https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102115
Bug ID: 102115
Summary: symbol address eliminated by the xtensa size
optimization
Product: gcc
Version: 12.0
URL: https://github.com/earlephilhower/newlib-xtensa/issues
/19#issuecomment-903203750
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: me at jhdtl dot ru
Target Milestone: ---
Host: x86_64-w64-mingw32
Target: xtensa-lx106-elf
Build: x86_64-linux-gnu
Created attachment 51370
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51370&action=edit
Missing symbol example
.\x86_64-w64-mingw32.xtensa-lx106-elf-1757bed.210826\xtensa-lx106-elf\bin\xtensa-lx106-elf-gcc.exe
-v
Using built-in specs.
COLLECT_GCC=C:\Users\maxim\Documents\gist\a433474aa40ab0f6433f9240455fd624\x86_64-w64-mingw32.xtensa-lx106-elf-1757bed.210826\xtensa-lx106-elf\bin\xtensa-lx106-elf-gcc.exe
COLLECT_LTO_WRAPPER=c:/users/maxim/documents/gist/a433474aa40ab0f6433f9240455fd624/x86_64-w64-mingw32.xtensa-lx106-elf-1757bed.210826/xtensa-lx106-elf/bin/../libexec/gcc/xtensa-lx106-elf/12.0.0/lto-wrapper.exe
Target: xtensa-lx106-elf
Configured with: /home/jhdtl/dev/esp-quick-toolchain/repo/gcc-gnu/configure
--prefix=/home/jhdtl/dev/esp-quick-toolchain/xtensa-lx106-elf.win64
--build=x86_64-linux-gnu --host=x86_64-w64-mingw32 --target=xtensa-lx106-elf
--disable-shared --with-newlib --enable-threads=no --disable-__cxa_atexit
--disable-libgomp --disable-libmudflap --disable-nls --disable-multilib
--disable-bootstrap --enable-languages=c,c++ --enable-lto --enable-static=yes
--disable-libstdcxx-verbose
Thread model: single
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20210825 (experimental) (GCC)
After the 64a54505ec8249178b9767d1420354f8eb55de50, using -Os on
x86_64-w64-mingw32 *may* result in missing function symbol in the example
test.ii attached if the symbol's address can be compressed into small number
accepted by the movi + slli.
>From the URL, adding the suggested fprintf to the 'xtensa_emit_move_sequence'
and running with the following command:
$ xtensa-lx106-elf-g++.exe -Os -save-temps -mlongcalls -mtext-section-literals
-falign-functions=4 -ffunction-sections -fdata-sections -Wall
-Werror=return-type -free -fipa-pta -fno-rtti -std=gnu++17 -S -o test.S
test.cpp
Prints when the optimization happens:
[xtensa_emit_move_sequence @ function()] '513540096[0x1e9c0000]' =>
'1959[0x7a7] << 18'
[xtensa_emit_move_sequence @ function()] '513540096[0x1e9c0000]' =>
'1959[0x7a7] << 18'
[xtensa_emit_move_sequence @ function()] '513540096[0x1e9c0000]' =>
'1959[0x7a7] << 18'
Which will not be the expected function address at runtime, and will also
remove the symbol from the resulting object:
test.S:_Z8functionv:
movi a5, 0x7a7
slli a5, a5, 18
l32r a4, .LC209
l32r a2,
.LC426
mov.n a3, a5
s32i.n a5, sp, 20
call0 _Z8three132PFvPFvPFvvEES0_ES2_S0_
