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cmd/compile: mark DIEs of captured variables
Adds a new custom attribute to the DIE of captured variables,
containing the offset for the variable inside the closure struct. This
can be used by debuggers to display the contents of a closure variable.
Based on a sample program (delve) this increases the executable size by 0.06%.
benchstat output:
│ old.txt │ new.txt │
│ sec/op │ sec/op vs base │
Template 153.0m ± 6% 152.5m ± 14% ~ (p=0.684 n=10)
Unicode 100.2m ± 15% 104.9m ± 7% ~ (p=0.247 n=10)
GoTypes 943.6m ± 8% 986.2m ± 10% ~ (p=0.280 n=10)
Compiler 97.79m ± 6% 101.63m ± 12% ~ (p=0.393 n=10)
SSA 6.872 ± 37% 9.413 ± 106% ~ (p=0.190 n=10)
Flate 128.0m ± 36% 125.0m ± 56% ~ (p=0.481 n=10)
GoParser 214.9m ± 26% 201.4m ± 68% ~ (p=0.579 n=10)
Reflect 452.6m ± 22% 412.2m ± 74% ~ (p=0.739 n=10)
Tar 166.2m ± 27% 155.9m ± 73% ~ (p=0.393 n=10)
XML 219.3m ± 24% 211.3m ± 76% ~ (p=0.739 n=10)
LinkCompiler 523.2m ± 13% 513.5m ± 47% ~ (p=0.631 n=10)
ExternalLinkCompiler 1.684 ± 2% 1.659 ± 25% ~ (p=0.218 n=10)
LinkWithoutDebugCompiler 304.9m ± 12% 309.1m ± 7% ~ (p=0.631 n=10)
StdCmd 70.76 ± 14% 68.66 ± 53% ~ (p=1.000 n=10)
geomean 511.5m 515.4m +0.77%
│ old.txt │ new.txt │
│ user-sec/op │ user-sec/op vs base │
Template 269.6m ± 13% 292.3m ± 17% ~ (p=0.393 n=10)
Unicode 110.2m ± 8% 101.7m ± 18% ~ (p=0.247 n=10)
GoTypes 2.181 ± 9% 2.356 ± 12% ~ (p=0.280 n=10)
Compiler 119.1m ± 11% 121.9m ± 15% ~ (p=0.481 n=10)
SSA 17.75 ± 52% 26.94 ± 123% ~ (p=0.190 n=10)
Flate 256.2m ± 43% 226.8m ± 73% ~ (p=0.739 n=10)
GoParser 427.0m ± 24% 422.3m ± 72% ~ (p=0.529 n=10)
Reflect 990.5m ± 23% 905.5m ± 75% ~ (p=0.912 n=10)
Tar 307.9m ± 27% 308.9m ± 64% ~ (p=0.393 n=10)
XML 432.8m ± 24% 427.6m ± 89% ~ (p=0.796 n=10)
LinkCompiler 796.9m ± 14% 800.4m ± 56% ~ (p=0.481 n=10)
ExternalLinkCompiler 1.666 ± 4% 1.671 ± 28% ~ (p=0.971 n=10)
LinkWithoutDebugCompiler 316.7m ± 12% 325.6m ± 8% ~ (p=0.579 n=10)
geomean 579.5m 594.0m +2.51%
│ old.txt │ new.txt │
│ text-bytes │ text-bytes vs base │
HelloSize 842.9Ki ± 0% 842.9Ki ± 0% ~ (p=1.000 n=10) ¹
CmdGoSize 10.95Mi ± 0% 10.95Mi ± 0% ~ (p=1.000 n=10) ¹
geomean 3.003Mi 3.003Mi +0.00%
¹ all samples are equal
│ old.txt │ new.txt │
│ data-bytes │ data-bytes vs base │
HelloSize 15.08Ki ± 0% 15.08Ki ± 0% ~ (p=1.000 n=10) ¹
CmdGoSize 314.7Ki ± 0% 314.7Ki ± 0% ~ (p=1.000 n=10) ¹
geomean 68.88Ki 68.88Ki +0.00%
¹ all samples are equal
│ old.txt │ new.txt │
│ bss-bytes │ bss-bytes vs base │
HelloSize 396.8Ki ± 0% 396.8Ki ± 0% ~ (p=1.000 n=10) ¹
CmdGoSize 428.8Ki ± 0% 428.8Ki ± 0% ~ (p=1.000 n=10) ¹
geomean 412.5Ki 412.5Ki +0.00%
¹ all samples are equal
│ old.txt │ new.txt │
│ exe-bytes │ exe-bytes vs base │
HelloSize 1.310Mi ± 0% 1.310Mi ± 0% +0.02% (p=0.000 n=10)
CmdGoSize 16.37Mi ± 0% 16.38Mi ± 0% +0.01% (p=0.000 n=10)
geomean 4.631Mi 4.632Mi +0.02%
Change-Id: Ib416ee2d916ec61ad4a5c26bab09597595f57e04
Reviewed-on: https://go-review.googlesource.com/c/go/+/563816
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This commit is contained in:
Alessandro Arzilli
Than McIntosh
parent
e8b5bc63be
commit
f048829d70
5 changed files with 172 additions and 45 deletions
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@ -16,6 +16,7 @@ import (
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"cmd/compile/internal/reflectdata"
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"cmd/compile/internal/ssa"
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"cmd/compile/internal/ssagen"
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"cmd/compile/internal/typecheck"
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"cmd/compile/internal/types"
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"cmd/internal/dwarf"
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"cmd/internal/obj"
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@ -100,7 +101,23 @@ func Info(fnsym *obj.LSym, infosym *obj.LSym, curfn obj.Func) (scopes []dwarf.Sc
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}
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}
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decls, dwarfVars := createDwarfVars(fnsym, isODCLFUNC, fn, apdecls)
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var closureVars map[*ir.Name]int64
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if fn.Needctxt() {
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closureVars = make(map[*ir.Name]int64)
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csiter := typecheck.NewClosureStructIter(fn.ClosureVars)
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for {
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n, _, offset := csiter.Next()
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if n == nil {
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break
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}
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closureVars[n] = offset
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if n.Heapaddr != nil {
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closureVars[n.Heapaddr] = offset
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}
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}
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}
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decls, dwarfVars := createDwarfVars(fnsym, isODCLFUNC, fn, apdecls, closureVars)
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// For each type referenced by the functions auto vars but not
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// already referenced by a dwarf var, attach an R_USETYPE relocation to
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@ -137,18 +154,18 @@ func declPos(decl *ir.Name) src.XPos {
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// createDwarfVars process fn, returning a list of DWARF variables and the
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// Nodes they represent.
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func createDwarfVars(fnsym *obj.LSym, complexOK bool, fn *ir.Func, apDecls []*ir.Name) ([]*ir.Name, []*dwarf.Var) {
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func createDwarfVars(fnsym *obj.LSym, complexOK bool, fn *ir.Func, apDecls []*ir.Name, closureVars map[*ir.Name]int64) ([]*ir.Name, []*dwarf.Var) {
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// Collect a raw list of DWARF vars.
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var vars []*dwarf.Var
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var decls []*ir.Name
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var selected ir.NameSet
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if base.Ctxt.Flag_locationlists && base.Ctxt.Flag_optimize && fn.DebugInfo != nil && complexOK {
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decls, vars, selected = createComplexVars(fnsym, fn)
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decls, vars, selected = createComplexVars(fnsym, fn, closureVars)
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} else if fn.ABI == obj.ABIInternal && base.Flag.N != 0 && complexOK {
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decls, vars, selected = createABIVars(fnsym, fn, apDecls)
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decls, vars, selected = createABIVars(fnsym, fn, apDecls, closureVars)
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} else {
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decls, vars, selected = createSimpleVars(fnsym, apDecls)
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decls, vars, selected = createSimpleVars(fnsym, apDecls, closureVars)
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}
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if fn.DebugInfo != nil {
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// Recover zero sized variables eliminated by the stackframe pass
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@ -159,7 +176,7 @@ func createDwarfVars(fnsym *obj.LSym, complexOK bool, fn *ir.Func, apDecls []*ir
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types.CalcSize(n.Type())
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if n.Type().Size() == 0 {
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decls = append(decls, n)
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vars = append(vars, createSimpleVar(fnsym, n))
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vars = append(vars, createSimpleVar(fnsym, n, closureVars))
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vars[len(vars)-1].StackOffset = 0
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fnsym.Func().RecordAutoType(reflectdata.TypeLinksym(n.Type()))
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}
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@ -212,7 +229,7 @@ func createDwarfVars(fnsym *obj.LSym, complexOK bool, fn *ir.Func, apDecls []*ir
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// Args not of SSA-able type are treated here; they
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// are homed on the stack in a single place for the
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// entire call.
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vars = append(vars, createSimpleVar(fnsym, n))
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vars = append(vars, createSimpleVar(fnsym, n, closureVars))
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decls = append(decls, n)
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continue
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}
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@ -251,6 +268,7 @@ func createDwarfVars(fnsym *obj.LSym, complexOK bool, fn *ir.Func, apDecls []*ir
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InlIndex: int32(inlIndex),
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ChildIndex: -1,
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DictIndex: n.DictIndex,
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ClosureOffset: closureOffset(n, closureVars),
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})
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// Record go type of to insure that it gets emitted by the linker.
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fnsym.Func().RecordAutoType(reflectdata.TypeLinksym(n.Type()))
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@ -334,7 +352,7 @@ func preInliningDcls(fnsym *obj.LSym) []*ir.Name {
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// createSimpleVars creates a DWARF entry for every variable declared in the
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// function, claiming that they are permanently on the stack.
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func createSimpleVars(fnsym *obj.LSym, apDecls []*ir.Name) ([]*ir.Name, []*dwarf.Var, ir.NameSet) {
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func createSimpleVars(fnsym *obj.LSym, apDecls []*ir.Name, closureVars map[*ir.Name]int64) ([]*ir.Name, []*dwarf.Var, ir.NameSet) {
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var vars []*dwarf.Var
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var decls []*ir.Name
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var selected ir.NameSet
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@ -344,13 +362,13 @@ func createSimpleVars(fnsym *obj.LSym, apDecls []*ir.Name) ([]*ir.Name, []*dwarf
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}
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decls = append(decls, n)
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vars = append(vars, createSimpleVar(fnsym, n))
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vars = append(vars, createSimpleVar(fnsym, n, closureVars))
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selected.Add(n)
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}
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return decls, vars, selected
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}
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func createSimpleVar(fnsym *obj.LSym, n *ir.Name) *dwarf.Var {
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func createSimpleVar(fnsym *obj.LSym, n *ir.Name, closureVars map[*ir.Name]int64) *dwarf.Var {
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var tag int
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var offs int64
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@ -406,6 +424,7 @@ func createSimpleVar(fnsym *obj.LSym, n *ir.Name) *dwarf.Var {
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InlIndex: int32(inlIndex),
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ChildIndex: -1,
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DictIndex: n.DictIndex,
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ClosureOffset: closureOffset(n, closureVars),
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}
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}
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@ -414,11 +433,11 @@ func createSimpleVar(fnsym *obj.LSym, n *ir.Name) *dwarf.Var {
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// hybrid approach in which register-resident input params are
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// captured with location lists, and all other vars use the "simple"
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// strategy.
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func createABIVars(fnsym *obj.LSym, fn *ir.Func, apDecls []*ir.Name) ([]*ir.Name, []*dwarf.Var, ir.NameSet) {
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func createABIVars(fnsym *obj.LSym, fn *ir.Func, apDecls []*ir.Name, closureVars map[*ir.Name]int64) ([]*ir.Name, []*dwarf.Var, ir.NameSet) {
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// Invoke createComplexVars to generate dwarf vars for input parameters
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// that are register-allocated according to the ABI rules.
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decls, vars, selected := createComplexVars(fnsym, fn)
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decls, vars, selected := createComplexVars(fnsym, fn, closureVars)
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// Now fill in the remainder of the variables: input parameters
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// that are not register-resident, output parameters, and local
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@ -433,7 +452,7 @@ func createABIVars(fnsym *obj.LSym, fn *ir.Func, apDecls []*ir.Name) ([]*ir.Name
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}
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decls = append(decls, n)
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vars = append(vars, createSimpleVar(fnsym, n))
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vars = append(vars, createSimpleVar(fnsym, n, closureVars))
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selected.Add(n)
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}
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@ -442,7 +461,7 @@ func createABIVars(fnsym *obj.LSym, fn *ir.Func, apDecls []*ir.Name) ([]*ir.Name
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// createComplexVars creates recomposed DWARF vars with location lists,
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// suitable for describing optimized code.
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func createComplexVars(fnsym *obj.LSym, fn *ir.Func) ([]*ir.Name, []*dwarf.Var, ir.NameSet) {
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func createComplexVars(fnsym *obj.LSym, fn *ir.Func, closureVars map[*ir.Name]int64) ([]*ir.Name, []*dwarf.Var, ir.NameSet) {
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debugInfo := fn.DebugInfo.(*ssa.FuncDebug)
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// Produce a DWARF variable entry for each user variable.
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@ -457,7 +476,7 @@ func createComplexVars(fnsym *obj.LSym, fn *ir.Func) ([]*ir.Name, []*dwarf.Var,
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ssaVars.Add(debugInfo.Slots[slot].N)
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}
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if dvar := createComplexVar(fnsym, fn, ssa.VarID(varID)); dvar != nil {
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if dvar := createComplexVar(fnsym, fn, ssa.VarID(varID), closureVars); dvar != nil {
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decls = append(decls, n)
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vars = append(vars, dvar)
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}
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@ -467,7 +486,7 @@ func createComplexVars(fnsym *obj.LSym, fn *ir.Func) ([]*ir.Name, []*dwarf.Var,
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}
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// createComplexVar builds a single DWARF variable entry and location list.
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func createComplexVar(fnsym *obj.LSym, fn *ir.Func, varID ssa.VarID) *dwarf.Var {
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func createComplexVar(fnsym *obj.LSym, fn *ir.Func, varID ssa.VarID, closureVars map[*ir.Name]int64) *dwarf.Var {
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debug := fn.DebugInfo.(*ssa.FuncDebug)
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n := debug.Vars[varID]
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@ -505,13 +524,14 @@ func createComplexVar(fnsym *obj.LSym, fn *ir.Func, varID ssa.VarID) *dwarf.Var
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// variables just give it the first one. It's not used otherwise.
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// This won't work well if the first slot hasn't been assigned a stack
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// location, but it's not obvious how to do better.
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StackOffset: ssagen.StackOffset(debug.Slots[debug.VarSlots[varID][0]]),
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DeclFile: declpos.RelFilename(),
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DeclLine: declpos.RelLine(),
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DeclCol: declpos.RelCol(),
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InlIndex: int32(inlIndex),
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ChildIndex: -1,
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DictIndex: n.DictIndex,
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StackOffset: ssagen.StackOffset(debug.Slots[debug.VarSlots[varID][0]]),
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DeclFile: declpos.RelFilename(),
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DeclLine: declpos.RelLine(),
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DeclCol: declpos.RelCol(),
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InlIndex: int32(inlIndex),
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ChildIndex: -1,
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DictIndex: n.DictIndex,
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ClosureOffset: closureOffset(n, closureVars),
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}
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list := debug.LocationLists[varID]
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if len(list) != 0 {
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@ -594,3 +614,7 @@ func RecordPackageName() {
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base.Ctxt.Data = append(base.Ctxt.Data, s)
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s.P = []byte(types.LocalPkg.Name)
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}
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func closureOffset(n *ir.Name, closureVars map[*ir.Name]int64) int64 {
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return closureVars[n]
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}
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