https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81840
Bug ID: 81840
Summary: Incorrect warning issued in arm-to-x86_64 cross
compilation
Product: gcc
Version: 7.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: bneumeier at gmail dot com
Target Milestone: ---
Created attachment 41985
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41985&action=edit
preprocessed source code that demonstrates the issue
I'm using GCC 7 to build an armv7 to x86_64 cross toolchain. gas compilation
fails with an incorrect warning when compiling tc-i386.c. I've pruned tc-i386.i
as much as I can while preserving the problematic behavior, but it is still
pretty long so I am compressing it.
Details:
gcc version 7.1.1 20170802 (GCC)
Target: armv7l-unknown-linux-gnueabihf
Configured with: /home/random/work/build/gcc-7.1.0/configure
--prefix=/home/random/hostcbl2 --with-local-prefix=/home/random/hostcbl2
--disable-multilib --disable-nls --enable-shared --enable-languages=c,c++
--enable-c99 --enable-long-long --enable-threads=posix
--with-gmp=/home/random/hostcbl2 --with-mpfr=/home/random/hostcbl2
--with-mpc=/home/random/hostcbl2 --with-isl=/home/random/hostcbl2
--with-float=hard
The compilation line that fails is:
armv7l-unknown-linux-gnueabihf-gcc -W -Wall -Werror -Wno-unused-function
-Wno-implicit-fallthrough -g -O2 -c -o tc-i386.o tc-i386.i
The compiler emits this output:
tc-i386.i: In function 'output_invalid':
tc-i386.i:13834:12: error: '%x' directive output may be truncated writing
between 1 and 8 bytes into a region of size 5 [-Werror=format-truncation=]
"(0x%x)", (unsigned char) c);
^~
tc-i386.i:13834:8: note: directive argument in the range [0, 2147483647]
"(0x%x)", (unsigned char) c);
^~~~~~~~
tc-i386.i:13833:5: note: 'snprintf' output between 6 and 13 bytes into a
destination of size 8
snprintf (output_invalid_buf, sizeof (output_invalid_buf),
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"(0x%x)", (unsigned char) c);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
