github.com/phuslu/log@v1.0.100/runtime_go1.20.go (about)

     1  //go:build go1.20 && !go1.21
     2  // +build go1.20,!go1.21
     3  
     4  // MIT license, copy and modify from https://github.com/tlog-dev/loc
     5  
     6  //nolint:unused
     7  package log
     8  
     9  import (
    10  	"unsafe"
    11  )
    12  
    13  // inlinedCall is the encoding of entries in the FUNCDATA_InlTree table.
    14  type inlinedCall struct {
    15  	funcID    uint8 // type of the called function
    16  	_         [3]byte
    17  	nameOff   int32 // offset into pclntab for name of called function
    18  	parentPc  int32 // position of an instruction whose source position is the call site (offset from entry)
    19  	startLine int32 // line number of start of function (func keyword/TEXT directive)
    20  }
    21  
    22  func pcFileLineName(pc uintptr) (file string, line int32, name string) {
    23  	funcInfo := findfunc(pc)
    24  	if funcInfo._func == nil {
    25  		return
    26  	}
    27  
    28  	entry := funcInfoEntry(funcInfo)
    29  
    30  	if pc > entry {
    31  		// We store the pc of the start of the instruction following
    32  		// the instruction in question (the call or the inline mark).
    33  		// This is done for historical reasons, and to make FuncForPC
    34  		// work correctly for entries in the result of runtime.Callers.
    35  		pc--
    36  	}
    37  
    38  	file, line = funcline1(funcInfo, pc, false)
    39  
    40  	name = funcname(funcInfo)
    41  	const _PCDATA_InlTreeIndex = 2
    42  	const _FUNCDATA_InlTree = 3
    43  	if inldata := funcdata(funcInfo, _FUNCDATA_InlTree); inldata != nil {
    44  		inltree := (*[1 << 20]inlinedCall)(inldata)
    45  		// Non-strict as cgoTraceback may have added bogus PCs
    46  		// with a valid funcInfo but invalid PCDATA.
    47  		ix := pcdatavalue1(funcInfo, _PCDATA_InlTreeIndex, pc, nil, false)
    48  		if ix >= 0 {
    49  			// Note: entry is not modified. It always refers to a real frame, not an inlined one.
    50  			ic := inltree[ix]
    51  			name = funcnameFromNameOff(funcInfo, ic.nameOff)
    52  			// File/line from funcline1 below are already correct.
    53  		}
    54  	}
    55  
    56  	return
    57  }
    58  
    59  //go:linkname funcname runtime.funcname
    60  func funcname(f funcInfo) string
    61  
    62  //go:linkname funcdata runtime.funcdata
    63  func funcdata(f funcInfo, i uint8) unsafe.Pointer
    64  
    65  //go:linkname pcdatavalue1 runtime.pcdatavalue1
    66  func pcdatavalue1(f funcInfo, table int32, targetpc uintptr, cache unsafe.Pointer, strict bool) int32
    67  
    68  //go:linkname funcnameFromNameOff runtime.funcnameFromNameOff
    69  func funcnameFromNameOff(f funcInfo, nameoff int32) string
    70  
    71  // Fastrandn returns a pseudorandom uint32 in [0,n).
    72  //
    73  //go:noescape
    74  //go:linkname Fastrandn runtime.fastrandn
    75  func Fastrandn(x uint32) uint32