From 14c9b3be770b4a59a4113783600b8d4b06f5ccd3 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 issue 909. LGTM=iant R=iant CC=golang-codereviews https://codereview.appspot.com/149770043 --- src/runtime/signals_plan9.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'src/runtime/signals_plan9.h') diff --git a/src/runtime/signals_plan9.h b/src/runtime/signals_plan9.h index 818f508cf..4ee8e542c 100644 --- a/src/runtime/signals_plan9.h +++ b/src/runtime/signals_plan9.h @@ -2,6 +2,8 @@ // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. +#include "textflag.h" + #define N SigNotify #define K SigKill #define T SigThrow @@ -16,6 +18,7 @@ // If you add entries to this table, you must respect the prefix ordering // and also update the constant values is os_plan9.h. +#pragma dataflag NOPTR SigTab runtime·sigtab[] = { // Traps that we cannot be recovered. T, "sys: trap: debug exception", -- cgit v1.2.1