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, runtime·no_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