On Fri, 19 Aug 2016, David Malcolm wrote: > Please could you take this opportunity to add some examples to the > header comment for that function, both for the common cases e.g. "f", > and for the new suffixes; nothing in the patch body appears to document > them. (ideally, referencing the standard). > > Also, it would be good to add some more comments to the function body. > For example, in this hunk: > > - if (f + d + l + w + q > 1 || i > 1) > + if (f + d + l + w + q + fn + fnx > 1 || i > 1) > > should it read something like : > /* Reject duplicate suffixes, contradictory suffixes [...] */ > > where "[...]" is something relating to fn + fnx, which I can't figure > out in the absence of the standard you're referring to.
How does this seem? I think <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1945.pdf> was the last public draft of TS 18661-3 before publication. Index: libcpp/expr.c =================================================================== --- libcpp/expr.c (revision 239623) +++ libcpp/expr.c (working copy) @@ -86,16 +86,53 @@ static cpp_num parse_has_include (cpp_reader *, en /* Subroutine of cpp_classify_number. S points to a float suffix of length LEN, possibly zero. Returns 0 for an invalid suffix, or a - flag vector describing the suffix. */ + flag vector (of CPP_N_* bits) describing the suffix. */ static unsigned int interpret_float_suffix (cpp_reader *pfile, const uchar *s, size_t len) { size_t flags; - size_t f, d, l, w, q, i; + size_t f, d, l, w, q, i, fn, fnx, fn_bits; flags = 0; - f = d = l = w = q = i = 0; + f = d = l = w = q = i = fn = fnx = fn_bits = 0; + /* The following decimal float suffixes, from TR 24732:2009 and TS + 18661-2:2015, are supported: + + df, DF - _Decimal32. + dd, DD - _Decimal64. + dl, DL - _Decimal128. + + The dN and DN suffixes for _DecimalN, and dNx and DNx for + _DecimalNx, defined in TS 18661-3:2015, are not supported. + + Fixed-point suffixes, from TR 18037:2008, are supported. They + consist of three parts, in order: + + (i) An optional u or U, for unsigned types. + + (ii) An optional h or H, for short types, or l or L, for long + types, or ll or LL, for long long types. Use of ll or LL is a + GNU extension. + + (iii) r or R, for _Fract types, or k or K, for _Accum types. + + Otherwise the suffix is for a binary or standard floating-point + type. Such a suffix, or the absence of a suffix, may be preceded + or followed by i, I, j or J, to indicate an imaginary number with + the corresponding complex type. The following suffixes for + binary or standard floating-point types are supported: + + f, F - float (ISO C and C++). + l, L - long double (ISO C and C++). + d, D - double, even with the FLOAT_CONST_DECIMAL64 pragma in + operation (from TR 24732:2009; the pragma and the suffix + are not included in TS 18661-2:2015). + w, W - machine-specific type such as __float80 (GNU extension). + q, Q - machine-specific type such as __float128 (GNU extension). + fN, FN - _FloatN (TS 18661-3:2015). + fNx, FNx - _FloatNx (TS 18661-3:2015). */ + /* Process decimal float suffixes, which are two letters starting with d or D. Order and case are significant. */ if (len == 2 && (*s == 'd' || *s == 'D')) @@ -172,21 +209,65 @@ interpret_float_suffix (cpp_reader *pfile, const u /* In any remaining valid suffix, the case and order don't matter. */ while (len--) - switch (s[len]) - { - case 'f': case 'F': f++; break; - case 'd': case 'D': d++; break; - case 'l': case 'L': l++; break; - case 'w': case 'W': w++; break; - case 'q': case 'Q': q++; break; - case 'i': case 'I': - case 'j': case 'J': i++; break; - default: - return 0; - } + { + switch (s[0]) + { + case 'f': case 'F': + f++; + if (len > 0 + && !CPP_OPTION (pfile, cplusplus) + && s[1] >= '1' + && s[1] <= '9' + && fn_bits == 0) + { + f--; + while (len > 0 + && s[1] >= '0' + && s[1] <= '9' + && fn_bits < CPP_FLOATN_MAX) + { + fn_bits = fn_bits * 10 + (s[1] - '0'); + len--; + s++; + } + if (len > 0 && s[1] == 'x') + { + fnx++; + len--; + s++; + } + else + fn++; + } + break; + case 'd': case 'D': d++; break; + case 'l': case 'L': l++; break; + case 'w': case 'W': w++; break; + case 'q': case 'Q': q++; break; + case 'i': case 'I': + case 'j': case 'J': i++; break; + default: + return 0; + } + s++; + } - if (f + d + l + w + q > 1 || i > 1) + /* Reject any case of multiple suffixes specifying types, multiple + suffixes specifying an imaginary constant, _FloatN or _FloatNx + suffixes for invalid values of N, and _FloatN suffixes for values + of N larger than can be represented in the return value. The + caller is responsible for rejecting _FloatN suffixes where + _FloatN is not supported on the chosen target. */ + if (f + d + l + w + q + fn + fnx > 1 || i > 1) return 0; + if (fn_bits > CPP_FLOATN_MAX) + return 0; + if (fnx && fn_bits != 32 && fn_bits != 64 && fn_bits != 128) + return 0; + if (fn && fn_bits != 16 && fn_bits % 32 != 0) + return 0; + if (fn && fn_bits == 96) + return 0; if (i && !CPP_OPTION (pfile, ext_numeric_literals)) return 0; @@ -199,7 +280,10 @@ interpret_float_suffix (cpp_reader *pfile, const u d ? CPP_N_MEDIUM : l ? CPP_N_LARGE : w ? CPP_N_MD_W : - q ? CPP_N_MD_Q : CPP_N_DEFAULT)); + q ? CPP_N_MD_Q : + fn ? CPP_N_FLOATN | (fn_bits << CPP_FLOATN_SHIFT) : + fnx ? CPP_N_FLOATNX | (fn_bits << CPP_FLOATN_SHIFT) : + CPP_N_DEFAULT)); } /* Return the classification flags for a float suffix. */ -- Joseph S. Myers jos...@codesourcery.com
