diff options
Diffstat (limited to 'vendor/github.com/google/gops/internal/dwarf/dwarf.go')
| -rw-r--r-- | vendor/github.com/google/gops/internal/dwarf/dwarf.go | 600 |
1 files changed, 0 insertions, 600 deletions
diff --git a/vendor/github.com/google/gops/internal/dwarf/dwarf.go b/vendor/github.com/google/gops/internal/dwarf/dwarf.go deleted file mode 100644 index c72ef5b0..00000000 --- a/vendor/github.com/google/gops/internal/dwarf/dwarf.go +++ /dev/null @@ -1,600 +0,0 @@ -// Copyright 2016 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 dwarf generates DWARF debugging information. -// DWARF generation is split between the compiler and the linker, -// this package contains the shared code. -package dwarf - -import ( - "fmt" -) - -// InfoPrefix is the prefix for all the symbols containing DWARF info entries. -const InfoPrefix = "go.info." - -// Sym represents a symbol. -type Sym interface { -} - -// A Var represents a local variable or a function parameter. -type Var struct { - Name string - Abbrev int // Either DW_ABRV_AUTO or DW_ABRV_PARAM - Offset int32 - Type Sym - Link *Var -} - -// A Context specifies how to add data to a Sym. -type Context interface { - PtrSize() int - AddInt(s Sym, size int, i int64) - AddBytes(s Sym, b []byte) - AddAddress(s Sym, t interface{}, ofs int64) - AddSectionOffset(s Sym, size int, t interface{}, ofs int64) - AddString(s Sym, v string) - SymValue(s Sym) int64 -} - -// AppendUleb128 appends v to b using DWARF's unsigned LEB128 encoding. -func AppendUleb128(b []byte, v uint64) []byte { - for { - c := uint8(v & 0x7f) - v >>= 7 - if v != 0 { - c |= 0x80 - } - b = append(b, c) - if c&0x80 == 0 { - break - } - } - return b -} - -// AppendSleb128 appends v to b using DWARF's signed LEB128 encoding. -func AppendSleb128(b []byte, v int64) []byte { - for { - c := uint8(v & 0x7f) - s := uint8(v & 0x40) - v >>= 7 - if (v != -1 || s == 0) && (v != 0 || s != 0) { - c |= 0x80 - } - b = append(b, c) - if c&0x80 == 0 { - break - } - } - return b -} - -var encbuf [20]byte - -// AppendUleb128 appends v to s using DWARF's unsigned LEB128 encoding. -func Uleb128put(ctxt Context, s Sym, v int64) { - b := AppendUleb128(encbuf[:0], uint64(v)) - ctxt.AddBytes(s, b) -} - -// AppendUleb128 appends v to s using DWARF's signed LEB128 encoding. -func Sleb128put(ctxt Context, s Sym, v int64) { - b := AppendSleb128(encbuf[:0], v) - ctxt.AddBytes(s, b) -} - -/* - * Defining Abbrevs. This is hardcoded, and there will be - * only a handful of them. The DWARF spec places no restriction on - * the ordering of attributes in the Abbrevs and DIEs, and we will - * always write them out in the order of declaration in the abbrev. - */ -type dwAttrForm struct { - attr uint16 - form uint8 -} - -// Go-specific type attributes. -const ( - DW_AT_go_kind = 0x2900 - DW_AT_go_key = 0x2901 - DW_AT_go_elem = 0x2902 - - DW_AT_internal_location = 253 // params and locals; not emitted -) - -// Index into the abbrevs table below. -// Keep in sync with ispubname() and ispubtype() below. -// ispubtype considers >= NULLTYPE public -const ( - DW_ABRV_NULL = iota - DW_ABRV_COMPUNIT - DW_ABRV_FUNCTION - DW_ABRV_VARIABLE - DW_ABRV_AUTO - DW_ABRV_PARAM - DW_ABRV_STRUCTFIELD - DW_ABRV_FUNCTYPEPARAM - DW_ABRV_DOTDOTDOT - DW_ABRV_ARRAYRANGE - DW_ABRV_NULLTYPE - DW_ABRV_BASETYPE - DW_ABRV_ARRAYTYPE - DW_ABRV_CHANTYPE - DW_ABRV_FUNCTYPE - DW_ABRV_IFACETYPE - DW_ABRV_MAPTYPE - DW_ABRV_PTRTYPE - DW_ABRV_BARE_PTRTYPE // only for void*, no DW_AT_type attr to please gdb 6. - DW_ABRV_SLICETYPE - DW_ABRV_STRINGTYPE - DW_ABRV_STRUCTTYPE - DW_ABRV_TYPEDECL - DW_NABRV -) - -type dwAbbrev struct { - tag uint8 - children uint8 - attr []dwAttrForm -} - -var abbrevs = [DW_NABRV]dwAbbrev{ - /* The mandatory DW_ABRV_NULL entry. */ - {0, 0, []dwAttrForm{}}, - - /* COMPUNIT */ - { - DW_TAG_compile_unit, - DW_CHILDREN_yes, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_language, DW_FORM_data1}, - {DW_AT_low_pc, DW_FORM_addr}, - {DW_AT_high_pc, DW_FORM_addr}, - {DW_AT_stmt_list, DW_FORM_data4}, - {DW_AT_comp_dir, DW_FORM_string}, - }, - }, - - /* FUNCTION */ - { - DW_TAG_subprogram, - DW_CHILDREN_yes, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_low_pc, DW_FORM_addr}, - {DW_AT_high_pc, DW_FORM_addr}, - {DW_AT_external, DW_FORM_flag}, - }, - }, - - /* VARIABLE */ - { - DW_TAG_variable, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_location, DW_FORM_block1}, - {DW_AT_type, DW_FORM_ref_addr}, - {DW_AT_external, DW_FORM_flag}, - }, - }, - - /* AUTO */ - { - DW_TAG_variable, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_location, DW_FORM_block1}, - {DW_AT_type, DW_FORM_ref_addr}, - }, - }, - - /* PARAM */ - { - DW_TAG_formal_parameter, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_location, DW_FORM_block1}, - {DW_AT_type, DW_FORM_ref_addr}, - }, - }, - - /* STRUCTFIELD */ - { - DW_TAG_member, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_data_member_location, DW_FORM_block1}, - {DW_AT_type, DW_FORM_ref_addr}, - }, - }, - - /* FUNCTYPEPARAM */ - { - DW_TAG_formal_parameter, - DW_CHILDREN_no, - - // No name! - []dwAttrForm{ - {DW_AT_type, DW_FORM_ref_addr}, - }, - }, - - /* DOTDOTDOT */ - { - DW_TAG_unspecified_parameters, - DW_CHILDREN_no, - []dwAttrForm{}, - }, - - /* ARRAYRANGE */ - { - DW_TAG_subrange_type, - DW_CHILDREN_no, - - // No name! - []dwAttrForm{ - {DW_AT_type, DW_FORM_ref_addr}, - {DW_AT_count, DW_FORM_udata}, - }, - }, - - // Below here are the types considered public by ispubtype - /* NULLTYPE */ - { - DW_TAG_unspecified_type, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - }, - }, - - /* BASETYPE */ - { - DW_TAG_base_type, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_encoding, DW_FORM_data1}, - {DW_AT_byte_size, DW_FORM_data1}, - {DW_AT_go_kind, DW_FORM_data1}, - }, - }, - - /* ARRAYTYPE */ - // child is subrange with upper bound - { - DW_TAG_array_type, - DW_CHILDREN_yes, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_type, DW_FORM_ref_addr}, - {DW_AT_byte_size, DW_FORM_udata}, - {DW_AT_go_kind, DW_FORM_data1}, - }, - }, - - /* CHANTYPE */ - { - DW_TAG_typedef, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_type, DW_FORM_ref_addr}, - {DW_AT_go_kind, DW_FORM_data1}, - {DW_AT_go_elem, DW_FORM_ref_addr}, - }, - }, - - /* FUNCTYPE */ - { - DW_TAG_subroutine_type, - DW_CHILDREN_yes, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - // {DW_AT_type, DW_FORM_ref_addr}, - {DW_AT_go_kind, DW_FORM_data1}, - }, - }, - - /* IFACETYPE */ - { - DW_TAG_typedef, - DW_CHILDREN_yes, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_type, DW_FORM_ref_addr}, - {DW_AT_go_kind, DW_FORM_data1}, - }, - }, - - /* MAPTYPE */ - { - DW_TAG_typedef, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_type, DW_FORM_ref_addr}, - {DW_AT_go_kind, DW_FORM_data1}, - {DW_AT_go_key, DW_FORM_ref_addr}, - {DW_AT_go_elem, DW_FORM_ref_addr}, - }, - }, - - /* PTRTYPE */ - { - DW_TAG_pointer_type, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_type, DW_FORM_ref_addr}, - {DW_AT_go_kind, DW_FORM_data1}, - }, - }, - - /* BARE_PTRTYPE */ - { - DW_TAG_pointer_type, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - }, - }, - - /* SLICETYPE */ - { - DW_TAG_structure_type, - DW_CHILDREN_yes, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_byte_size, DW_FORM_udata}, - {DW_AT_go_kind, DW_FORM_data1}, - {DW_AT_go_elem, DW_FORM_ref_addr}, - }, - }, - - /* STRINGTYPE */ - { - DW_TAG_structure_type, - DW_CHILDREN_yes, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_byte_size, DW_FORM_udata}, - {DW_AT_go_kind, DW_FORM_data1}, - }, - }, - - /* STRUCTTYPE */ - { - DW_TAG_structure_type, - DW_CHILDREN_yes, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_byte_size, DW_FORM_udata}, - {DW_AT_go_kind, DW_FORM_data1}, - }, - }, - - /* TYPEDECL */ - { - DW_TAG_typedef, - DW_CHILDREN_no, - []dwAttrForm{ - {DW_AT_name, DW_FORM_string}, - {DW_AT_type, DW_FORM_ref_addr}, - }, - }, -} - -// GetAbbrev returns the contents of the .debug_abbrev section. -func GetAbbrev() []byte { - var buf []byte - for i := 1; i < DW_NABRV; i++ { - // See section 7.5.3 - buf = AppendUleb128(buf, uint64(i)) - - buf = AppendUleb128(buf, uint64(abbrevs[i].tag)) - buf = append(buf, byte(abbrevs[i].children)) - for _, f := range abbrevs[i].attr { - buf = AppendUleb128(buf, uint64(f.attr)) - buf = AppendUleb128(buf, uint64(f.form)) - } - buf = append(buf, 0, 0) - } - return append(buf, 0) -} - -/* - * Debugging Information Entries and their attributes. - */ - -// DWAttr represents an attribute of a DWDie. -// -// For DW_CLS_string and _block, value should contain the length, and -// data the data, for _reference, value is 0 and data is a DWDie* to -// the referenced instance, for all others, value is the whole thing -// and data is null. -type DWAttr struct { - Link *DWAttr - Atr uint16 // DW_AT_ - Cls uint8 // DW_CLS_ - Value int64 - Data interface{} -} - -// DWDie represents a DWARF debug info entry. -type DWDie struct { - Abbrev int - Link *DWDie - Child *DWDie - Attr *DWAttr - Sym Sym -} - -func putattr(ctxt Context, s Sym, abbrev int, form int, cls int, value int64, data interface{}) error { - switch form { - case DW_FORM_addr: // address - ctxt.AddAddress(s, data, value) - - case DW_FORM_block1: // block - if cls == DW_CLS_ADDRESS { - ctxt.AddInt(s, 1, int64(1+ctxt.PtrSize())) - ctxt.AddInt(s, 1, DW_OP_addr) - ctxt.AddAddress(s, data, 0) - break - } - - value &= 0xff - ctxt.AddInt(s, 1, value) - p := data.([]byte)[:value] - ctxt.AddBytes(s, p) - - case DW_FORM_block2: // block - value &= 0xffff - - ctxt.AddInt(s, 2, value) - p := data.([]byte)[:value] - ctxt.AddBytes(s, p) - - case DW_FORM_block4: // block - value &= 0xffffffff - - ctxt.AddInt(s, 4, value) - p := data.([]byte)[:value] - ctxt.AddBytes(s, p) - - case DW_FORM_block: // block - Uleb128put(ctxt, s, value) - - p := data.([]byte)[:value] - ctxt.AddBytes(s, p) - - case DW_FORM_data1: // constant - ctxt.AddInt(s, 1, value) - - case DW_FORM_data2: // constant - ctxt.AddInt(s, 2, value) - - case DW_FORM_data4: // constant, {line,loclist,mac,rangelist}ptr - if cls == DW_CLS_PTR { // DW_AT_stmt_list - ctxt.AddSectionOffset(s, 4, data, 0) - break - } - ctxt.AddInt(s, 4, value) - - case DW_FORM_data8: // constant, {line,loclist,mac,rangelist}ptr - ctxt.AddInt(s, 8, value) - - case DW_FORM_sdata: // constant - Sleb128put(ctxt, s, value) - - case DW_FORM_udata: // constant - Uleb128put(ctxt, s, value) - - case DW_FORM_string: // string - str := data.(string) - ctxt.AddString(s, str) - // TODO(ribrdb): verify padded strings are never used and remove this - for i := int64(len(str)); i < value; i++ { - ctxt.AddInt(s, 1, 0) - } - - case DW_FORM_flag: // flag - if value != 0 { - ctxt.AddInt(s, 1, 1) - } else { - ctxt.AddInt(s, 1, 0) - } - - // In DWARF 2 (which is what we claim to generate), - // the ref_addr is the same size as a normal address. - // In DWARF 3 it is always 32 bits, unless emitting a large - // (> 4 GB of debug info aka "64-bit") unit, which we don't implement. - case DW_FORM_ref_addr: // reference to a DIE in the .info section - if data == nil { - return fmt.Errorf("dwarf: null reference in %d", abbrev) - } else { - ctxt.AddSectionOffset(s, ctxt.PtrSize(), data, 0) - } - - case DW_FORM_ref1, // reference within the compilation unit - DW_FORM_ref2, // reference - DW_FORM_ref4, // reference - DW_FORM_ref8, // reference - DW_FORM_ref_udata, // reference - - DW_FORM_strp, // string - DW_FORM_indirect: // (see Section 7.5.3) - fallthrough - default: - return fmt.Errorf("dwarf: unsupported attribute form %d / class %d", form, cls) - } - return nil -} - -// PutAttrs writes the attributes for a DIE to symbol 's'. -// -// Note that we can (and do) add arbitrary attributes to a DIE, but -// only the ones actually listed in the Abbrev will be written out. -func PutAttrs(ctxt Context, s Sym, abbrev int, attr *DWAttr) { -Outer: - for _, f := range abbrevs[abbrev].attr { - for ap := attr; ap != nil; ap = ap.Link { - if ap.Atr == f.attr { - putattr(ctxt, s, abbrev, int(f.form), int(ap.Cls), ap.Value, ap.Data) - continue Outer - } - } - - putattr(ctxt, s, abbrev, int(f.form), 0, 0, nil) - } -} - -// HasChildren returns true if 'die' uses an abbrev that supports children. -func HasChildren(die *DWDie) bool { - return abbrevs[die.Abbrev].children != 0 -} - -// PutFunc writes a DIE for a function to s. -// It also writes child DIEs for each variable in vars. -func PutFunc(ctxt Context, s Sym, name string, external bool, startPC Sym, size int64, vars *Var) { - Uleb128put(ctxt, s, DW_ABRV_FUNCTION) - putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_string, DW_CLS_STRING, int64(len(name)), name) - putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_addr, DW_CLS_ADDRESS, 0, startPC) - putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_addr, DW_CLS_ADDRESS, size+ctxt.SymValue(startPC), startPC) - var ev int64 - if external { - ev = 1 - } - putattr(ctxt, s, DW_ABRV_FUNCTION, DW_FORM_flag, DW_CLS_FLAG, ev, 0) - names := make(map[string]bool) - for v := vars; v != nil; v = v.Link { - var n string - if names[v.Name] { - n = fmt.Sprintf("%s#%d", v.Name, len(names)) - } else { - n = v.Name - } - names[n] = true - - Uleb128put(ctxt, s, int64(v.Abbrev)) - putattr(ctxt, s, v.Abbrev, DW_FORM_string, DW_CLS_STRING, int64(len(n)), n) - loc := append(encbuf[:0], DW_OP_call_frame_cfa) - if v.Offset != 0 { - loc = append(loc, DW_OP_consts) - loc = AppendSleb128(loc, int64(v.Offset)) - loc = append(loc, DW_OP_plus) - } - putattr(ctxt, s, v.Abbrev, DW_FORM_block1, DW_CLS_BLOCK, int64(len(loc)), loc) - putattr(ctxt, s, v.Abbrev, DW_FORM_ref_addr, DW_CLS_REFERENCE, 0, v.Type) - - } - Uleb128put(ctxt, s, 0) -} |