funcdata.h

Documentation: runtime

     1// Copyright 2013 The Go Authors. All rights reserved.
     2// Use of this source code is governed by a BSD-style
     3// license that can be found in the LICENSE file.
     4
     5// This file defines the IDs for PCDATA and FUNCDATA instructions
     6// in Go binaries. It is included by assembly sources, so it must
     7// be written using #defines.
     8//
     9// These must agree with internal/abi/symtab.go.
    10
    11#define PCDATA_UnsafePoint 0
    12#define PCDATA_StackMapIndex 1
    13#define PCDATA_InlTreeIndex 2
    14#define PCDATA_ArgLiveIndex 3
    15
    16#define FUNCDATA_ArgsPointerMaps 0 /* garbage collector blocks */
    17#define FUNCDATA_LocalsPointerMaps 1
    18#define FUNCDATA_StackObjects 2
    19#define FUNCDATA_InlTree 3
    20#define FUNCDATA_OpenCodedDeferInfo 4 /* info for func with open-coded defers */
    21#define FUNCDATA_ArgInfo 5
    22#define FUNCDATA_ArgLiveInfo 6
    23#define FUNCDATA_WrapInfo 7
    24
    25// Pseudo-assembly statements.
    26
    27// GO_ARGS, GO_RESULTS_INITIALIZED, and NO_LOCAL_POINTERS are macros
    28// that communicate to the runtime information about the location and liveness
    29// of pointers in an assembly function's arguments, results, and stack frame.
    30// This communication is only required in assembly functions that make calls
    31// to other functions that might be preempted or grow the stack.
    32// NOSPLIT functions that make no calls do not need to use these macros.
    33
    34// GO_ARGS indicates that the Go prototype for this assembly function
    35// defines the pointer map for the function's arguments.
    36// GO_ARGS should be the first instruction in a function that uses it.
    37// It can be omitted if there are no arguments at all.
    38// GO_ARGS is inserted implicitly by the assembler for any function
    39// whose package-qualified symbol name belongs to the current package;
    40// it is therefore usually not necessary to write explicitly.
    41#define GO_ARGS	FUNCDATA $FUNCDATA_ArgsPointerMaps, go_args_stackmap(SB)
    42
    43// GO_RESULTS_INITIALIZED indicates that the assembly function
    44// has initialized the stack space for its results and that those results
    45// should be considered live for the remainder of the function.
    46#define GO_RESULTS_INITIALIZED	PCDATA $PCDATA_StackMapIndex, $1
    47
    48// NO_LOCAL_POINTERS indicates that the assembly function stores
    49// no pointers to heap objects in its local stack variables.
    50#define NO_LOCAL_POINTERS	FUNCDATA $FUNCDATA_LocalsPointerMaps, no_pointers_stackmap(SB)
    51
    52// ArgsSizeUnknown is set in Func.argsize to mark all functions
    53// whose argument size is unknown (C vararg functions, and
    54// assembly code without an explicit specification).
    55// This value is generated by the compiler, assembler, or linker.
    56#define ArgsSizeUnknown 0x80000000
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