funcdata.go

Documentation: cmd/internal/objabi

     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  package objabi
     6  
     7  // This file defines the IDs for PCDATA and FUNCDATA instructions
     8  // in Go binaries.
     9  //
    10  // These must agree with ../../../runtime/funcdata.h and
    11  // ../../../runtime/symtab.go.
    12  
    13  const (
    14  	PCDATA_UnsafePoint   = 0
    15  	PCDATA_StackMapIndex = 1
    16  	PCDATA_InlTreeIndex  = 2
    17  
    18  	FUNCDATA_ArgsPointerMaps    = 0
    19  	FUNCDATA_LocalsPointerMaps  = 1
    20  	FUNCDATA_StackObjects       = 2
    21  	FUNCDATA_InlTree            = 3
    22  	FUNCDATA_OpenCodedDeferInfo = 4
    23  
    24  	// ArgsSizeUnknown is set in Func.argsize to mark all functions
    25  	// whose argument size is unknown (C vararg functions, and
    26  	// assembly code without an explicit specification).
    27  	// This value is generated by the compiler, assembler, or linker.
    28  	ArgsSizeUnknown = -0x80000000
    29  )
    30  
    31  // Special PCDATA values.
    32  const (
    33  	// PCDATA_UnsafePoint values.
    34  	PCDATA_UnsafePointSafe   = -1 // Safe for async preemption
    35  	PCDATA_UnsafePointUnsafe = -2 // Unsafe for async preemption
    36  
    37  	// PCDATA_Restart1(2) apply on a sequence of instructions, within
    38  	// which if an async preemption happens, we should back off the PC
    39  	// to the start of the sequence when resuming.
    40  	// We need two so we can distinguish the start/end of the sequence
    41  	// in case that two sequences are next to each other.
    42  	PCDATA_Restart1 = -3
    43  	PCDATA_Restart2 = -4
    44  
    45  	// Like PCDATA_Restart1, but back to function entry if async preempted.
    46  	PCDATA_RestartAtEntry = -5
    47  )
    48
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