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[flang] Refine tokenization trick that hid macro name #121990

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Merged
merged 1 commit into from
Jan 8, 2025
Merged

[flang] Refine tokenization trick that hid macro name #121990

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19 changes: 16 additions & 3 deletions flang/lib/Parser/prescan.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -709,9 +709,22 @@ bool Prescanner::NextToken(TokenSequence &tokens) {
QuotedCharacterLiteral(tokens, start);
} else if (IsLetter(*at_) && !preventHollerith_ &&
parenthesisNesting_ > 0) {
// Handles FORMAT(3I9HHOLLERITH) by skipping over the first I so that
// we don't misrecognize I9HOLLERITH as an identifier in the next case.
EmitCharAndAdvance(tokens, *at_);
const char *p{at_};
int digits{0};
for (;; ++digits) {
++p;
if (InFixedFormSource()) {
p = SkipWhiteSpace(p);
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@eugeneepshteyn eugeneepshteyn Jan 9, 2025

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Could p possibly walk off the end of the buffer here?

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@eugeneepshteyn eugeneepshteyn Jan 9, 2025

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(Ghithub had issues. My comment was meant for line 715 ++p.)

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@klausler klausler Jan 9, 2025

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I don't think so; source files are normalized so that their last lines always end with a newline.

}
if (!IsDecimalDigit(*p)) {
break;
}
}
if (digits > 0 && (*p == 'h' || *p == 'H')) {
// Handles FORMAT(3I9HHOLLERITH) by skipping over the first I so that
// we don't misrecognize I9HOLLERITH as an identifier in the next case.
EmitCharAndAdvance(tokens, *at_);
}
}
preventHollerith_ = false;
} else if (*at_ == '.') {
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5 changes: 5 additions & 0 deletions flang/test/Preprocessing/bug129131.F
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Original file line number Diff line number Diff line change
@@ -0,0 +1,5 @@
! RUN: %flang -fc1 -fdebug-unparse %s 2>&1 | FileCheck %s
! CHECK: PRINT *, 2_4
#define a ,3
print *, mod(5 a)
end
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