execinfo.h is not available on MUSL

[radare]

V version:
OS:

What did you do?

try to build v for musl,

What did you expect to see?

a working build

What did you see instead?

a failure because the current ifndef is only for BIONIC

in fact execinfo is a gnuism, so it should be guarded like this:

#if (__linux__ && __GNU_LIBRARY__) || defined(NETBSD_WITH_BACKTRACE) || \
  defined(FREEBSD_WITH_BACKTRACE) || __DragonFly__
# include <execinfo.h>
#endif

[unknown-v]

alpineLinux has libexecinfo
don´t know about other musl based distros.

[radare]

[joe-conigliaro]

@radare Good point. Aldo the current backtrace implementation rely's on functions from it, we should have a minimal or different backtrace implementation when it isn't available (or no backtrace in that case)

[unknown-v]

@radare

Step 1/12 : FROM alpine:3.10.2
 ---> 961769676411
Step 2/12 : RUN         apk update apk upgrade &&       apk add --update gcc make       git musl-dev libexecinfo-dev    &&      mkdir -p 
/opt/v && cd /opt/v &&  git clone --quiet https://github.com/vlang/v .
 ---> Running in d45130455ecd
fetch https://dl-cdn.alpinelinux.org/alpine/v3.10/main/x86_64/APKINDEX.tar.gz
fetch https://dl-cdn.alpinelinux.org/alpine/v3.10/community/x86_64/APKINDEX.tar.gz
v3.10.2-189-g393dc02e8c [https://dl-cdn.alpinelinux.org/alpine/v3.10/main]
v3.10.2-189-g393dc02e8c [https://dl-cdn.alpinelinux.org/alpine/v3.10/community]
OK: 10337 distinct packages available
(1/20) Installing binutils (2.32-r0)
Step 3/12 : WORKDIR /opt/v
 ---> Running in 912eb8788caa
Removing intermediate container 912eb8788caa
 ---> 65d6a05e7ec2
Step 4/12 : RUN CC=gcc LDFLAGS=-lexecinfo make MAKE_VERBOSE=1
 ---> Running in 7b52a241035b
rm -rf vc/
git clone --depth 1 --quiet https://github.com/vlang/vc
rm -rf /var/tmp/tcc/
git clone --depth 1 --quiet https://github.com/vlang/tccbin /var/tmp/tcc
gcc -std=gnu11 -w -o v vc/v.c -lexecinfo -lm
rm -rf vc/
V has been successfully built
Removing intermediate container 7b52a241035b

[radare]

Ok i manage to compile it by adding the LDFLAGS=-lexecinfo env var but then it fails to do anything because:

• theres no way to add -lexecinfo when compiling with v (theres -cflags but not -ldflags)
• tcc fails hard. But using -cc gcc seems to work, is there a way to force this at compile time? May be better to fix tcc anyway

[radare]

[unknown-v]

tcc fails hard. But using -cc gcc seems to work, is there a way to force this at compile time?

export VFLAGS="-cc gcc"

[bogen85]

I got tcc to work by replacing what what was put in tmp.

$ cat /var/tmp/tcc/bin/tcc 
#!/usr/bin/env bash

tcc $@ -lexecinfo

What was put in tmp for tcc by the v update process did not work for me anyways on alpine.

[medvednikov]

@bogen85 so tcc works with musl with -lexecinfo?

[bogen85]

@medvednikov well, compiles and links on alpine with -lexecinfo... (and a lot works) but backtrace does not... See #2508

[comcloudway]

alpineLinux has libexecinfo don´t know about other musl based distros.

With Alpine Linux 3.17, they apparently removed libexecinfo-dev

• Search 3.16
• Search 3.17
• the given commit

Manually building and installing https://github.com/ronchaine/libexecinfo fixes the execinfo.h error though

[Brixy]

I just tried to compile V on chimera linux and got the following error:

clang -g -std=gnu11 -w -o v1 vc/v.c -lm -lexecinfo -lpthread 
ld: error: unable to find library -lexecinfo
clang: error: linker command failed with exit code 1 (use -v to see invocation)
*** Error code 1

After compiling and installing the libexecinfo library (repo has been archived!) the error message when compiling V changed to

cc -pipe -g -std=gnu11 -w -o v1 vc/v.c -lm -lexecinfo -lpthread 
./v1 -no-parallel -o v2 -cc gcc cmd/v
================== C compilation error (from gcc): ==============
cc: /tmp/v_1000/v2.01J4S9AQENEY9DHCEQC23JYGSS.tmp.c:21879:19: error: call to undeclared function 'backtrace'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
cc:  21879 |                                 int nr_ptrs = backtrace(&buffer[0], 100);
cc:        |                                               ^
cc: /tmp/v_1000/v2.01J4S9AQENEY9DHCEQC23JYGSS.tmp.c:21886:23: error: call to undeclared function 'backtrace_symbols'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
cc:  21886 |                                 char** csymbols = backtrace_symbols(((voidptr)(&buffer[v_fixed_index(skipframes, 100)])), nr_actual_frames);
cc:        |                                                   ^
cc: /tmp/v_1000/v2.01J4S9AQENEY9DHCEQC23JYGSS.tmp.c:21886:12: error: incompatible integer to pointer conversion initializing 'char **' with an expression of type 'int' [-Wint-conversion]
cc:  21886 |                                 char** csymbols = backtrace_symbols(((voidptr)(&buffer[v_fixed_index(skipframes, 100)])), nr_actual_frames);
cc:        |                                        ^          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
cc: /tmp/v_1000/v2.01J4S9AQENEY9DHCEQC23JYGSS.tmp.c:29920:4: warning: expression result unused [-Wunused-value]
cc:  29920 |   (*(string*)_t3.data);
cc:        |    ^~~~~~~~~~~~~~~~~~
... (the original output was 244 lines long, and was truncated to 12 lines)
=================================================================
(You can pass `-cg`, or `-show-c-output` as well, to print all the C error messages).
builder error: 
==================
C error found. It should never happen, when compiling pure V code.
This is a V compiler bug, please report it using `v bug file.v`,
or goto https://github.com/vlang/v/issues/new/choose .
You can also use #help on Discord: https://discord.gg/vlang .
*** Error code 1

Does anyone have any other ideas on how to get this to work reliably on a modern musl based distro? Thank you very much!

P.S.: Compiling V on alpine works.

[medvednikov]

I think we only tested musl builds on alpine.

execinfo is a common source of issues, would be best to avoid this dep.