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