diff options
Diffstat (limited to 'libgo/go/cmd/cgo/out.go')
| -rw-r--r-- | libgo/go/cmd/cgo/out.go | 53 |
1 files changed, 41 insertions, 12 deletions
diff --git a/libgo/go/cmd/cgo/out.go b/libgo/go/cmd/cgo/out.go index b469b5fe06a..3cf16f90f98 100644 --- a/libgo/go/cmd/cgo/out.go +++ b/libgo/go/cmd/cgo/out.go @@ -173,8 +173,18 @@ func (p *Package) writeDefs() { if *gccgo { fmt.Fprintf(fc, "extern byte *%s;\n", n.C) } else { - fmt.Fprintf(fm, "extern char %s[];\n", n.C) - fmt.Fprintf(fm, "void *_cgohack_%s = %s;\n\n", n.C, n.C) + // Force a reference to all symbols so that + // the external linker will add DT_NEEDED + // entries as needed on ELF systems. + // Treat function variables differently + // to avoid type confict errors from LTO + // (Link Time Optimization). + if n.Kind == "fpvar" { + fmt.Fprintf(fm, "extern void %s();\n", n.C) + } else { + fmt.Fprintf(fm, "extern char %s[];\n", n.C) + fmt.Fprintf(fm, "void *_cgohack_%s = %s;\n\n", n.C, n.C) + } fmt.Fprintf(fgo2, "//go:linkname __cgo_%s %s\n", n.C, n.C) fmt.Fprintf(fgo2, "//go:cgo_import_static %s\n", n.C) fmt.Fprintf(fgo2, "var __cgo_%s byte\n", n.C) @@ -1026,14 +1036,28 @@ func (p *Package) writeExports(fgo2, fm, fgcc, fgcch io.Writer) { } fmt.Fprintf(fgcc, "}\n") - // Build the wrapper function compiled by cmd/compile. - // This unpacks the argument struct above and calls the Go function. + // In internal linking mode, the Go linker sees both + // the C wrapper written above and the Go wrapper it + // references. Hence, export the C wrapper (e.g., for + // if we're building a shared object). The Go linker + // will resolve the C wrapper's reference to the Go + // wrapper without a separate export. fmt.Fprintf(fgo2, "//go:cgo_export_dynamic %s\n", exp.ExpName) + // cgo_export_static refers to a symbol by its linker + // name, so set the linker name of the Go wrapper. fmt.Fprintf(fgo2, "//go:linkname _cgoexp%s_%s _cgoexp%s_%s\n", cPrefix, exp.ExpName, cPrefix, exp.ExpName) + // In external linking mode, the Go linker sees the Go + // wrapper, but not the C wrapper. For this case, + // export the Go wrapper so the host linker can + // resolve the reference from the C wrapper to the Go + // wrapper. fmt.Fprintf(fgo2, "//go:cgo_export_static _cgoexp%s_%s\n", cPrefix, exp.ExpName) + + // Build the wrapper function compiled by cmd/compile. + // This unpacks the argument struct above and calls the Go function. fmt.Fprintf(fgo2, "func _cgoexp%s_%s(a *%s) {\n", cPrefix, exp.ExpName, gotype) - fmt.Fprintf(fm, "int _cgoexp%s_%s;\n", cPrefix, exp.ExpName) + fmt.Fprintf(fm, "void _cgoexp%s_%s(void* p){}\n", cPrefix, exp.ExpName) if gccResult != "void" { // Write results back to frame. @@ -1722,8 +1746,12 @@ typedef struct __go_open_array { struct __go_string __go_byte_array_to_string(const void* p, intgo len); struct __go_open_array __go_string_to_byte_array (struct __go_string str); +extern void runtime_throw(const char *); + const char *_cgoPREFIX_Cfunc_CString(struct __go_string s) { char *p = malloc(s.__length+1); + if(p == NULL) + runtime_throw("runtime: C malloc failed"); memmove(p, s.__data, s.__length); p[s.__length] = 0; return p; @@ -1731,6 +1759,8 @@ const char *_cgoPREFIX_Cfunc_CString(struct __go_string s) { void *_cgoPREFIX_Cfunc_CBytes(struct __go_open_array b) { char *p = malloc(b.__count); + if(p == NULL) + runtime_throw("runtime: C malloc failed"); memmove(p, b.__values, b.__count); return p; } @@ -1749,14 +1779,13 @@ Slice _cgoPREFIX_Cfunc_GoBytes(char *p, int32_t n) { return __go_string_to_byte_array(s); } -extern void runtime_throw(const char *); void *_cgoPREFIX_Cfunc__CMalloc(size_t n) { - void *p = malloc(n); - if(p == NULL && n == 0) - p = malloc(1); - if(p == NULL) - runtime_throw("runtime: C malloc failed"); - return p; + void *p = malloc(n); + if(p == NULL && n == 0) + p = malloc(1); + if(p == NULL) + runtime_throw("runtime: C malloc failed"); + return p; } struct __go_type_descriptor; |