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[Lex] Fix handling numerical literals ending with ' and signed exponent. 

For input `0'e+1` lexer tokenized as numeric constant only `0'e`. Later
NumericLiteralParser skipped 0 and ' as digits and parsed `e+1` as valid
exponent going past the end of the token. Because it didn't mark numeric
literal as having an error, it continued parsing and tried to expandUCNs
with StringRef of length -2.

The fix is not to parse exponent when we reached the end of token.

Discovered by OSS-Fuzz:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=4588

rdar://problem/36076719

Reviewers: rsmith, t.p.northover

Reviewed By: rsmith

Subscribers: cfe-commits, jkorous-apple

Differential Revision: https://reviews.llvm.org/D41834

llvm-svn: 324419
This commit is contained in:
Volodymyr Sapsai 2018-02-06 22:39:25 +00:00
parent 64626b344b
commit 579f0b307c
2 changed files with 17 additions and 9 deletions
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24
clang/lib/Lex/LiteralSupport.cpp
View File

@ -738,15 +738,17 @@ void NumericLiteralParser::ParseDecimalOrOctalCommon(SourceLocation TokLoc){
s++;
radix = 10;
saw_exponent = true;
if (*s == '+' || *s == '-') s++; // sign
if (s != ThisTokEnd && (*s == '+' || *s == '-')) s++; // sign
const char *first_non_digit = SkipDigits(s);
if (containsDigits(s, first_non_digit)) {
checkSeparator(TokLoc, s, CSK_BeforeDigits);
s = first_non_digit;
} else {
PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-ThisTokBegin),
diag::err_exponent_has_no_digits);
hadError = true;
if (!hadError) {
PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-ThisTokBegin),
diag::err_exponent_has_no_digits);
hadError = true;
}
return;
}
}
@ -787,10 +789,12 @@ void NumericLiteralParser::checkSeparator(SourceLocation TokLoc,
} else if (Pos == ThisTokEnd)
return;
if (isDigitSeparator(*Pos))
if (isDigitSeparator(*Pos)) {
PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Pos - ThisTokBegin),
diag::err_digit_separator_not_between_digits)
<< IsAfterDigits;
hadError = true;
}
}
/// ParseNumberStartingWithZero - This method is called when the first character
@ -840,12 +844,14 @@ void NumericLiteralParser::ParseNumberStartingWithZero(SourceLocation TokLoc) {
const char *Exponent = s;
s++;
saw_exponent = true;
if (*s == '+' || *s == '-') s++; // sign
if (s != ThisTokEnd && (*s == '+' || *s == '-')) s++; // sign
const char *first_non_digit = SkipDigits(s);
if (!containsDigits(s, first_non_digit)) {
PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-ThisTokBegin),
diag::err_exponent_has_no_digits);
hadError = true;
if (!hadError) {
PP.Diag(PP.AdvanceToTokenCharacter(TokLoc, Exponent-ThisTokBegin),
diag::err_exponent_has_no_digits);
hadError = true;
}
return;
}
checkSeparator(TokLoc, s, CSK_BeforeDigits);

2
clang/test/Lexer/cxx1y_digit_separators.cpp
View File

@ -51,6 +51,8 @@ namespace floating {
float u = 0x.'p1f; // expected-error {{hexadecimal floating literal requires a significand}}
float v = 0e'f; // expected-error {{exponent has no digits}}
float w = 0x0p'f; // expected-error {{exponent has no digits}}
float x = 0'e+1; // expected-error {{digit separator cannot appear at end of digit sequence}}
float y = 0x0'p+1; // expected-error {{digit separator cannot appear at end of digit sequence}}
}
#line 123'456