Text file src/runtime/funcdata.h

     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 symtab.go and ../cmd/internal/objabi/funcdata.go.
    10	
    11	#define PCDATA_RegMapIndex 0
    12	#define PCDATA_StackMapIndex 1
    13	#define PCDATA_InlTreeIndex 2
    14	
    15	#define FUNCDATA_ArgsPointerMaps 0 /* garbage collector blocks */
    16	#define FUNCDATA_LocalsPointerMaps 1
    17	#define FUNCDATA_RegPointerMaps 2
    18	#define FUNCDATA_StackObjects 3
    19	#define FUNCDATA_InlTree 4
    20	
    21	// Pseudo-assembly statements.
    22	
    23	// GO_ARGS, GO_RESULTS_INITIALIZED, and NO_LOCAL_POINTERS are macros
    24	// that communicate to the runtime information about the location and liveness
    25	// of pointers in an assembly function's arguments, results, and stack frame.
    26	// This communication is only required in assembly functions that make calls
    27	// to other functions that might be preempted or grow the stack.
    28	// NOSPLIT functions that make no calls do not need to use these macros.
    29	
    30	// GO_ARGS indicates that the Go prototype for this assembly function
    31	// defines the pointer map for the function's arguments.
    32	// GO_ARGS should be the first instruction in a function that uses it.
    33	// It can be omitted if there are no arguments at all.
    34	// GO_ARGS is inserted implicitly by the linker for any function
    35	// that also has a Go prototype and therefore is usually not necessary
    36	// to write explicitly.
    37	#define GO_ARGS	FUNCDATA $FUNCDATA_ArgsPointerMaps, go_args_stackmap(SB)
    38	
    39	// GO_RESULTS_INITIALIZED indicates that the assembly function
    40	// has initialized the stack space for its results and that those results
    41	// should be considered live for the remainder of the function.
    42	#define GO_RESULTS_INITIALIZED	PCDATA $PCDATA_StackMapIndex, $1
    43	
    44	// NO_LOCAL_POINTERS indicates that the assembly function stores
    45	// no pointers to heap objects in its local stack variables.
    46	#define NO_LOCAL_POINTERS	FUNCDATA $FUNCDATA_LocalsPointerMaps, runtime·no_pointers_stackmap(SB)
    47	
    48	// ArgsSizeUnknown is set in Func.argsize to mark all functions
    49	// whose argument size is unknown (C vararg functions, and
    50	// assembly code without an explicit specification).
    51	// This value is generated by the compiler, assembler, or linker.
    52	#define ArgsSizeUnknown 0x80000000

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