cosmopolitan/test/libc/stdio
Gabriel Ravier e3d28de8a6
Fix UB in gdtoa hexadecimal float scanf and strtod (#1288)
When reading hexadecimal floats, cosmopolitan would previously sometimes
print a number of warnings relating to undefined behavior on left shift:

third_party/gdtoa/gethex.c:172: ubsan warning: signed left shift changed
sign bit or overflowed 12 'int' 28 'int' is undefined behavior

This is because gdtoa assumes left shifts are safe when overflow happens
even on signed integers - this is false: the C standard considers it UB.
This is easy to fix, by simply casting the shifted value to unsigned, as
doing so does not change the value or the semantics of the left shifting
(except for avoiding the undefined behavior, as the C standard specifies
that unsigned overflow yields wraparound, avoiding undefined behaviour).

This commit does this, and adds a testcase that previously triggered UB.
(this also adds test macros to test for exact float equality, instead of
the existing {EXPECT,ASSERT}_FLOAT_EQ macros which only tests inputs for
being "almost equal" (with a significant epsilon) whereas exact equality
makes more sense for certain things such as reading floats from strings,
and modifies other testcases for sscanf/fscanf of floats to utilize it).
2024-09-14 17:11:04 -07:00
..
BUILD.mk Fix bugs in poll(), select(), ppoll(), and pselect() 2024-09-02 00:29:52 -07:00
crypt_test.c Run clang-format (#1197) 2024-06-01 16:30:43 -04:00
devrand_test.c Run clang-format (#1197) 2024-06-01 16:30:43 -04:00
dirstream_test.c Delete ASAN 2024-06-22 05:45:49 -07:00
dtoa_test.c Remove .internal from more header filenames 2024-08-04 12:52:25 -07:00
dumphexc_test.c Run clang-format (#1197) 2024-06-01 16:30:43 -04:00
ecvt_test.c Fix ecvt/fcvt issues w.r.t. value==0 and ndigit==0 (#1282) 2024-09-07 18:08:11 -07:00
fds_torture_test.c Apply clang-format update to repo (#1154) 2024-04-25 10:38:00 -07:00
fgetln_test.c Run clang-format (#1197) 2024-06-01 16:30:43 -04:00
fgets_test.c Apply clang-format update to repo (#1154) 2024-04-25 10:38:00 -07:00
fgetwc_test.c flip et / noet in modelines 2023-12-07 22:17:11 -05:00
fmemopen_test.c Bring back gc() function 2024-01-08 10:26:28 -08:00
fmt_test.c Support printf %n directive 2024-07-28 22:27:06 -07:00
fprintf_test.c Apply clang-format update to repo (#1154) 2024-04-25 10:38:00 -07:00
fputc_test.c Make fread() more consistent with glibc 2024-08-17 02:57:22 -07:00
fputs_test.c Bring back gc() function 2024-01-08 10:26:28 -08:00
fread_test.c Make fread() more consistent with glibc 2024-08-17 02:57:22 -07:00
freopen_test.c Fix fread() with 2gb+ sizes 2024-05-24 19:28:23 -07:00
fscanf_test.c Fix UB in gdtoa hexadecimal float scanf and strtod (#1288) 2024-09-14 17:11:04 -07:00
fseeko_test.c flip et / noet in modelines 2023-12-07 22:17:11 -05:00
ftell_test.c Bring back gc() function 2024-01-08 10:26:28 -08:00
fwrite_test.c Implement proper time zone support 2024-05-04 23:06:37 -07:00
getdelim_test.c Apply clang-format update to repo (#1154) 2024-04-25 10:38:00 -07:00
getentropy_test.c Remove .internal from more header filenames 2024-08-04 12:52:25 -07:00
gz_test.c flip et / noet in modelines 2023-12-07 22:17:11 -05:00
iconv_test.c Run clang-format (#1197) 2024-06-01 16:30:43 -04:00
joinstrlist_test.c Run clang-format (#1197) 2024-06-01 16:30:43 -04:00
lemur64_test.c Fix issues with previous commit 2024-09-10 01:59:46 -07:00
memory_test.c Bring back gc() function 2024-01-08 10:26:28 -08:00
mt19937_test.c Remove .internal from more header filenames 2024-08-04 12:52:25 -07:00
palandprintf_test.c Get rid of .internal.h convention in LIBC_INTRIN 2024-07-19 19:38:00 -07:00
popen_test.c Improve lock hierarchy 2024-07-24 16:05:48 -07:00
rand_test.c Run clang-format (#1197) 2024-06-01 16:30:43 -04:00
rngset_test.c flip et / noet in modelines 2023-12-07 22:17:11 -05:00
snprintf_enomem_test.c Fix printf funcs on memory pressure with floats (#1275) 2024-09-01 14:42:14 -07:00
snprintf_test.c Partially fix printf hex float numbers/%a rounding (#1286) 2024-09-10 20:42:52 -07:00
sprintf_s.inc flip et / noet in modelines 2023-12-07 22:17:11 -05:00
sprintf_s_test.c Get rid of .internal.h convention in LIBC_INTRIN 2024-07-19 19:38:00 -07:00
sscanf_test.c Fix UB in gdtoa hexadecimal float scanf and strtod (#1288) 2024-09-14 17:11:04 -07:00
tmpfile_test.c Apply clang-format update to repo (#1154) 2024-04-25 10:38:00 -07:00
ungetc_test.c flip et / noet in modelines 2023-12-07 22:17:11 -05:00
vappendf_test.c Run clang-format (#1197) 2024-06-01 16:30:43 -04:00
zipdir_test.c Remove .internal from more header filenames 2024-08-04 12:52:25 -07:00