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cmd/compile: for non-SSA-typed params, emit simple vars.

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This case was missed entirely and caused such params to be
unprintable.  This change gives them stack addresses
for the entire function (which is correct).

Change-Id: Ia4f706450219e48bce65b6395d3d9792df142fb5
Reviewed-on: https://go-review.googlesource.com/c/150657
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
This commit is contained in:
David Chase 2018-11-20 16:33:33 -05:00
parent 8c5c2b71f4
commit 72496e35ce
1 changed files with 66 additions and 46 deletions
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112
src/cmd/compile/internal/gc/pgen.go
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@ -441,57 +441,62 @@ func createSimpleVars(automDecls []*Node) ([]*Node, []*dwarf.Var, map[*Node]bool
if n.IsAutoTmp() {
continue
}
var abbrev int
offs := n.Xoffset
switch n.Class() {
case PAUTO:
abbrev = dwarf.DW_ABRV_AUTO
if Ctxt.FixedFrameSize() == 0 {
offs -= int64(Widthptr)
}
if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) || objabi.GOARCH == "arm64" {
// There is a word space for FP on ARM64 even if the frame pointer is disabled
offs -= int64(Widthptr)
}
case PPARAM, PPARAMOUT:
abbrev = dwarf.DW_ABRV_PARAM
offs += Ctxt.FixedFrameSize()
default:
Fatalf("createSimpleVars unexpected type %v for node %v", n.Class(), n)
}
selected[n] = true
typename := dwarf.InfoPrefix + typesymname(n.Type)
decls = append(decls, n)
inlIndex := 0
if genDwarfInline > 1 {
if n.InlFormal() || n.InlLocal() {
inlIndex = posInlIndex(n.Pos) + 1
if n.InlFormal() {
abbrev = dwarf.DW_ABRV_PARAM
}
}
}
declpos := Ctxt.InnermostPos(n.Pos)
vars = append(vars, &dwarf.Var{
Name: n.Sym.Name,
IsReturnValue: n.Class() == PPARAMOUT,
IsInlFormal: n.InlFormal(),
Abbrev: abbrev,
StackOffset: int32(offs),
Type: Ctxt.Lookup(typename),
DeclFile: declpos.RelFilename(),
DeclLine: declpos.RelLine(),
DeclCol: declpos.Col(),
InlIndex: int32(inlIndex),
ChildIndex: -1,
})
vars = append(vars, createSimpleVar(n))
selected[n] = true
}
return decls, vars, selected
}
func createSimpleVar(n *Node) *dwarf.Var {
var abbrev int
offs := n.Xoffset
switch n.Class() {
case PAUTO:
abbrev = dwarf.DW_ABRV_AUTO
if Ctxt.FixedFrameSize() == 0 {
offs -= int64(Widthptr)
}
if objabi.Framepointer_enabled(objabi.GOOS, objabi.GOARCH) || objabi.GOARCH == "arm64" {
// There is a word space for FP on ARM64 even if the frame pointer is disabled
offs -= int64(Widthptr)
}
case PPARAM, PPARAMOUT:
abbrev = dwarf.DW_ABRV_PARAM
offs += Ctxt.FixedFrameSize()
default:
Fatalf("createSimpleVar unexpected class %v for node %v", n.Class(), n)
}
typename := dwarf.InfoPrefix + typesymname(n.Type)
inlIndex := 0
if genDwarfInline > 1 {
if n.InlFormal() || n.InlLocal() {
inlIndex = posInlIndex(n.Pos) + 1
if n.InlFormal() {
abbrev = dwarf.DW_ABRV_PARAM
}
}
}
declpos := Ctxt.InnermostPos(n.Pos)
return &dwarf.Var{
Name: n.Sym.Name,
IsReturnValue: n.Class() == PPARAMOUT,
IsInlFormal: n.InlFormal(),
Abbrev: abbrev,
StackOffset: int32(offs),
Type: Ctxt.Lookup(typename),
DeclFile: declpos.RelFilename(),
DeclLine: declpos.RelLine(),
DeclCol: declpos.Col(),
InlIndex: int32(inlIndex),
ChildIndex: -1,
}
}
// createComplexVars creates recomposed DWARF vars with location lists,
// suitable for describing optimized code.
func createComplexVars(fn *Func) ([]*Node, []*dwarf.Var, map[*Node]bool) {
@ -541,12 +546,15 @@ func createDwarfVars(fnsym *obj.LSym, fn *Func, automDecls []*Node) ([]*Node, []
// If optimization is enabled, the list above will typically be
// missing some of the original pre-optimization variables in the
// function (they may have been promoted to registers, folded into
// constants, dead-coded away, etc). Here we add back in entries
// constants, dead-coded away, etc). Input arguments not eligible
// for SSA optimization are also missing. Here we add back in entries
// for selected missing vars. Note that the recipe below creates a
// conservative location. The idea here is that we want to
// communicate to the user that "yes, there is a variable named X
// in this function, but no, I don't have enough information to
// reliably report its contents."
// For non-SSA-able arguments, however, the correct information
// is known -- they have a single home on the stack.
for _, n := range dcl {
if _, found := selected[n]; found {
continue
@ -555,6 +563,18 @@ func createDwarfVars(fnsym *obj.LSym, fn *Func, automDecls []*Node) ([]*Node, []
if c == '.' || n.Type.IsUntyped() {
continue
}
if n.Class() == PPARAM && !canSSAType(n.Type) {
// SSA-able args get location lists, and may move in and
// out of registers, so those are handled elsewhere.
// Autos and named output params seem to get handled
// with VARDEF, which creates location lists.
// Args not of SSA-able type are treated here; they
// are homed on the stack in a single place for the
// entire call.
vars = append(vars, createSimpleVar(n))
decls = append(decls, n)
continue
}
typename := dwarf.InfoPrefix + typesymname(n.Type)
decls = append(decls, n)
abbrev := dwarf.DW_ABRV_AUTO_LOCLIST