Build failure on powerpc: error: static assertion failed: "size", error: destructor priorities are not supported

[barracuda156]

@alexveden Could you please take a look? This is on 32-bit powerpc (Big-endian, of course):

Executing:  cd "/opt/local/var/macports/build/cex-9d7b774d/work" && /usr/bin/gzip -dc '/opt/local/var/macports/distfiles/cex/cex-0.16.0.tar.gz' | /usr/bin/gnutar --no-same-owner -xf - 
--->  Configuring cex
--->  Building cex
In file included from ./cex.h:97,
                 from ./cex.c:8:
./cex.h:730:1: error: static assertion failed: "size"
  730 | static_assert(sizeof((Allocator_i){ 0 }.meta) == 8, "size");
      | ^~~~~~~~~~~~~
./cex.h:5764:1: error: destructor priorities are not supported
 5764 | {
      | ^
Command failed: /opt/local/bin/gcc-mp-14 -isystem/opt/local/include/LegacySupport -I/opt/local/include -Wl,-headerpad_max_install_names -L/opt/local/lib -lMacportsLegacySupport ./cex.c -o cex

[alexveden]

Hi, I've checked and this assertion is not critical for functionality, just an early sanity check for possible issues when the code possibly used on rare architectures. Unfortunately, I don't have access to this arch via GH actions, and I would not be able to test it.

So I could only suggest to try to comment this line, and go ahead, run CEX tests and etc. Maybe there are some other assertions down the code. Generally speaking CEX was tested on 32-bit and big-endian, but it always depends on specific arch.

[barracuda156]

Thank you! And what about destructor priorities error? I vaguely recall it could be gcc specifics, but not sure.

[alexveden]

hm, destructors might be a problem, this line is related to automatic resource deallocation for global temporary allocator tmem$. It's useful stuff but not critical: you can try to use simple destructor without 101, or just comment out this function because all of the allocated memory will be deallocated anyway at the program end. This may trigger valgrind though.

// file: cex.h:5764
__attribute__((destructor(101))) void
_cex_global_allocators_destructor()
{
}

[barracuda156]

@alexveden Ah, I have found the related issue: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119435
It is not arch-specific, but relevant for macOS in general.

[barracuda156]

@alexveden Okay, so assert fails because this structure uses bools:

cex/cex.h

Lines 720 to 725 in b2f1d64

	struct {
	u32 magic_id;
	bool is_arena;
	bool is_temp;
	} meta;
	//<<< 64 byte cacheline

It should probably use u8 instead, and then we get expected size. Bool is 4 byte in ppc ABI.

With that and fixed destructor the build works.

Rebuilding itself fails, though, since it uses cc instead of the compiler used for the build. How can I adjust that? It will also likely need the same flags to compile successfully (for clock_gettime, which is provided via external library).
Update. I have found the config for that, I guess.

[alexveden]

It should probably use u8 instead, and then we get expected size. Bool is 4 byte in ppc ABI.
Good to know, try to disable this assert it should not lead to misbehavior.

There is a workaround if you need to use special compiler command, this is for mingw32 example #define cexy$cc "x86_64-w64-mingw32-gcc". You may try to use cex_config.h see the example in the repo.

It will also likely need the same flags to compile successfully (for clock_gettime, which is provided via external library).

These are build system flags defs for self + app/tests build:

#    define cexy$cex_self_args "-O2"
#    define cexy$cc_args "-Wall", "-Wextra", "-Werror", "-g", "-O3"

[barracuda156]

Looks like passing cflags/cppflags via cexy$cc_args works, but not ldflags. Is there a specific way to pass a flag to the linker? I need to link the executable with the specific library, otherwise symbols won’t be found.

[barracuda156]

Good to know, try to disable this assert it should not lead to misbehavior.

Is it better to disable assert, leaving bools, or just fix types in the structure (and keep the assert in place)? This works fine (i.e. no failing assert then):

 struct { 
     u32 magic_id; 
     u8 is_arena; 
     u8 is_temp; 
 } meta; 

[alexveden]

There is , but I'm not sure that it's applied to ./cex itself.

/// Linker flags (e.g. -L./lib/path/ -lmylib -lm) (may be overridden)
#define cexy$ld_args

Just disable failing assert first, it looks like it redundant in current case.

[alexveden]

You can get all available flags help by calling ./cex help cexy$