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