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Ayke van Laethem c08b2dfe06 wasm: add Boehm GC support
This adds support for `-gc=boehm` on `-target=wasip1` and `-target=wasm`
(in a browser or NodeJS). Notably it does *not* add Boehm GC support for
`-target=wasip2`, since that target doesn't have a real libc.
2025-06-13 14:42:23 +02:00

89 lines
2.4 KiB
Go

package builder
// The well-known conservative Boehm-Demers-Weiser GC.
// This file provides a way to compile this GC for use with TinyGo.
import (
"path/filepath"
"strings"
"github.com/tinygo-org/tinygo/goenv"
)
var BoehmGC = Library{
name: "bdwgc",
cflags: func(target, headerPath string) []string {
libdir := filepath.Join(goenv.Get("TINYGOROOT"), "lib/bdwgc")
flags := []string{
// use a modern environment
"-DUSE_MMAP", // mmap is available
"-DUSE_MUNMAP", // return memory to the OS using munmap
"-DGC_BUILTIN_ATOMIC", // use compiler intrinsics for atomic operations
"-DNO_EXECUTE_PERMISSION", // don't make the heap executable
// specific flags for TinyGo
"-DALL_INTERIOR_POINTERS", // scan interior pointers (needed for Go)
"-DIGNORE_DYNAMIC_LOADING", // we don't support dynamic loading at the moment
"-DNO_GETCONTEXT", // musl doesn't support getcontext()
"-DGC_DISABLE_INCREMENTAL", // don't mess with SIGSEGV and such
// Use a minimal environment.
"-DNO_MSGBOX_ON_ERROR", // don't call MessageBoxA on Windows
"-DDONT_USE_ATEXIT",
"-DNO_GETENV",
// Special flag to work around the lack of __data_start in ld.lld.
// TODO: try to fix this in LLVM/lld directly so we don't have to
// work around it anymore.
"-DGC_DONT_REGISTER_MAIN_STATIC_DATA",
// Do not scan the stack. We have our own mechanism to do this.
"-DSTACK_NOT_SCANNED",
// Assertions can be enabled while debugging GC issues.
//"-DGC_ASSERTIONS",
// We use our own way of dealing with threads (that is a bit hacky).
// See src/runtime/gc_boehm.go.
//"-DGC_THREADS",
//"-DTHREAD_LOCAL_ALLOC",
"-I" + libdir + "/include",
}
return flags
},
needsLibc: true,
sourceDir: func() string {
return filepath.Join(goenv.Get("TINYGOROOT"), "lib/bdwgc")
},
librarySources: func(target string, _ bool) ([]string, error) {
sources := []string{
"allchblk.c",
"alloc.c",
"blacklst.c",
"dbg_mlc.c",
"dyn_load.c",
"finalize.c",
"headers.c",
"mach_dep.c",
"malloc.c",
"mark.c",
"mark_rts.c",
"misc.c",
"new_hblk.c",
"obj_map.c",
"os_dep.c",
"reclaim.c",
}
if strings.Split(target, "-")[2] == "windows" {
// Due to how the linker on Windows works (that doesn't allow
// undefined functions), we need to include these extra files.
sources = append(sources,
"mallocx.c",
"ptr_chck.c",
)
}
return sources, nil
},
}