
+ // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
+ // We need tentative parsing...
+
+ TentativeParsingAction PA(*this);
+
+ // type-specifier-seq
+ if (Tok.is(tok::kw_typeof))
+ TryParseTypeofSpecifier();
+ else
+ ConsumeToken();
+ assert(Tok.is(tok::l_paren) && "Expected '('");
+
+ // declarator
+ TPR = TryParseDeclarator(false/*mayBeAbstract*/);
+
+ PA.Revert();
+
+ // In case of an error, let the declaration parsing code handle it.
+ if (TPR == TPR_error)
+ return true;
+
+ if (TPR == TPR_ambiguous) {
+ // '='
+ // [GNU] simple-asm-expr[opt] attributes[opt]
+ if (Tok.is(tok::equal) ||
+ Tok.is(tok::kw_asm) || Tok.is(tok::kw___attribute))
+ TPR = TPR_true;
+ else
+ TPR = TPR_false;
+ }
+
+ assert(TPR == TPR_true || TPR == TPR_false);
+ return TPR == TPR_true;
+}
+
/// declarator:
/// direct-declarator
/// ptr-operator declarator