Fix a few more bugs in preprocessor expressions w.r.t. ?:. Now I
think it is really right. :) This fixes PR2284.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@50665 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PPExpressions.cpp b/lib/Lex/PPExpressions.cpp
index fb8bae5..5ced05c 100644
--- a/lib/Lex/PPExpressions.cpp
+++ b/lib/Lex/PPExpressions.cpp
@@ -362,8 +362,8 @@
case tok::pipe: return 7;
case tok::ampamp: return 6;
case tok::pipepipe: return 5;
- case tok::comma: return 4;
- case tok::question: return 3;
+ case tok::question: return 4;
+ case tok::comma: return 3;
case tok::colon: return 2;
case tok::r_paren: return 0; // Lowest priority, end of expr.
case tok::eom: return 0; // Lowest priority, end of macro.
@@ -432,14 +432,25 @@
return true;
}
- bool isRightAssoc = Operator == tok::question;
+ // Decide whether to include the next binop in this subexpression. For
+ // example, when parsing x+y*z and looking at '*', we want to recursively
+ // handling y*z as a single subexpression. We do this because the
+ // precedence of * is higher than that of +. The only strange case we have
+ // to handle here is for the ?: operator, where the precedence is actually
+ // lower than the LHS of the '?'. The grammar rule is:
+ //
+ // conditional-expression ::=
+ // logical-OR-expression ? expression : conditional-expression
+ // where 'expression' is actually comma-expression.
+ unsigned RHSPrec;
+ if (Operator == tok::question)
+ // The RHS of "?" should be maximally consumed as an expression.
+ RHSPrec = getPrecedence(tok::comma);
+ else // All others should munch while higher precedence.
+ RHSPrec = ThisPrec+1;
- // Get the precedence of the operator to the right of the RHS. If it binds
- // more tightly with RHS than we do, evaluate it completely first.
- if (ThisPrec < PeekPrec ||
- (ThisPrec == PeekPrec && isRightAssoc)) {
- if (EvaluateDirectiveSubExpr(RHS, ThisPrec+!isRightAssoc,
- PeekTok, RHSIsLive, PP))
+ if (PeekPrec >= RHSPrec) {
+ if (EvaluateDirectiveSubExpr(RHS, RHSPrec, PeekTok, RHSIsLive, PP))
return true;
PeekPrec = getPrecedence(PeekTok.getKind());
}
@@ -609,8 +620,8 @@
if (EvaluateValue(AfterColonVal, PeekTok, DT, AfterColonLive, PP))
return true;
- // Parse anything after the : RHS that has a higher precedence than ?.
- if (EvaluateDirectiveSubExpr(AfterColonVal, ThisPrec+1,
+ // Parse anything after the : with the same precedence as ?.
+ if (EvaluateDirectiveSubExpr(AfterColonVal, ThisPrec,
PeekTok, AfterColonLive, PP))
return true;
@@ -681,7 +692,8 @@
// Otherwise, we must have a binary operator (e.g. "#if 1 < 2"), so parse the
// operator and the stuff after it.
- if (EvaluateDirectiveSubExpr(ResVal, 1, Tok, true, *this)) {
+ if (EvaluateDirectiveSubExpr(ResVal, getPrecedence(tok::question),
+ Tok, true, *this)) {
// Parse error, skip the rest of the macro line.
if (Tok.isNot(tok::eom))
DiscardUntilEndOfDirective();