From 193daab9889708f7a20ff46efe0fa4b2bf0468d3 Mon Sep 17 00:00:00 2001 From: Russ Cox Date: Wed, 24 Sep 2014 16:55:26 -0400 Subject: cmd/cc, cmd/ld, runtime: disallow conservative data/bss objects In linker, refuse to write conservative (array of pointers) as the garbage collection type for any variable in the data/bss GC program. In the linker, attach the Go type to an already-read C declaration during dedup. This gives us Go types for C globals for free as long as the cmd/dist-generated Go code contains the declaration. (Most runtime C declarations have a corresponding Go declaration. Both are bss declarations and so the linker dedups them.) In cmd/dist, add a few more C files to the auto-Go-declaration list in order to get Go type information for the C declarations into the linker. In C compiler, mark all non-pointer-containing global declarations and all string data as NOPTR. This allows them to exist in C files without any corresponding Go declaration. Count C function pointers as "non-pointer-containing", since we have no heap-allocated C functions. In runtime, add NOPTR to the remaining pointer-containing declarations, none of which refer to Go heap objects. In runtime, also move os.Args and syscall.envs data into runtime-owned variables. Otherwise, in programs that do not import os or syscall, the runtime variables named os.Args and syscall.envs will be missing type information. I believe that this CL eliminates the final source of conservative GC scanning in non-SWIG Go programs, and therefore... Fixes #909. LGTM=iant R=iant CC=golang-codereviews https://golang.org/cl/149770043 --- src/runtime/runtime.go | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'src/runtime/runtime.go') diff --git a/src/runtime/runtime.go b/src/runtime/runtime.go index dbaea45a66..4e4e1d17a5 100644 --- a/src/runtime/runtime.go +++ b/src/runtime/runtime.go @@ -9,6 +9,8 @@ var ticks struct { val uint64 } +var tls0 [8]uintptr // available storage for m0's TLS; not necessarily used; opaque to GC + // Note: Called by runtime/pprof in addition to runtime code. func tickspersecond() int64 { r := int64(atomicload64(&ticks.val)) @@ -47,3 +49,12 @@ func parforalloc(nthrmax uint32) *parfor { nthrmax: nthrmax, } } + +var envs []string +var argslice []string + +// called from syscall +func runtime_envs() []string { return envs } + +// called from os +func runtime_args() []string { return argslice } -- cgit v1.3