src/cmd/compile/internal/gc/dwinl.go - go - Git at Google

 // Copyright 2017 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package gc

 import (
 	"cmd/internal/dwarf"
 	"cmd/internal/obj"
 	"cmd/internal/src"
 	"strings"
 )

 // To identify variables by original source position.
 type varPos struct {
 	DeclName string
 	DeclFile string
 	DeclLine uint
 	DeclCol  uint
 }

 // This is the main entry point for collection of raw material to
 // drive generation of DWARF "inlined subroutine" DIEs. See proposal
 // 22080 for more details and background info.
 func assembleInlines(fnsym *obj.LSym, dwVars []*dwarf.Var) dwarf.InlCalls {
 	var inlcalls dwarf.InlCalls

 	if Debug_gendwarfinl != 0 {
 		Ctxt.Logf("assembling DWARF inlined routine info for %v\n", fnsym.Name)
 	}

 	// This maps inline index (from Ctxt.InlTree) to index in inlcalls.Calls
 	imap := make(map[int]int)

 	// Walk progs to build up the InlCalls data structure
 	var prevpos src.XPos
 	for p := fnsym.Func().Text; p != nil; p = p.Link {
 		if p.Pos == prevpos {
 			continue
 		}
 		ii := posInlIndex(p.Pos)
 		if ii >= 0 {
 			insertInlCall(&inlcalls, ii, imap)
 		}
 		prevpos = p.Pos
 	}

 	// This is used to partition DWARF vars by inline index. Vars not
 	// produced by the inliner will wind up in the vmap[0] entry.
 	vmap := make(map[int32][]*dwarf.Var)

 	// Now walk the dwarf vars and partition them based on whether they
 	// were produced by the inliner (dwv.InlIndex > 0) or were original
 	// vars/params from the function (dwv.InlIndex == 0).
 	for _, dwv := range dwVars {

 		vmap[dwv.InlIndex] = append(vmap[dwv.InlIndex], dwv)

 		// Zero index => var was not produced by an inline
 		if dwv.InlIndex == 0 {
 			continue
 		}

 		// Look up index in our map, then tack the var in question
 		// onto the vars list for the correct inlined call.
 		ii := int(dwv.InlIndex) - 1
 		idx, ok := imap[ii]
 		if !ok {
 			// We can occasionally encounter a var produced by the
 			// inliner for which there is no remaining prog; add a new
 			// entry to the call list in this scenario.
 			idx = insertInlCall(&inlcalls, ii, imap)
 		}
 		inlcalls.Calls[idx].InlVars =
 			append(inlcalls.Calls[idx].InlVars, dwv)
 	}

 	// Post process the map above to assign child indices to vars.
 	//
 	// A given variable is treated differently depending on whether it
 	// is part of the top-level function (ii == 0) or if it was
 	// produced as a result of an inline (ii != 0).
 	//
 	// If a variable was not produced by an inline and its containing
 	// function was not inlined, then we just assign an ordering of
 	// based on variable name.
 	//
 	// If a variable was not produced by an inline and its containing
 	// function was inlined, then we need to assign a child index
 	// based on the order of vars in the abstract function (in
 	// addition, those vars that don't appear in the abstract
 	// function, such as "~r1", are flagged as such).
 	//
 	// If a variable was produced by an inline, then we locate it in
 	// the pre-inlining decls for the target function and assign child
 	// index accordingly.
 	for ii, sl := range vmap {
 		var m map[varPos]int
 		if ii == 0 {
 			if !fnsym.WasInlined() {
 				for j, v := range sl {
 					v.ChildIndex = int32(j)
 				}
 				continue
 			}
 			m = makePreinlineDclMap(fnsym)
 		} else {
 			ifnlsym := Ctxt.InlTree.InlinedFunction(int(ii - 1))
 			m = makePreinlineDclMap(ifnlsym)
 		}

 		// Here we assign child indices to variables based on
 		// pre-inlined decls, and set the "IsInAbstract" flag
 		// appropriately. In addition: parameter and local variable
 		// names are given "middle dot" version numbers as part of the
 		// writing them out to export data (see issue 4326). If DWARF
 		// inlined routine generation is turned on, we want to undo
 		// this versioning, since DWARF variables in question will be
 		// parented by the inlined routine and not the top-level
 		// caller.
 		synthCount := len(m)
 		for _, v := range sl {
 			canonName := unversion(v.Name)
 			vp := varPos{
 				DeclName: canonName,
 				DeclFile: v.DeclFile,
 				DeclLine: v.DeclLine,
 				DeclCol:  v.DeclCol,
 			}
 			synthesized := strings.HasPrefix(v.Name, "~r") || canonName == "_" || strings.HasPrefix(v.Name, "~b")
 			if idx, found := m[vp]; found {
 				v.ChildIndex = int32(idx)
 				v.IsInAbstract = !synthesized
 				v.Name = canonName
 			} else {
 				// Variable can't be found in the pre-inline dcl list.
 				// In the top-level case (ii=0) this can happen
 				// because a composite variable was split into pieces,
 				// and we're looking at a piece. We can also see
 				// return temps (~r%d) that were created during
 				// lowering, or unnamed params ("_").
 				v.ChildIndex = int32(synthCount)
 				synthCount++
 			}
 		}
 	}

 	// Make a second pass through the progs to compute PC ranges for
 	// the various inlined calls.
 	start := int64(-1)
 	curii := -1
 	var prevp *obj.Prog
 	for p := fnsym.Func().Text; p != nil; prevp, p = p, p.Link {
 		if prevp != nil && p.Pos == prevp.Pos {
 			continue
 		}
 		ii := posInlIndex(p.Pos)
 		if ii == curii {
 			continue
 		}
 		// Close out the current range
 		if start != -1 {
 			addRange(inlcalls.Calls, start, p.Pc, curii, imap)
 		}
 		// Begin new range
 		start = p.Pc
 		curii = ii
 	}
 	if start != -1 {
 		addRange(inlcalls.Calls, start, fnsym.Size, curii, imap)
 	}

 	// Debugging
 	if Debug_gendwarfinl != 0 {
 		dumpInlCalls(inlcalls)
 		dumpInlVars(dwVars)
 	}

 	return inlcalls
 }

 // Secondary hook for DWARF inlined subroutine generation. This is called
 // late in the compilation when it is determined that we need an
 // abstract function DIE for an inlined routine imported from a
 // previously compiled package.
 func genAbstractFunc(fn *obj.LSym) {
 	ifn := Ctxt.DwFixups.GetPrecursorFunc(fn)
 	if ifn == nil {
 		Ctxt.Diag("failed to locate precursor fn for %v", fn)
 		return
 	}
 	if Debug_gendwarfinl != 0 {
 		Ctxt.Logf("DwarfAbstractFunc(%v)\n", fn.Name)
 	}
 	Ctxt.DwarfAbstractFunc(ifn, fn, myimportpath)
 }

 // Undo any versioning performed when a name was written
 // out as part of export data.
 func unversion(name string) string {
 	if i := strings.Index(name, "·"); i > 0 {
 		name = name[:i]
 	}
 	return name
 }

 // Given a function that was inlined as part of the compilation, dig
 // up the pre-inlining DCL list for the function and create a map that
 // supports lookup of pre-inline dcl index, based on variable
 // position/name. NB: the recipe for computing variable pos/file/line
 // needs to be kept in sync with the similar code in gc.createSimpleVars
 // and related functions.
 func makePreinlineDclMap(fnsym *obj.LSym) map[varPos]int {
 	dcl := preInliningDcls(fnsym)
 	m := make(map[varPos]int)
 	for i, n := range dcl {
 		pos := Ctxt.InnermostPos(n.Pos)
 		vp := varPos{
 			DeclName: unversion(n.Sym.Name),
 			DeclFile: pos.RelFilename(),
 			DeclLine: pos.RelLine(),
 			DeclCol:  pos.Col(),
 		}
 		if _, found := m[vp]; found {
 			Fatalf("child dcl collision on symbol %s within %v\n", n.Sym.Name, fnsym.Name)
 		}
 		m[vp] = i
 	}
 	return m
 }

 func insertInlCall(dwcalls *dwarf.InlCalls, inlIdx int, imap map[int]int) int {
 	callIdx, found := imap[inlIdx]
 	if found {
 		return callIdx
 	}

 	// Haven't seen this inline yet. Visit parent of inline if there
 	// is one. We do this first so that parents appear before their
 	// children in the resulting table.
 	parCallIdx := -1
 	parInlIdx := Ctxt.InlTree.Parent(inlIdx)
 	if parInlIdx >= 0 {
 		parCallIdx = insertInlCall(dwcalls, parInlIdx, imap)
 	}

 	// Create new entry for this inline
 	inlinedFn := Ctxt.InlTree.InlinedFunction(inlIdx)
 	callXPos := Ctxt.InlTree.CallPos(inlIdx)
 	absFnSym := Ctxt.DwFixups.AbsFuncDwarfSym(inlinedFn)
 	pb := Ctxt.PosTable.Pos(callXPos).Base()
 	callFileSym := Ctxt.Lookup(pb.SymFilename())
 	ic := dwarf.InlCall{
 		InlIndex:  inlIdx,
 		CallFile:  callFileSym,
 		CallLine:  uint32(callXPos.Line()),
 		AbsFunSym: absFnSym,
 		Root:      parCallIdx == -1,
 	}
 	dwcalls.Calls = append(dwcalls.Calls, ic)
 	callIdx = len(dwcalls.Calls) - 1
 	imap[inlIdx] = callIdx

 	if parCallIdx != -1 {
 		// Add this inline to parent's child list
 		dwcalls.Calls[parCallIdx].Children = append(dwcalls.Calls[parCallIdx].Children, callIdx)
 	}

 	return callIdx
 }

 // Given a src.XPos, return its associated inlining index if it
 // corresponds to something created as a result of an inline, or -1 if
 // there is no inline info. Note that the index returned will refer to
 // the deepest call in the inlined stack, e.g. if you have "A calls B
 // calls C calls D" and all three callees are inlined (B, C, and D),
 // the index for a node from the inlined body of D will refer to the
 // call to D from C. Whew.
 func posInlIndex(xpos src.XPos) int {
 	pos := Ctxt.PosTable.Pos(xpos)
 	if b := pos.Base(); b != nil {
 		ii := b.InliningIndex()
 		if ii >= 0 {
 			return ii
 		}
 	}
 	return -1
 }

 func addRange(calls []dwarf.InlCall, start, end int64, ii int, imap map[int]int) {
 	if start == -1 {
 		panic("bad range start")
 	}
 	if end == -1 {
 		panic("bad range end")
 	}
 	if ii == -1 {
 		return
 	}
 	if start == end {
 		return
 	}
 	// Append range to correct inlined call
 	callIdx, found := imap[ii]
 	if !found {
 		Fatalf("can't find inlIndex %d in imap for prog at %d\n", ii, start)
 	}
 	call := &calls[callIdx]
 	call.Ranges = append(call.Ranges, dwarf.Range{Start: start, End: end})
 }

 func dumpInlCall(inlcalls dwarf.InlCalls, idx, ilevel int) {
 	for i := 0; i < ilevel; i++ {
 		Ctxt.Logf("  ")
 	}
 	ic := inlcalls.Calls[idx]
 	callee := Ctxt.InlTree.InlinedFunction(ic.InlIndex)
 	Ctxt.Logf("  %d: II:%d (%s) V: (", idx, ic.InlIndex, callee.Name)
 	for _, f := range ic.InlVars {
 		Ctxt.Logf(" %v", f.Name)
 	}
 	Ctxt.Logf(" ) C: (")
 	for _, k := range ic.Children {
 		Ctxt.Logf(" %v", k)
 	}
 	Ctxt.Logf(" ) R:")
 	for _, r := range ic.Ranges {
 		Ctxt.Logf(" [%d,%d)", r.Start, r.End)
 	}
 	Ctxt.Logf("\n")
 	for _, k := range ic.Children {
 		dumpInlCall(inlcalls, k, ilevel+1)
 	}

 }

 func dumpInlCalls(inlcalls dwarf.InlCalls) {
 	for k, c := range inlcalls.Calls {
 		if c.Root {
 			dumpInlCall(inlcalls, k, 0)
 		}
 	}
 }

 func dumpInlVars(dwvars []*dwarf.Var) {
 	for i, dwv := range dwvars {
 		typ := "local"
 		if dwv.Abbrev == dwarf.DW_ABRV_PARAM_LOCLIST || dwv.Abbrev == dwarf.DW_ABRV_PARAM {
 			typ = "param"
 		}
 		ia := 0
 		if dwv.IsInAbstract {
 			ia = 1
 		}
 		Ctxt.Logf("V%d: %s CI:%d II:%d IA:%d %s\n", i, dwv.Name, dwv.ChildIndex, dwv.InlIndex-1, ia, typ)
 	}
 }
	// Copyright 2017 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package gc

	import (
	"cmd/internal/dwarf"
	"cmd/internal/obj"
	"cmd/internal/src"
	"strings"
	)

	// To identify variables by original source position.
	type varPos struct {
	DeclName string
	DeclFile string
	DeclLine uint
	DeclCol uint
	}

	// This is the main entry point for collection of raw material to
	// drive generation of DWARF "inlined subroutine" DIEs. See proposal
	// 22080 for more details and background info.
	func assembleInlines(fnsym obj.LSym, dwVars []dwarf.Var) dwarf.InlCalls {
	var inlcalls dwarf.InlCalls

	if Debug_gendwarfinl != 0 {
	Ctxt.Logf("assembling DWARF inlined routine info for %v\n", fnsym.Name)
	}

	// This maps inline index (from Ctxt.InlTree) to index in inlcalls.Calls
	imap := make(map[int]int)

	// Walk progs to build up the InlCalls data structure
	var prevpos src.XPos
	for p := fnsym.Func().Text; p != nil; p = p.Link {
	if p.Pos == prevpos {
	continue
	}
	ii := posInlIndex(p.Pos)
	if ii >= 0 {
	insertInlCall(&inlcalls, ii, imap)
	}
	prevpos = p.Pos
	}

	// This is used to partition DWARF vars by inline index. Vars not
	// produced by the inliner will wind up in the vmap[0] entry.
	vmap := make(map[int32][]*dwarf.Var)

	// Now walk the dwarf vars and partition them based on whether they
	// were produced by the inliner (dwv.InlIndex > 0) or were original
	// vars/params from the function (dwv.InlIndex == 0).
	for _, dwv := range dwVars {

	vmap[dwv.InlIndex] = append(vmap[dwv.InlIndex], dwv)

	// Zero index => var was not produced by an inline
	if dwv.InlIndex == 0 {
	continue
	}

	// Look up index in our map, then tack the var in question
	// onto the vars list for the correct inlined call.
	ii := int(dwv.InlIndex) - 1
	idx, ok := imap[ii]
	if !ok {
	// We can occasionally encounter a var produced by the
	// inliner for which there is no remaining prog; add a new
	// entry to the call list in this scenario.
	idx = insertInlCall(&inlcalls, ii, imap)
	}
	inlcalls.Calls[idx].InlVars =
	append(inlcalls.Calls[idx].InlVars, dwv)
	}

	// Post process the map above to assign child indices to vars.
	//
	// A given variable is treated differently depending on whether it
	// is part of the top-level function (ii == 0) or if it was
	// produced as a result of an inline (ii != 0).
	//
	// If a variable was not produced by an inline and its containing
	// function was not inlined, then we just assign an ordering of
	// based on variable name.
	//
	// If a variable was not produced by an inline and its containing
	// function was inlined, then we need to assign a child index
	// based on the order of vars in the abstract function (in
	// addition, those vars that don't appear in the abstract
	// function, such as "~r1", are flagged as such).
	//
	// If a variable was produced by an inline, then we locate it in
	// the pre-inlining decls for the target function and assign child
	// index accordingly.
	for ii, sl := range vmap {
	var m map[varPos]int
	if ii == 0 {
	if !fnsym.WasInlined() {
	for j, v := range sl {
	v.ChildIndex = int32(j)
	}
	continue
	}
	m = makePreinlineDclMap(fnsym)
	} else {
	ifnlsym := Ctxt.InlTree.InlinedFunction(int(ii - 1))
	m = makePreinlineDclMap(ifnlsym)
	}

	// Here we assign child indices to variables based on
	// pre-inlined decls, and set the "IsInAbstract" flag
	// appropriately. In addition: parameter and local variable
	// names are given "middle dot" version numbers as part of the
	// writing them out to export data (see issue 4326). If DWARF
	// inlined routine generation is turned on, we want to undo
	// this versioning, since DWARF variables in question will be
	// parented by the inlined routine and not the top-level
	// caller.
	synthCount := len(m)
	for _, v := range sl {
	canonName := unversion(v.Name)
	vp := varPos{
	DeclName: canonName,
	DeclFile: v.DeclFile,
	DeclLine: v.DeclLine,
	DeclCol: v.DeclCol,
	}
	synthesized := strings.HasPrefix(v.Name, "~r") \|\| canonName == "_" \|\| strings.HasPrefix(v.Name, "~b")
	if idx, found := m[vp]; found {
	v.ChildIndex = int32(idx)
	v.IsInAbstract = !synthesized
	v.Name = canonName
	} else {
	// Variable can't be found in the pre-inline dcl list.
	// In the top-level case (ii=0) this can happen
	// because a composite variable was split into pieces,
	// and we're looking at a piece. We can also see
	// return temps (~r%d) that were created during
	// lowering, or unnamed params ("_").
	v.ChildIndex = int32(synthCount)
	synthCount++
	}
	}
	}

	// Make a second pass through the progs to compute PC ranges for
	// the various inlined calls.
	start := int64(-1)
	curii := -1
	var prevp *obj.Prog
	for p := fnsym.Func().Text; p != nil; prevp, p = p, p.Link {
	if prevp != nil && p.Pos == prevp.Pos {
	continue
	}
	ii := posInlIndex(p.Pos)
	if ii == curii {
	continue
	}
	// Close out the current range
	if start != -1 {
	addRange(inlcalls.Calls, start, p.Pc, curii, imap)
	}
	// Begin new range
	start = p.Pc
	curii = ii
	}
	if start != -1 {
	addRange(inlcalls.Calls, start, fnsym.Size, curii, imap)
	}

	// Debugging
	if Debug_gendwarfinl != 0 {
	dumpInlCalls(inlcalls)
	dumpInlVars(dwVars)
	}

	return inlcalls
	}

	// Secondary hook for DWARF inlined subroutine generation. This is called
	// late in the compilation when it is determined that we need an
	// abstract function DIE for an inlined routine imported from a
	// previously compiled package.
	func genAbstractFunc(fn *obj.LSym) {
	ifn := Ctxt.DwFixups.GetPrecursorFunc(fn)
	if ifn == nil {
	Ctxt.Diag("failed to locate precursor fn for %v", fn)
	return
	}
	if Debug_gendwarfinl != 0 {
	Ctxt.Logf("DwarfAbstractFunc(%v)\n", fn.Name)
	}
	Ctxt.DwarfAbstractFunc(ifn, fn, myimportpath)
	}

	// Undo any versioning performed when a name was written
	// out as part of export data.
	func unversion(name string) string {
	if i := strings.Index(name, "·"); i > 0 {
	name = name[:i]
	}
	return name
	}

	// Given a function that was inlined as part of the compilation, dig
	// up the pre-inlining DCL list for the function and create a map that
	// supports lookup of pre-inline dcl index, based on variable
	// position/name. NB: the recipe for computing variable pos/file/line
	// needs to be kept in sync with the similar code in gc.createSimpleVars
	// and related functions.
	func makePreinlineDclMap(fnsym *obj.LSym) map[varPos]int {
	dcl := preInliningDcls(fnsym)
	m := make(map[varPos]int)
	for i, n := range dcl {
	pos := Ctxt.InnermostPos(n.Pos)
	vp := varPos{
	DeclName: unversion(n.Sym.Name),
	DeclFile: pos.RelFilename(),
	DeclLine: pos.RelLine(),
	DeclCol: pos.Col(),
	}
	if _, found := m[vp]; found {
	Fatalf("child dcl collision on symbol %s within %v\n", n.Sym.Name, fnsym.Name)
	}
	m[vp] = i
	}
	return m
	}

	func insertInlCall(dwcalls *dwarf.InlCalls, inlIdx int, imap map[int]int) int {
	callIdx, found := imap[inlIdx]
	if found {
	return callIdx
	}

	// Haven't seen this inline yet. Visit parent of inline if there
	// is one. We do this first so that parents appear before their
	// children in the resulting table.
	parCallIdx := -1
	parInlIdx := Ctxt.InlTree.Parent(inlIdx)
	if parInlIdx >= 0 {
	parCallIdx = insertInlCall(dwcalls, parInlIdx, imap)
	}

	// Create new entry for this inline
	inlinedFn := Ctxt.InlTree.InlinedFunction(inlIdx)
	callXPos := Ctxt.InlTree.CallPos(inlIdx)
	absFnSym := Ctxt.DwFixups.AbsFuncDwarfSym(inlinedFn)
	pb := Ctxt.PosTable.Pos(callXPos).Base()
	callFileSym := Ctxt.Lookup(pb.SymFilename())
	ic := dwarf.InlCall{
	InlIndex: inlIdx,
	CallFile: callFileSym,
	CallLine: uint32(callXPos.Line()),
	AbsFunSym: absFnSym,
	Root: parCallIdx == -1,
	}
	dwcalls.Calls = append(dwcalls.Calls, ic)
	callIdx = len(dwcalls.Calls) - 1
	imap[inlIdx] = callIdx

	if parCallIdx != -1 {
	// Add this inline to parent's child list
	dwcalls.Calls[parCallIdx].Children = append(dwcalls.Calls[parCallIdx].Children, callIdx)
	}

	return callIdx
	}

	// Given a src.XPos, return its associated inlining index if it
	// corresponds to something created as a result of an inline, or -1 if
	// there is no inline info. Note that the index returned will refer to
	// the deepest call in the inlined stack, e.g. if you have "A calls B
	// calls C calls D" and all three callees are inlined (B, C, and D),
	// the index for a node from the inlined body of D will refer to the
	// call to D from C. Whew.
	func posInlIndex(xpos src.XPos) int {
	pos := Ctxt.PosTable.Pos(xpos)
	if b := pos.Base(); b != nil {
	ii := b.InliningIndex()
	if ii >= 0 {
	return ii
	}
	}
	return -1
	}

	func addRange(calls []dwarf.InlCall, start, end int64, ii int, imap map[int]int) {
	if start == -1 {
	panic("bad range start")
	}
	if end == -1 {
	panic("bad range end")
	}
	if ii == -1 {
	return
	}
	if start == end {
	return
	}
	// Append range to correct inlined call
	callIdx, found := imap[ii]
	if !found {
	Fatalf("can't find inlIndex %d in imap for prog at %d\n", ii, start)
	}
	call := &calls[callIdx]
	call.Ranges = append(call.Ranges, dwarf.Range{Start: start, End: end})
	}

	func dumpInlCall(inlcalls dwarf.InlCalls, idx, ilevel int) {
	for i := 0; i < ilevel; i++ {
	Ctxt.Logf(" ")
	}
	ic := inlcalls.Calls[idx]
	callee := Ctxt.InlTree.InlinedFunction(ic.InlIndex)
	Ctxt.Logf(" %d: II:%d (%s) V: (", idx, ic.InlIndex, callee.Name)
	for _, f := range ic.InlVars {
	Ctxt.Logf(" %v", f.Name)
	}
	Ctxt.Logf(" ) C: (")
	for _, k := range ic.Children {
	Ctxt.Logf(" %v", k)
	}
	Ctxt.Logf(" ) R:")
	for _, r := range ic.Ranges {
	Ctxt.Logf(" [%d,%d)", r.Start, r.End)
	}
	Ctxt.Logf("\n")
	for _, k := range ic.Children {
	dumpInlCall(inlcalls, k, ilevel+1)
	}

	}

	func dumpInlCalls(inlcalls dwarf.InlCalls) {
	for k, c := range inlcalls.Calls {
	if c.Root {
	dumpInlCall(inlcalls, k, 0)
	}
	}
	}

	func dumpInlVars(dwvars []*dwarf.Var) {
	for i, dwv := range dwvars {
	typ := "local"
	if dwv.Abbrev == dwarf.DW_ABRV_PARAM_LOCLIST \|\| dwv.Abbrev == dwarf.DW_ABRV_PARAM {
	typ = "param"
	}
	ia := 0
	if dwv.IsInAbstract {
	ia = 1
	}
	Ctxt.Logf("V%d: %s CI:%d II:%d IA:%d %s\n", i, dwv.Name, dwv.ChildIndex, dwv.InlIndex-1, ia, typ)
	}
	}