https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106554
Bug ID: 106554
Summary: -fstack-usage result too low for variadic function on
Arm
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: tim.schendekehl+gcc at egnite dot de
Target Milestone: ---
The following code contains a simple variadic function:
void f(const char *fmt, ...)
{
(void)fmt;
}
I have compiled it with the following command:
arm-none-eabi-gcc teststackusage.c -mcpu=cortex-m7 -mthumb -c -O0 -Wall -Wextra
-fstack-usage
GCC creates the file teststackusage.su with information about the stack usage:
teststackusage.c:1:6:f 4 static
It reports a stack usage of 4 bytes, but the disassembly looks like it should
be 20 bytes:
00000000 <f>:
0: b40f push {r0, r1, r2, r3}
2: b480 push {r7}
4: af00 add r7, sp, #0
6: bf00 nop
8: 46bd mov sp, r7
a: bc80 pop {r7}
c: b004 add sp, #16
e: 4770 bx lr
Information reported by arm-none-eabi-gcc -v:
Using built-in specs.
COLLECT_GCC=arm-none-eabi-gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/arm-none-eabi/12.1.0/lto-wrapper
Target: arm-none-eabi
Configured with: /build/arm-none-eabi-gcc/src/gcc-12.1.0/configure
--target=arm-none-eabi --prefix=/usr --with-sysroot=/usr/arm-none-eabi
--with-native-system-header-dir=/include --libexecdir=/usr/lib
--enable-languages=c,c++ --enable-plugins --disable-decimal-float
--disable-libffi --disable-libgomp --disable-libmudflap --disable-libquadmath
--disable-libssp --disable-libstdcxx-pch --disable-nls --disable-shared
--disable-threads --disable-tls --with-gnu-as --with-gnu-ld --with-system-zlib
--with-newlib --with-headers=/usr/arm-none-eabi/include
--with-python-dir=share/gcc-arm-none-eabi --with-gmp --with-mpfr --with-mpc
--with-isl --with-libelf --enable-gnu-indirect-function
--with-host-libstdcxx='-static-libgcc -Wl,-Bstatic,-lstdc++,-Bdynamic -lm'
--with-pkgversion='Arch Repository' --with-bugurl=https://bugs.archlinux.org/
--with-multilib-list=rmprofile
Thread model: single
Supported LTO compression algorithms: zlib zstd
gcc version 12.1.0 (Arch Repository)
Also tested with arm-linux-gnueabi-gcc 9.4.0-1ubuntu1~20.04.1 for Ubuntu 20.04
and arm-none-eabi-gcc 11.2.1 from https://developer.arm.com, which have the
same problem.
