https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61666
Bug ID: 61666
Summary: go float32/64 to int64 conversion segfaults on mips32
when libgcc_cv_mips_hard_float=yes
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libgcc
Assignee: unassigned at gcc dot gnu.org
Reporter: eswierk at gmail dot com
Created attachment 33042
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33042&action=edit
Test case
I'm using gccgo 4.9.0 to cross-compile (for mips32 target) a Go program that
converts a float32 or float64 to an int64. When I run the program on a Cavium
Octeon2 target, the program segfaults when it reaches the conversion (the third
Println in the attached test case).
The problem appears to be related to
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=207593 .
I rebuilt gccgo, hacking libgcc/configure so that libgcc_cv_mips_hard_float=no.
With I recompile my program with the modified gccgo, it runs fine.
$ mips-linux-gnu-gccgo -v -g -o blerg blerg.go
Using built-in specs.
COLLECT_GCC=mips-linux-gnu-gccgo
COLLECT_LTO_WRAPPER=/usr/lib/gcc-cross/mips-linux-gnu/4.9/lto-wrapper
Target: mips-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 4.9.0-9-1blerg1'
--with-bugurl=file:///usr/share/doc/gcc-4.9/README.Bugs
--enable-languages=c,c++,java,go,d,fortran,objc,obj-c++ --prefix=/usr
--program-suffix=-4.9 --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--with-gxx-in\
clude-dir=/usr/mips-linux-gnu/include/c++/4.9.0 --libdir=/usr/lib --enable-nls
--enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes
--enable-gnu-unique-object --disable-libmudflap --disable-libitm
--disable-libsanitizer --disable-libquadmath --enable-plugin --with-system-zlib
--disable-browser-plugin --enable-java-awt=gtk --enable-\
gtk-cairo --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-4.9-mips-cross/jre
--enable-java-home
--with-jvm-root-dir=/usr/lib/jvm/java-1.5.0-gcj-4.9-mips-cross
--with-jvm-jar-dir=/usr/lib/jvm-exports/java-1.5.0-gcj-4.9-mips-cross
--with-arch-directory=mips --with-ecj-jar=/usr/share/java/eclipse-ecj.jar
--disable-libgcj --enable-multiarch --with-arch-32=mip\
s2 --with-tune-32=mips32 --enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=mips-linux-gnu
--program-prefix=mips-linux-gnu- --includedir=/usr/mips-linux-gnu/include
Thread model: posix
gcc version 4.9.0 (Debian 4.9.0-9-1blerg1)
COLLECT_GCC_OPTIONS='-v' '-g' '-o' 'blerg' '-shared-libgcc' '-march=mips2'
'-mtune=mips32' '-mllsc' '-mno-shared'
/usr/lib/gcc-cross/mips-linux-gnu/4.9/go1 blerg.go -quiet -dumpbase blerg.go
-march=mips2 -mtune=mips32 -mllsc -mno-shared -auxbase blerg -g -version
-L/usr/lib/gcc-cross/mips-linux-gnu/4.9
-L/usr/lib/gcc-cross/mips-linux-gnu/4.9/../../../../mips-linux-gnu/lib -o
/tmp/ccYmAhFL.s
GNU Go (Debian 4.9.0-9-1blerg1) version 4.9.0 (mips-linux-gnu)
compiled by GNU C version 4.9.0, GMP version 6.0.0, MPFR version
3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU Go (Debian 4.9.0-9-1blerg1) version 4.9.0 (mips-linux-gnu)
compiled by GNU C version 4.9.0, GMP version 6.0.0, MPFR version
3.1.2-p3, MPC version 1.0.1
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
COLLECT_GCC_OPTIONS='-v' '-g' '-o' 'blerg' '-shared-libgcc' '-march=mips2'
'-mtune=mips32' '-mllsc' '-mno-shared'
/usr/lib/gcc-cross/mips-linux-gnu/4.9/../../../../mips-linux-gnu/bin/as -v -EB
-O1 -g -no-mdebug -mabi=32 -march=mips2 -mno-shared -mtune=mips32
-mfix-loongson2f-nop -KPIC -o /tmp/ccpszM3o.o /tmp/ccYmAhFL.s
GNU assembler version 2.24.51 (mips-linux-gnu) using BFD version (GNU Binutils
for Debian) 2.24.51.20140425
COMPILER_PATH=/usr/lib/gcc-cross/mips-linux-gnu/4.9/:/usr/lib/gcc-cross/mips-linux-gnu/4.9/:/usr/lib/gcc-cross/mips-linux-gnu/:/usr/lib/gcc-cross/mips-linux-gnu/4.9/:/usr/lib/gcc-cross/mips-linux-gnu/:/usr/lib/gcc-cross/mips-linux-gnu/4.9/../../../../mips-linux-gnu/bin/
LIBRARY_PATH=/usr/lib/gcc-cross/mips-linux-gnu/4.9/:/usr/lib/gcc-cross/mips-linux-gnu/4.9/../../../../mips-linux-gnu/lib/
COLLECT_GCC_OPTIONS='-v' '-g' '-o' 'blerg' '-shared-libgcc' '-march=mips2'
'-mtune=mips32' '-mllsc' '-mno-shared'
/usr/lib/gcc-cross/mips-linux-gnu/4.9/collect2 -plugin
/usr/lib/gcc-cross/mips-linux-gnu/4.9/liblto_plugin.so
-plugin-opt=/usr/lib/gcc-cross/mips-linux-gnu/4.9/lto-wrapper
-plugin-opt=-fresolution=/tmp/cczxCGt2.res -plugin-opt=-pass-through=-lgcc_s
-plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lc
-plugin-opt=-pass-through=-lgcc_s -plugin-\
opt=-pass-through=-lgcc --build-id --eh-frame-hdr -EB -dynamic-linker
/lib/ld.so.1 -o blerg
/usr/lib/gcc-cross/mips-linux-gnu/4.9/../../../../mips-linux-gnu/lib/crt1.o
/usr/lib/gcc-cross/mips-linux-gnu/4.9/../../../../mips-linux-gnu/lib/crti.o
/usr/lib/gcc-cross/mips-linux-gnu/4.9/crtbegin.o
-L/usr/lib/gcc-cross/mips-linux-gnu/4.9 -L/usr/lib/gcc-cross/\
mips-linux-gnu/4.9/../../../../mips-linux-gnu/lib /tmp/ccpszM3o.o -lgobegin
-lgo -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc
/usr/lib/gcc-cross/mips-linux-gnu/4.9/crtend.o
/usr/lib/gcc-cross/mips-linux-gnu/4.9/../../../../mips-linux-gnu/lib/crtn.o
with unmodified gccgo:
$ ./blerg
f32 = 2.22e+11
int32(f32) = 2147483647
unexpected fault address 0x4eb8ce18
fatal error: fault
[signal 0xb code=0x2 addr=0x4eb8ce18]
goroutine 1 [running]:
:0
:0
:0
:0
:0
with modified gccgo:
$ ./blerg
f32 = 2.22e+11
int32(f32) = 2147483647
int64(f32) = 222000005120
f64 = 2.22e+11
int32(f46) = 2147483647
int64(f64) = 222000000000
blerg.go:
package main
import "fmt"
func main() {
var f32 float32 = 2.22e+11
fmt.Println("f32 =", f32)
fmt.Println("int32(f32) =", int32(f32))
fmt.Println("int64(f32) =", int64(f32))
var f64 float64 = 2.22e+11
fmt.Println("f64 =", f64)
fmt.Println("int32(f46) =", int32(f64))
fmt.Println("int64(f64) =", int64(f64))
}
