AuxPcinline
AuxPcdata
AuxWasmImport
+ AuxSehUnwindInfo
)
func (a *Aux) Type() uint8 { return a[0] }
FuncInfoSym *LSym
WasmImportSym *LSym
WasmImport *WasmImport
+
+ sehUnwindInfoSym *LSym
}
// JumpTable represents a table used for implementing multi-way
Preprocess func(*Link, *LSym, ProgAlloc)
Assemble func(*Link, *LSym, ProgAlloc)
Progedit func(*Link, *Prog, ProgAlloc)
+ SEH func(*Link, *LSym) *LSym
UnaryDst map[As]bool // Instruction takes one operand, a destination.
DWARFRegisters map[int16]int16
}
if fn.Pcln.Pcinline != nil && fn.Pcln.Pcinline.Size != 0 {
w.aux1(goobj.AuxPcinline, fn.Pcln.Pcinline)
}
+ if fn.sehUnwindInfoSym != nil && fn.sehUnwindInfoSym.Size != 0 {
+ w.aux1(goobj.AuxSehUnwindInfo, fn.sehUnwindInfoSym)
+ }
for _, pcSym := range fn.Pcln.Pcdata {
w.aux1(goobj.AuxPcdata, pcSym)
}
if fn.Pcln.Pcinline != nil && fn.Pcln.Pcinline.Size != 0 {
n++
}
+ if fn.sehUnwindInfoSym != nil && fn.sehUnwindInfoSym.Size != 0 {
+ n++
+ }
n += len(fn.Pcln.Pcdata)
if fn.WasmImport != nil {
if fn.WasmImportSym == nil || fn.WasmImportSym.Size == 0 {
fn.FuncInfoSym = isym
b.Reset()
- auxsyms := []*LSym{fn.dwarfRangesSym, fn.dwarfLocSym, fn.dwarfDebugLinesSym, fn.dwarfInfoSym, fn.WasmImportSym}
+ auxsyms := []*LSym{fn.dwarfRangesSym, fn.dwarfLocSym, fn.dwarfDebugLinesSym, fn.dwarfInfoSym, fn.WasmImportSym, fn.sehUnwindInfoSym}
for _, s := range auxsyms {
if s == nil || s.Size == 0 {
continue
if myimportpath != "" {
ctxt.populateDWARF(plist.Curfn, s, myimportpath)
}
+ if ctxt.Headtype == objabi.Hwindows && ctxt.Arch.SEH != nil {
+ s.Func().sehUnwindInfoSym = ctxt.Arch.SEH(ctxt, s)
+ }
}
}
}
}
- auxsyms := []*LSym{fninfo.dwarfRangesSym, fninfo.dwarfLocSym, fninfo.dwarfDebugLinesSym, fninfo.dwarfInfoSym, fninfo.WasmImportSym}
+ auxsyms := []*LSym{fninfo.dwarfRangesSym, fninfo.dwarfLocSym, fninfo.dwarfDebugLinesSym, fninfo.dwarfInfoSym, fninfo.WasmImportSym, fninfo.sehUnwindInfoSym}
for _, s := range auxsyms {
if s == nil || s.Size == 0 {
continue
p.To.Offset += int64(bpsize)
} else {
bpsize = 0
+ p.From.Sym.Set(obj.AttrNoFrame, true)
}
textarg := int64(p.To.Val.(int32))
Preprocess: preprocess,
Assemble: span6,
Progedit: progedit,
+ SEH: populateSeh,
UnaryDst: unaryDst,
DWARFRegisters: AMD64DWARFRegisters,
}
--- /dev/null
+// Copyright 2023 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 x86
+
+import (
+ "cmd/internal/obj"
+ "cmd/internal/objabi"
+ "cmd/internal/src"
+ "encoding/base64"
+ "fmt"
+ "math"
+)
+
+type sehbuf struct {
+ ctxt *obj.Link
+ data []byte
+ off int
+}
+
+func newsehbuf(ctxt *obj.Link, nodes uint8) sehbuf {
+ // - 8 bytes for the header
+ // - 2 bytes for each node
+ // - 2 bytes in case nodes is not even
+ size := 8 + nodes*2
+ if nodes%2 != 0 {
+ size += 2
+ }
+ return sehbuf{ctxt, make([]byte, size), 0}
+}
+
+func (b *sehbuf) write8(v uint8) {
+ b.data[b.off] = v
+ b.off++
+}
+
+func (b *sehbuf) write32(v uint32) {
+ b.ctxt.Arch.ByteOrder.PutUint32(b.data[b.off:], v)
+ b.off += 4
+}
+
+func (b *sehbuf) writecode(op, value uint8) {
+ b.write8(value<<4 | op)
+}
+
+// populateSeh generates the SEH unwind information for s.
+func populateSeh(ctxt *obj.Link, s *obj.LSym) (sehsym *obj.LSym) {
+ if s.NoFrame() {
+ return
+ }
+
+ // This implementation expects the following function prologue layout:
+ // - Stack split code (optional)
+ // - PUSHQ BP
+ // - MOVQ SP, BP
+ //
+ // If the prologue layout change, the unwind information should be updated
+ // accordingly.
+
+ // Search for the PUSHQ BP instruction inside the prologue.
+ var pushbp *obj.Prog
+ for p := s.Func().Text; p != nil; p = p.Link {
+ if p.As == APUSHQ && p.From.Type == obj.TYPE_REG && p.From.Reg == REG_BP {
+ pushbp = p
+ break
+ }
+ if p.Pos.Xlogue() == src.PosPrologueEnd {
+ break
+ }
+ }
+ if pushbp == nil {
+ ctxt.Diag("missing frame pointer instruction: PUSHQ BP")
+ return
+ }
+
+ // It must be followed by a MOVQ SP, BP.
+ movbp := pushbp.Link
+ if movbp == nil {
+ ctxt.Diag("missing frame pointer instruction: MOVQ SP, BP")
+ return
+ }
+ if !(movbp.As == AMOVQ && movbp.From.Type == obj.TYPE_REG && movbp.From.Reg == REG_SP &&
+ movbp.To.Type == obj.TYPE_REG && movbp.To.Reg == REG_BP && movbp.From.Offset == 0) {
+ ctxt.Diag("unexpected frame pointer instruction\n%v", movbp)
+ return
+ }
+ if movbp.Link.Pc > math.MaxUint8 {
+ // SEH unwind information don't support prologues that are more than 255 bytes long.
+ // These are very rare, but still possible, e.g., when compiling functions with many
+ // parameters with -gcflags=-d=maymorestack=runtime.mayMoreStackPreempt.
+ // Return without reporting an error.
+ return
+ }
+
+ // Reference:
+ // https://learn.microsoft.com/en-us/cpp/build/exception-handling-x64#struct-unwind_info
+
+ const (
+ UWOP_PUSH_NONVOL = 0
+ UWOP_SET_FPREG = 3
+ SEH_REG_BP = 5
+ )
+
+ // Fow now we only support operations which are encoded
+ // using a single 2-byte node, so the number of nodes
+ // is the number of operations.
+ nodes := uint8(2)
+ buf := newsehbuf(ctxt, nodes)
+ buf.write8(1) // Flags + version
+ buf.write8(uint8(movbp.Link.Pc)) // Size of prolog
+ buf.write8(nodes) // Count of nodes
+ buf.write8(SEH_REG_BP) // FP register
+
+ // Notes are written in reverse order of appearance.
+ buf.write8(uint8(movbp.Link.Pc))
+ buf.writecode(UWOP_SET_FPREG, 0)
+
+ buf.write8(uint8(pushbp.Link.Pc))
+ buf.writecode(UWOP_PUSH_NONVOL, SEH_REG_BP)
+
+ // The following 4 bytes reference the RVA of the exception handler,
+ // in case the function has one. We don't use it for now.
+ buf.write32(0)
+
+ // The list of unwind infos in a PE binary have very low cardinality
+ // as each info only contains frame pointer operations,
+ // which are very similar across functions.
+ // Dedup them when possible.
+ hash := base64.StdEncoding.EncodeToString(buf.data)
+ symname := fmt.Sprintf("%d.%s", len(buf.data), hash)
+ return ctxt.LookupInit("go:sehuw."+symname, func(s *obj.LSym) {
+ s.WriteBytes(ctxt, 0, buf.data)
+ s.Type = objabi.SSEHUNWINDINFO
+ s.Set(obj.AttrDuplicateOK, true)
+ s.Set(obj.AttrLocal, true)
+ // Note: AttrContentAddressable cannot be set here,
+ // because the content-addressable-handling code
+ // does not know about aux symbols.
+ })
+}
SCOVERAGE_COUNTER
SCOVERAGE_AUXVAR
+ SSEHUNWINDINFO
// Update cmd/link/internal/sym/AbiSymKindToSymKind for new SymKind values.
)
_ = x[SLIBFUZZER_8BIT_COUNTER-17]
_ = x[SCOVERAGE_COUNTER-18]
_ = x[SCOVERAGE_AUXVAR-19]
+ _ = x[SSEHUNWINDINFO-20]
}
-const _SymKind_name = "SxxxSTEXTSRODATASNOPTRDATASDATASBSSSNOPTRBSSSTLSBSSSDWARFCUINFOSDWARFCONSTSDWARFFCNSDWARFABSFCNSDWARFTYPESDWARFVARSDWARFRANGESDWARFLOCSDWARFLINESSLIBFUZZER_8BIT_COUNTERSCOVERAGE_COUNTERSCOVERAGE_AUXVAR"
+const _SymKind_name = "SxxxSTEXTSRODATASNOPTRDATASDATASBSSSNOPTRBSSSTLSBSSSDWARFCUINFOSDWARFCONSTSDWARFFCNSDWARFABSFCNSDWARFTYPESDWARFVARSDWARFRANGESDWARFLOCSDWARFLINESSLIBFUZZER_8BIT_COUNTERSCOVERAGE_COUNTERSCOVERAGE_AUXVARSSEHUNWINDINFO"
-var _SymKind_index = [...]uint8{0, 4, 9, 16, 26, 31, 35, 44, 51, 63, 74, 83, 95, 105, 114, 125, 134, 145, 168, 185, 201}
+var _SymKind_index = [...]uint8{0, 4, 9, 16, 26, 31, 35, 44, 51, 63, 74, 83, 95, 105, 114, 125, 134, 145, 168, 185, 201, 215}
func (i SymKind) String() string {
if i >= SymKind(len(_SymKind_index)-1) {
SDWARFRANGE
SDWARFLOC
SDWARFLINES
+
+ // SEH symbol types
+ SSEHUNWINDINFO
)
// AbiSymKindToSymKind maps values read from object files (which are
objabi.SLIBFUZZER_8BIT_COUNTER: SLIBFUZZER_8BIT_COUNTER,
objabi.SCOVERAGE_COUNTER: SCOVERAGE_COUNTER,
objabi.SCOVERAGE_AUXVAR: SCOVERAGE_AUXVAR,
+ objabi.SSEHUNWINDINFO: SSEHUNWINDINFO,
}
// ReadOnly are the symbol kinds that form read-only sections. In some
-// Code generated by "stringer -type=SymKind symkind.go"; DO NOT EDIT.
+// Code generated by "stringer -type=SymKind"; DO NOT EDIT.
package sym
_ = x[SDWARFRANGE-56]
_ = x[SDWARFLOC-57]
_ = x[SDWARFLINES-58]
+ _ = x[SSEHUNWINDINFO-59]
}
-const _SymKind_name = "SxxxSTEXTSELFRXSECTSMACHOPLTSTYPESSTRINGSGOSTRINGSGOFUNCSGCBITSSRODATASFUNCTABSELFROSECTSTYPERELROSSTRINGRELROSGOSTRINGRELROSGOFUNCRELROSGCBITSRELROSRODATARELROSFUNCTABRELROSTYPELINKSITABLINKSSYMTABSPCLNTABSFirstWritableSBUILDINFOSELFSECTSMACHOSMACHOGOTSWINDOWSSELFGOTSNOPTRDATASINITARRSDATASXCOFFTOCSBSSSNOPTRBSSSLIBFUZZER_8BIT_COUNTERSCOVERAGE_COUNTERSCOVERAGE_AUXVARSTLSBSSSXREFSMACHOSYMSTRSMACHOSYMTABSMACHOINDIRECTPLTSMACHOINDIRECTGOTSFILEPATHSDYNIMPORTSHOSTOBJSUNDEFEXTSDWARFSECTSDWARFCUINFOSDWARFCONSTSDWARFFCNSDWARFABSFCNSDWARFTYPESDWARFVARSDWARFRANGESDWARFLOCSDWARFLINES"
+const _SymKind_name = "SxxxSTEXTSELFRXSECTSMACHOPLTSTYPESSTRINGSGOSTRINGSGOFUNCSGCBITSSRODATASFUNCTABSELFROSECTSTYPERELROSSTRINGRELROSGOSTRINGRELROSGOFUNCRELROSGCBITSRELROSRODATARELROSFUNCTABRELROSTYPELINKSITABLINKSSYMTABSPCLNTABSFirstWritableSBUILDINFOSELFSECTSMACHOSMACHOGOTSWINDOWSSELFGOTSNOPTRDATASINITARRSDATASXCOFFTOCSBSSSNOPTRBSSSLIBFUZZER_8BIT_COUNTERSCOVERAGE_COUNTERSCOVERAGE_AUXVARSTLSBSSSXREFSMACHOSYMSTRSMACHOSYMTABSMACHOINDIRECTPLTSMACHOINDIRECTGOTSFILEPATHSDYNIMPORTSHOSTOBJSUNDEFEXTSDWARFSECTSDWARFCUINFOSDWARFCONSTSDWARFFCNSDWARFABSFCNSDWARFTYPESDWARFVARSDWARFRANGESDWARFLOCSDWARFLINESSSEHUNWINDINFO"
-var _SymKind_index = [...]uint16{0, 4, 9, 19, 28, 33, 40, 49, 56, 63, 70, 78, 88, 98, 110, 124, 136, 148, 160, 173, 182, 191, 198, 206, 220, 230, 238, 244, 253, 261, 268, 278, 286, 291, 300, 304, 313, 336, 353, 369, 376, 381, 393, 405, 422, 439, 448, 458, 466, 475, 485, 497, 508, 517, 529, 539, 548, 559, 568, 579}
+var _SymKind_index = [...]uint16{0, 4, 9, 19, 28, 33, 40, 49, 56, 63, 70, 78, 88, 98, 110, 124, 136, 148, 160, 173, 182, 191, 198, 206, 220, 230, 238, 244, 253, 261, 268, 278, 286, 291, 300, 304, 313, 336, 353, 369, 376, 381, 393, 405, 422, 439, 448, 458, 466, 475, 485, 497, 508, 517, 529, 539, 548, 559, 568, 579, 593}
func (i SymKind) String() string {
if i >= SymKind(len(_SymKind_index)-1) {