http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47192
Summary: m68k target - gcc uses stack frame after it has been
unlinked when compiling with -Os
Product: gcc
Version: 4.5.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: t...@ls83.eclipse.co.uk
Created attachment 22913
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22913
Testcase - Preprocessor output
Attached test case produces code which ends with
61 003c 41EE FFFE lea (-2,%fp),%a0
30:gcc-bug.c **** return d;
31:gcc-bug.c **** }
62 .loc 1 32 0
63 0040 242E FFF8 move.l -8(%fp),%d2
64 0044 4E5E unlk %fp
30:gcc-bug.c **** return d;
65 .loc 1 30 0
66 0046 33D0 0000 move.w (%a0),stc.1197
66 0000
67 .loc 1 32 0
68 004c 4E75 rts
If an interrupt occurs between the unlk and move.w, the variable pointed to by
(a0) is corrupted prior to being copied.
Compiling with -O1 keeps the lea and move.w together before the unlk, which is
correct.
Compiling with -O2 results in a move.w d1,stc.1197 after the unlk (contents of
variable already in d1), so gets away with it.
gcc output below and .i file attached.
Problem also present in 4.5.1.
m68k-elf-gcc -v -save-temps -c -g -gdwarf-2 -ffunction-sections -fdata-sections
-Os -mcpu=51qe -Wall -Wa,-ahlms=gcc-bug.ls -I.
-I/usr/local/gcc-m68k/m68k-elf/include gcc-bug.c
Using built-in specs.
COLLECT_GCC=m68k-elf-gcc
COLLECT_LTO_WRAPPER=/usr/local/gcc-m68k-4.5.2/libexec/gcc/m68k-elf/4.5.2/lto-wrapper
Target: m68k-elf
Configured with: ../configure --target=m68k-elf
--prefix=/usr/local/gcc-m68k-4.5.2 --enable-languages=c --with-newlib
--disable-libssp --with-gnu-as --with-gnu-ld
Thread model: single
gcc version 4.5.2 (GCC)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-c' '-g' '-gdwarf-2'
'-ffunction-sections' '-fdata-sections' '-Os' '-mcpu=51qe' '-Wall' '-I.'
'-I/usr/local/gcc-m68k/m68k-elf/include'
/usr/local/gcc-m68k-4.5.2/libexec/gcc/m68k-elf/4.5.2/cc1 -E -quiet -v -I.
-I/usr/local/gcc-m68k/m68k-elf/include -imultilib m51qe gcc-bug.c -mcpu=51qe
-Wall -ffunction-sections -fdata-sections -g -gdwarf-2 -fworking-directory -Os
-fpch-preprocess -o gcc-bug.i
ignoring nonexistent directory
"/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/../../../../m68k-elf/sys-include"
#include "..." search starts here:
#include <...> search starts here:
.
/usr/local/gcc-m68k/m68k-elf/include
/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/include
/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/include-fixed
/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/../../../../m68k-elf/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-c' '-g' '-gdwarf-2'
'-ffunction-sections' '-fdata-sections' '-Os' '-mcpu=51qe' '-Wall' '-I.'
'-I/usr/local/gcc-m68k/m68k-elf/include'
/usr/local/gcc-m68k-4.5.2/libexec/gcc/m68k-elf/4.5.2/cc1 -fpreprocessed
gcc-bug.i -quiet -dumpbase gcc-bug.c -mcpu=51qe -auxbase gcc-bug -g -gdwarf-2
-Os -Wall -version -ffunction-sections -fdata-sections -o gcc-bug.s
GNU C (GCC) version 4.5.2 (m68k-elf)
compiled by GNU C version 4.3.2, GMP version 4.2.2, MPFR version 2.3.1, MPC
version 0.8.2
GGC heuristics: --param ggc-min-expand=64 --param ggc-min-heapsize=64520
GNU C (GCC) version 4.5.2 (m68k-elf)
compiled by GNU C version 4.3.2, GMP version 4.2.2, MPFR version 2.3.1, MPC
version 0.8.2
GGC heuristics: --param ggc-min-expand=64 --param ggc-min-heapsize=64520
Compiler executable checksum: 2edb184913810d520b23104a9f78d5ce
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-c' '-g' '-gdwarf-2'
'-ffunction-sections' '-fdata-sections' '-Os' '-mcpu=51qe' '-Wall' '-I.'
'-I/usr/local/gcc-m68k/m68k-elf/include'
/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/../../../../m68k-elf/bin/as
-v -I. -I/usr/local/gcc-m68k/m68k-elf/include -mcpu=51qe -ahlms=gcc-bug.ls -o
gcc-bug.o gcc-bug.s
GNU assembler version 2.20 (m68k-elf) using BFD version (GNU Binutils) 2.20
COMPILER_PATH=/usr/local/gcc-m68k-4.5.2/libexec/gcc/m68k-elf/4.5.2/:/usr/local/gcc-m68k-4.5.2/libexec/gcc/m68k-elf/4.5.2/:/usr/local/gcc-m68k-4.5.2/libexec/gcc/m68k-elf/:/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/:/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/:/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/../../../../m68k-elf/bin/
LIBRARY_PATH=/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/m51qe/:/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/../../../../m68k-elf/lib/m51qe/:/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/:/usr/local/gcc-m68k-4.5.2/lib/gcc/m68k-elf/4.5.2/../../../../m68k-elf/lib/
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-c' '-g' '-gdwarf-2'
'-ffunction-sections' '-fdata-sections' '-Os' '-mcpu=51qe' '-Wall' '-I.'
'-I/usr/local/gcc-m68k/m68k-elf/include'
