[MC] Fix floating-point literal lexing.
This patch has three related fixes to improve float literal lexing:
1. Make AsmLexer::LexDigit handle floats without a decimal point more
consistently.
2. Make AsmLexer::LexFloatLiteral print an error for floats which are
apparently missing an "e".
3. Make APFloat::convertFromString use binutils-compatible exponent
parsing.
Together, this fixes some cases where a float would be incorrectly
rejected, fixes some cases where the compiler would crash, and improves
diagnostics in some cases.
Patch by Brandon Jones.
Differential Revision: https://reviews.llvm.org/D57321
llvm-svn: 357214
diff --git a/llvm/lib/Support/APFloat.cpp b/llvm/lib/Support/APFloat.cpp
index 3ebed5b..208950d 100644
--- a/llvm/lib/Support/APFloat.cpp
+++ b/llvm/lib/Support/APFloat.cpp
@@ -198,7 +198,10 @@
const unsigned int overlargeExponent = 24000; /* FIXME. */
StringRef::iterator p = begin;
- assert(p != end && "Exponent has no digits");
+ // Treat no exponent as 0 to match binutils
+ if (p == end || ((*p == '-' || *p == '+') && (p + 1) == end)) {
+ return 0;
+ }
isNegative = (*p == '-');
if (*p == '-' || *p == '+') {