https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117365
Bug ID: 117365
Summary: Captured this lost after assignment to std::function
Product: gcc
Version: 6.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: Koen.Poppe at vandewiele dot com
Target Milestone: ---
Created attachment 59498
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=59498&action=edit
Preprocessed source of minimal example
When cross compiling to ARM: a lambda with "this" captured stored into an
std::function looses the by-value captured this which results in a segmentation
fault if that this pointer is used.
Minimal program (main.cpp, preprocessed source attached):
#include <functional>
#include <iostream>
#include <inttypes.h>
#define CHECK(cond) do { if (cond){ std::cout << __LINE__ << ": '" #cond "' = "
<< "ok" << std::endl; } else { std::cerr << __LINE__ << ": '" #cond "' FAILED!"
<< std::endl; return __LINE__; } } while(false)
struct Class
{
using Fun = std::function<Class*()>;
int testWrapped()
{
Fun fun;
CHECK(!fun);
std::cout << "this = " << reinterpret_cast<intptr_t>(this) <<
std::endl;
fun = [this]() -> Class* {
std::cout << "this captured in lambda = " <<
reinterpret_cast<intptr_t>(this) << std::endl;
return this;
};
CHECK(fun);
CHECK(fun() == this);
std::cout << "lambda returns" << reinterpret_cast<intptr_t>(fun());
return 0;
}
};
int main()
{
Class c;
return c.testWrapped();
}
Expected output of the attached program:
13: '!fun' = ok
this = 2127567732
19: 'fun' = ok
this captured in lambda = 2127567732
20: 'fun() == this' = ok
Actual output:
13: '!fun' = ok
this = 2127567732
19: 'fun' = ok
this captured in lambda = 135996
20: 'fun() == this' FAILED!
As this is compiling for an embedded target, I have not been able to run this
with a more recent version to check whether this is already fixed.
Output of gcc -v -save-temps:
compiling main.cpp
Using built-in specs.
COLLECT_GCC=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi/arm-poky-linux-gnueabi-g++
Target: arm-poky-linux-gnueabi
Configured with: ../../../../../../work-shared/gcc-6.2.0-r0/gcc-6.2.0/configure
--build=x86_64-linux --host=x86_64-pokysdk-linux
--target=arm-poky-linux-gnueabi
--prefix=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr
--exec_prefix=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr
--bindir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi
--sbindir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi
--libexecdir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/libexec/arm-poky-linux-gnueabi
--datadir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/share
--sysconfdir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/etc
--sharedstatedir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/com
--localstatedir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/var
--libdir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/lib/arm-poky-linux-gnueabi
--includedir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/include
--oldincludedir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/include
--infodir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/share/info
--mandir=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/share/man
--disable-silent-rules --disable-dependency-tracking
--with-libtool-sysroot=/tmp/work/tmp/sysroots/x86_64-nativesdk-pokysdk-linux
--with-gnu-ld --enable-shared --enable-languages=c,c++ --enable-threads=posix
--enable-multilib --enable-c99 --enable-long-long --enable-symvers=gnu
--enable-libstdcxx-pch --program-prefix=arm-poky-linux-gnueabi-
--without-local-prefix --enable-lto --enable-libssp --enable-libitm
--disable-bootstrap --disable-libmudflap --with-system-zlib
--with-linker-hash-style=gnu --enable-linker-build-id --with-ppl=no
--with-cloog=no --enable-checking=release --enable-cheaders=c_global
--without-isl --with-gxx-include-dir=/not/exist/usr/include/c++/6.2.0
--with-build-time-tools=/tmp/work/tmp/sysroots/x86_64-linux/usr/arm-poky-linux-gnueabi/bin
--with-sysroot=/not/exist
--with-build-sysroot=/tmp/work/tmp/sysroots/imx6sololcc
--without-long-double-128 --enable-poison-system-directories
--with-mpfr=/tmp/work/tmp/sysroots/x86_64-nativesdk-pokysdk-linux
--with-mpc=/tmp/work/tmp/sysroots/x86_64-nativesdk-pokysdk-linux --enable-nls
--enable-initfini-array --with-arch=armv7-a
Thread model: posix
gcc version 6.2.0 (GCC)
COLLECT_GCC_OPTIONS='--sysroot=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi'
'-march=armv7-a' '-mfpu=neon' '-mfloat-abi=hard' '-mcpu=cortex-a9' '-c' '-O2'
'-g' '-feliminate-unused-debug-types' '-Werror' '-fvisibility=hidden'
'-fvisibility-inlines-hidden' '-O2' '-v' '-save-temps' '-std=gnu++11' '-Wall'
'-Wextra' '-D' '_REENTRANT' '-fPIC' '-D' 'NDEBUG' '-D' '-I' '.' '-o' 'main.o'
'-shared-libgcc' '-mtls-dialect=gnu'
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/libexec/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/6.2.0/cc1plus
-E -quiet -v -I . -I tmp/release -isysroot
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi
-D_GNU_SOURCE -D _REENTRANT main.cpp -march=armv7-a -mfpu=neon -mfloat-abi=hard
-mcpu=cortex-a9 -mtls-dialect=gnu -std=gnu++11 -Werror -Wall -Wextra
-feliminate-unused-debug-types -fvisibility=hidden -fvisibility-inlines-hidden
-fPIC -g -fworking-directory -O2 -O2 -fpch-preprocess -o main.ii
ignoring nonexistent directory
"/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/local/include"
ignoring nonexistent directory
"/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/lib/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/6.2.0/../../../../../arm-poky-linux-gnueabi/include"
#include "..." search starts here:
#include <...> search starts here:
.
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/include/c++/6.2.0
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/include/c++/6.2.0/arm-poky-linux-gnueabi
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/include/c++/6.2.0/backward
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/lib/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/6.2.0/include
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/lib/gcc/arm-poky-linux-gnueabi/6.2.0/include
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/lib/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/6.2.0/include-fixed
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/include
End of search list.
COLLECT_GCC_OPTIONS='--sysroot=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi'
'-march=armv7-a' '-mfpu=neon' '-mfloat-abi=hard' '-mcpu=cortex-a9' '-c' '-O2'
'-g' '-feliminate-unused-debug-types' '-Werror' '-fvisibility=hidden'
'-fvisibility-inlines-hidden' '-O2' '-v' '-save-temps' '-std=gnu++11' '-Wall'
'-Wextra' '-D' '_REENTRANT' '-fPIC' '-I' '.' '-I' 'tmp/release' '-o'
'tmp/release/main.o' '-shared-libgcc' '-mtls-dialect=gnu'
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/libexec/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/6.2.0/cc1plus
-fpreprocessed main.ii -quiet -dumpbase main.cpp -march=armv7-a -mfpu=neon
-mfloat-abi=hard -mcpu=cortex-a9 -mtls-dialect=gnu -auxbase-strip
tmp/release/main.o -g -O2 -O2 -Werror -Wall -Wextra -std=gnu++11 -version
-feliminate-unused-debug-types -fvisibility=hidden -fvisibility-inlines-hidden
-fPIC -o main.s
GNU C++11 (GCC) version 6.2.0 (arm-poky-linux-gnueabi)
compiled by GNU C version 6.2.0, GMP version 6.1.1, MPFR version 3.1.4,
MPC version 1.0.3, isl version none
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
GNU C++11 (GCC) version 6.2.0 (arm-poky-linux-gnueabi)
compiled by GNU C version 6.2.0, GMP version 6.1.1, MPFR version 3.1.4,
MPC version 1.0.3, isl version none
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 22642f806ec0c662250f0cdd3c15f78b
COLLECT_GCC_OPTIONS='--sysroot=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi'
'-march=armv7-a' '-mfpu=neon' '-mfloat-abi=hard' '-mcpu=cortex-a9' '-c' '-O2'
'-g' '-feliminate-unused-debug-types' '-Werror' '-fvisibility=hidden'
'-fvisibility-inlines-hidden' '-O2' '-v' '-save-temps' '-std=gnu++11' '-Wall'
'-Wextra' '-D' '_REENTRANT' '-fPIC' '-I' '.' '-I' 'tmp/release' '-o'
'tmp/release/main.o' '-shared-libgcc' '-mtls-dialect=gnu'
/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/libexec/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/6.2.0/as
-v -I . -I tmp/release -march=armv7-a -mcpu=cortex-a9 -mfloat-abi=hard
-mfpu=neon -meabi=5 -o tmp/release/main.o main.s
GNU assembler version 2.27.0 (arm-poky-linux-gnueabi) using BFD version (GNU
Binutils) 2.27.0.20160806
COMPILER_PATH=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/libexec/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/6.2.0/:/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/libexec/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/6.2.0/:/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/libexec/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/:/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/lib/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/6.2.0/:/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/lib/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/
LIBRARY_PATH=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/x86_64-pokysdk-linux/usr/lib/arm-poky-linux-gnueabi/gcc/arm-poky-linux-gnueabi/6.2.0/:/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/lib/:/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/lib/arm-poky-linux-gnueabi/6.2.0/:/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi/usr/lib/
COLLECT_GCC_OPTIONS='--sysroot=/opt/fsl-imx-x11/4.9.11-1.0.0/sysroots/cortexa9hf-neon-poky-linux-gnueabi'
'-march=armv7-a' '-mfpu=neon' '-mfloat-abi=hard' '-mcpu=cortex-a9' '-c' '-O2'
'-g' '-feliminate-unused-debug-types' '-Werror' '-fvisibility=hidden'
'-fvisibility-inlines-hidden' '-O2' '-v' '-save-temps' '-std=gnu++11' '-Wall'
'-Wextra' '-D' '_REENTRANT' '-fPIC' '-I' '.' '-I' 'tmp/release' '-o'
'tmp/release/main.o' '-shared-libgcc' '-mtls-dialect=gnu'
