Protect against $NNN identifiers
#541
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They must be parenthesized in some contexts to avoid being confused for immediate operands. Fixes: #540
They must be parenthesized in some contexts.
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As a popular extension to ISO C, CompCert C supports identifiers starting with
$. In the generated assembly code, identifiers such as$123can be confused for integer literals. That's the case for x86 (see #540) and for 32-bit ARM.This PR fixes the issue like GCC does, by enclosing identifiers starting with
$in parentheses. Note that this is not necessary for macOS, since all C identifiers are prefixed by_, making_$123unambiguous.The ARM assembly language reference manual suggests the use of vertical bars
|$123|, but these are not implemented by the GNU assembler.A test was added to the small test suite.
Fixes: #540