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go/src/pkg/runtime/mgc0.h
Elias Naur 44cf814d50 runtime, cmd/ld: make code more position-independent
Change the stack unwinding code to compensate for the dynamic
relocation of symbols.
Change the gc instruction GC_CALL to use a relative offset instead of
an absolute address.

R=golang-dev
CC=golang-dev
https://golang.org/cl/7248048
2013-02-01 11:24:49 -08:00

44 lines
1.6 KiB
C

// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Garbage collector (GC)
// GC instruction opcodes.
//
// The opcode of an instruction is followed by zero or more
// arguments to the instruction.
//
// Meaning of arguments:
// off Offset (in bytes) from the start of the current object
// objgc Pointer to GC info of an object
// objgcrel Offset to GC info of an object
// len Length of an array
// elemsize Size (in bytes) of an element
// size Size (in bytes)
enum {
GC_END, // End of object, loop or subroutine. Args: none
GC_PTR, // A typed pointer. Args: (off, objgc)
GC_APTR, // Pointer to an arbitrary object. Args: (off)
GC_ARRAY_START, // Start an array with a fixed length. Args: (off, len, elemsize)
GC_ARRAY_NEXT, // The next element of an array. Args: none
GC_CALL, // Call a subroutine. Args: (off, objgcrel)
GC_MAP_PTR, // Go map. Args: (off, MapType*)
GC_STRING, // Go string. Args: (off)
GC_EFACE, // interface{}. Args: (off)
GC_IFACE, // interface{...}. Args: (off)
GC_SLICE, // Go slice. Args: (off, objgc)
GC_REGION, // A region/part of the current object. Args: (off, size, objgc)
GC_NUM_INSTR, // Number of instruction opcodes
};
enum {
// Size of GC's fixed stack.
//
// The current GC implementation permits:
// - at most 1 stack allocation because of GC_CALL
// - at most GC_STACK_CAPACITY allocations because of GC_ARRAY_START
GC_STACK_CAPACITY = 8,
};