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dwarfdbginf.d
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dwarfdbginf.d
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/**
* Emit Dwarf symbolic debug info
*
* Compiler implementation of the
* $(LINK2 http://www.dlang.org, D programming language).
*
* Copyright: Copyright (C) 1999-2021 by The D Language Foundation, All Rights Reserved
* Authors: $(LINK2 http://www.digitalmars.com, Walter Bright)
* License: $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost License 1.0)
* Source: $(LINK2 https://github.com/dlang/dmd/blob/master/src/dmd/backend/dwarfdbginf.d, backend/dwarfdbginf.d)
* Coverage: https://codecov.io/gh/dlang/dmd/src/master/src/dmd/backend/dwarfdbginf.d
*/
/*
Some generic information for debug info on macOS:
The linker on macOS will remove any debug info, i.e. every section with the
`S_ATTR_DEBUG` flag, this includes everything in the `__DWARF` section. By using
the `S_REGULAR` flag the linker will not remove this section. This allows to get
the filenames and line numbers for backtraces from the executable.
Normally the linker removes all the debug info but adds a reference to the
object files. The debugger can then read the object files to get filename and
line number information. It's also possible to use an additional tool that
generates a separate `.dSYM` file. This file can then later be deployed with the
application if debug info is needed when the application is deployed.
*/
module dmd.backend.dwarfdbginf;
version (SCPP)
version = COMPILE;
version (MARS)
version = COMPILE;
version (COMPILE):
import core.stdc.stdio;
import core.stdc.stdlib;
import core.stdc.string;
import core.stdc.errno;
import dmd.backend.cc;
import dmd.backend.cdef;
version(Windows)
{
nothrow
extern (C) char* getcwd(char* buffer, size_t maxlen);
nothrow
extern (C) int* _errno(); // not the multi-threaded version
}
else
{
import core.sys.posix.unistd : getcwd;
}
static if (1)
{
import dmd.backend.aarray;
import dmd.backend.barray;
import dmd.backend.code;
import dmd.backend.code_x86;
import dmd.backend.dwarf;
import dmd.backend.dwarf2;
import dmd.backend.mem;
import dmd.backend.dlist;
import dmd.backend.el;
import dmd.backend.filespec;
import dmd.backend.global;
import dmd.backend.obj;
import dmd.backend.oper;
import dmd.backend.symtab;
import dmd.backend.ty;
import dmd.backend.type;
import dmd.backend.melf;
import dmd.backend.mach;
import dmd.common.outbuffer;
extern (C++):
nothrow:
int REGSIZE();
__gshared
{
//static if (MACHOBJ)
int except_table_seg = UNKNOWN; // __gcc_except_tab segment
int except_table_num = 0; // sequence number for GCC_except_table%d symbols
int eh_frame_seg = UNKNOWN; // __eh_frame segment
Symbol *eh_frame_sym = null; // past end of __eh_frame
uint CIE_offset_unwind; // CIE offset for unwind data
uint CIE_offset_no_unwind; // CIE offset for no unwind data
IDXSYM elf_addsym(IDXSTR nam, targ_size_t val, uint sz,
uint typ, uint bind, IDXSEC sec,
ubyte visibility = STV_DEFAULT);
void addSegmentToComdat(segidx_t seg, segidx_t comdatseg);
int getsegment2(ref int seg, const(char)* sectname, const(char)* segname,
int align_, int flags);
Symbol* getRtlsymPersonality();
private Barray!(Symbol*) resetSyms; // Keep pointers to reset symbols
}
/***********************************
* Determine if generating a eh_frame with full
* unwinding information.
* This decision is done on a per-function basis.
* Returns:
* true if unwinding needs to be done
*/
bool doUnwindEhFrame()
{
if (funcsym_p.Sfunc.Fflags3 & Feh_none)
{
return (config.exe & (EX_FREEBSD | EX_FREEBSD64 | EX_OPENBSD | EX_OPENBSD64 | EX_DRAGONFLYBSD64)) != 0;
}
/* FreeBSD fails when having some frames as having unwinding info and some not.
* (It hangs in unittests for std.datetime.)
* g++ on FreeBSD does not generate mixed frames, while g++ on OSX and Linux does.
*/
assert(!(usednteh & ~(EHtry | EHcleanup)));
return (usednteh & (EHtry | EHcleanup)) ||
(config.exe & (EX_FREEBSD | EX_FREEBSD64 | EX_OPENBSD | EX_OPENBSD64 | EX_DRAGONFLYBSD64)) && config.useExceptions;
}
SYMIDX MAP_SEG2SYMIDX(int seg) { return SegData[seg].SDsymidx; }
int OFFSET_FAC() { return REGSIZE(); }
int dwarf_getsegment(const(char)* name, int align_, int flags)
{
if (config.objfmt == OBJ_ELF)
return Obj.getsegment(name, null, flags, 0, align_ * 4);
else if (config.objfmt == OBJ_MACH)
return Obj.getsegment(name, "__DWARF", align_ * 2, flags);
else
assert(0);
}
int dwarf_getsegment_alloc(const(char)* name, const(char)* suffix, int align_)
{
return Obj.getsegment(name, suffix, SHT_PROGBITS, SHF_ALLOC, align_ * 4);
}
int dwarf_except_table_alloc(Symbol *s)
{
//printf("dwarf_except_table_alloc('%s')\n", s.Sident.ptr);
if (config.objfmt == OBJ_ELF)
{
/* If `s` is in a COMDAT, then this table needs to go into
* a unique section, which then gets added to the COMDAT group
* associated with `s`.
*/
seg_data *pseg = SegData[s.Sseg];
if (pseg.SDassocseg)
{
const(char)* suffix = s.Sident.ptr; // cpp_mangle(s);
segidx_t tableseg = Obj.getsegment(".gcc_except_table.", suffix, SHT_PROGBITS, SHF_ALLOC|SHF_GROUP, 1);
addSegmentToComdat(tableseg, s.Sseg);
return tableseg;
}
else
return dwarf_getsegment_alloc(".gcc_except_table", null, 1);
}
else if (config.objfmt == OBJ_MACH)
{
return getsegment2(except_table_seg, "__gcc_except_tab", "__TEXT", 2, S_REGULAR);
}
else
assert(0);
}
int dwarf_eh_frame_alloc()
{
if (config.objfmt == OBJ_ELF)
return dwarf_getsegment_alloc(".eh_frame", null, I64 ? 2 : 1);
else if (config.objfmt == OBJ_MACH)
{
int seg = getsegment2(eh_frame_seg, "__eh_frame", "__TEXT", I64 ? 3 : 2,
S_COALESCED | S_ATTR_NO_TOC | S_ATTR_STRIP_STATIC_SYMS | S_ATTR_LIVE_SUPPORT);
/* Generate symbol for it to use for fixups
*/
if (!eh_frame_sym)
{
type *t = tspvoid;
t.Tcount++;
type_setmangle(&t, mTYman_sys); // no leading '_' for mangled name
eh_frame_sym = symbol_name("EH_frame0", SCstatic, t);
Obj.pubdef(seg, eh_frame_sym, 0);
symbol_keep(eh_frame_sym);
}
return seg;
}
else
assert(0);
}
// machobj.c
enum RELaddr = 0; // straight address
enum RELrel = 1; // relative to location to be fixed up
void dwarf_addrel(int seg, targ_size_t offset, int targseg, targ_size_t val = 0)
{
if (config.objfmt == OBJ_ELF)
Obj.addrel(seg, offset, I64 ? R_X86_64_32 : R_386_32, cast(int)MAP_SEG2SYMIDX(targseg), val);
else if (config.objfmt == OBJ_MACH)
Obj.addrel(seg, offset, cast(Symbol*) null, targseg, RELaddr, cast(int)val);
else
assert(0);
}
void dwarf_addrel64(int seg, targ_size_t offset, int targseg, targ_size_t val)
{
if (config.objfmt == OBJ_ELF)
Obj.addrel(seg, offset, R_X86_64_64, cast(int)MAP_SEG2SYMIDX(targseg), val);
else if (config.objfmt == OBJ_MACH)
Obj.addrel(seg, offset, null, targseg, RELaddr, cast(uint)val);
else
assert(0);
}
void dwarf_appreladdr(int seg, OutBuffer *buf, int targseg, targ_size_t val)
{
if (I64)
{
if (config.objfmt == OBJ_ELF)
{
dwarf_addrel64(seg, buf.length(), targseg, val);
buf.write64(0);
}
else if (config.objfmt == OBJ_MACH)
{
dwarf_addrel64(seg, buf.length(), targseg, 0);
buf.write64(val);
}
else
assert(0);
}
else
{
dwarf_addrel(seg, buf.length(), targseg, 0);
buf.write32(cast(uint)val);
}
}
void dwarf_apprel32(int seg, OutBuffer *buf, int targseg, targ_size_t val)
{
dwarf_addrel(seg, buf.length(), targseg, I64 ? val : 0);
buf.write32(I64 ? 0 : cast(uint)val);
}
void append_addr(OutBuffer *buf, targ_size_t addr)
{
if (I64)
buf.write64(addr);
else
buf.write32(cast(uint)addr);
}
/************************ DWARF DEBUG OUTPUT ********************************/
// Dwarf Symbolic Debugging Information
// CFA = value of the stack pointer at the call site in the previous frame
struct CFA_reg
{
int offset; // offset from CFA
}
// Current CFA state for .debug_frame
struct CFA_state
{
size_t location;
int reg; // CFA register number
int offset; // CFA register offset
CFA_reg[17] regstates; // register states
}
/***********************
* Convert CPU register number to Dwarf register number.
* Params:
* reg = CPU register
* Returns:
* dwarf register
*/
int dwarf_regno(int reg)
{
assert(reg < NUMGENREGS);
if (I32)
{
if (config.objfmt == OBJ_MACH)
{
if (reg == BP || reg == SP)
reg ^= BP ^ SP; // swap EBP and ESP register values for OSX (!)
}
return reg;
}
else
{
assert(I64);
/* See https://software.intel.com/sites/default/files/article/402129/mpx-linux64-abi.pdf
* Figure 3.3.8 pg. 62
* R8..15 : 8..15
* XMM0..15 : 17..32
* ST0..7 : 33..40
* MM0..7 : 41..48
* XMM16..31 : 67..82
*/
static immutable int[8] to_amd64_reg_map =
// AX CX DX BX SP BP SI DI
[ 0, 2, 1, 3, 7, 6, 4, 5 ];
return reg < 8 ? to_amd64_reg_map[reg] : reg;
}
}
private __gshared
{
CFA_state CFA_state_init_32 = // initial CFA state as defined by CIE
{ 0, // location
-1, // register
4, // offset
[ { 0 }, // 0: EAX
{ 0 }, // 1: ECX
{ 0 }, // 2: EDX
{ 0 }, // 3: EBX
{ 0 }, // 4: ESP
{ 0 }, // 5: EBP
{ 0 }, // 6: ESI
{ 0 }, // 7: EDI
{ -4 }, // 8: EIP
]
};
CFA_state CFA_state_init_64 = // initial CFA state as defined by CIE
{ 0, // location
-1, // register
8, // offset
[ { 0 }, // 0: RAX
{ 0 }, // 1: RBX
{ 0 }, // 2: RCX
{ 0 }, // 3: RDX
{ 0 }, // 4: RSI
{ 0 }, // 5: RDI
{ 0 }, // 6: RBP
{ 0 }, // 7: RSP
{ 0 }, // 8: R8
{ 0 }, // 9: R9
{ 0 }, // 10: R10
{ 0 }, // 11: R11
{ 0 }, // 12: R12
{ 0 }, // 13: R13
{ 0 }, // 14: R14
{ 0 }, // 15: R15
{ -8 }, // 16: RIP
]
};
CFA_state CFA_state_current; // current CFA state
OutBuffer cfa_buf; // CFA instructions
}
/***********************************
* Set the location, i.e. the offset from the start
* of the function. It must always be greater than
* the current location.
* Params:
* location = offset from the start of the function
*/
void dwarf_CFA_set_loc(uint location)
{
assert(location >= CFA_state_current.location);
uint inc = cast(uint)(location - CFA_state_current.location);
if (inc <= 63)
cfa_buf.writeByte(DW_CFA_advance_loc + inc);
else if (inc <= 255)
{ cfa_buf.writeByte(DW_CFA_advance_loc1);
cfa_buf.writeByte(inc);
}
else if (inc <= 0xFFFF)
{ cfa_buf.writeByte(DW_CFA_advance_loc2);
cfa_buf.write16(inc);
}
else
{ cfa_buf.writeByte(DW_CFA_advance_loc4);
cfa_buf.write32(inc);
}
CFA_state_current.location = location;
}
/*******************************************
* Set the frame register, and its offset.
* Params:
* reg = machine register
* offset = offset from frame register
*/
void dwarf_CFA_set_reg_offset(int reg, int offset)
{
int dw_reg = dwarf_regno(reg);
if (dw_reg != CFA_state_current.reg)
{
if (offset == CFA_state_current.offset)
{
cfa_buf.writeByte(DW_CFA_def_cfa_register);
cfa_buf.writeuLEB128(dw_reg);
}
else if (offset < 0)
{
cfa_buf.writeByte(DW_CFA_def_cfa_sf);
cfa_buf.writeuLEB128(dw_reg);
cfa_buf.writesLEB128(offset / -OFFSET_FAC);
}
else
{
cfa_buf.writeByte(DW_CFA_def_cfa);
cfa_buf.writeuLEB128(dw_reg);
cfa_buf.writeuLEB128(offset);
}
}
else if (offset < 0)
{
cfa_buf.writeByte(DW_CFA_def_cfa_offset_sf);
cfa_buf.writesLEB128(offset / -OFFSET_FAC);
}
else
{
cfa_buf.writeByte(DW_CFA_def_cfa_offset);
cfa_buf.writeuLEB128(offset);
}
CFA_state_current.reg = dw_reg;
CFA_state_current.offset = offset;
}
/***********************************************
* Set reg to be at offset from frame register.
* Params:
* reg = machine register
* offset = offset from frame register
*/
void dwarf_CFA_offset(int reg, int offset)
{
int dw_reg = dwarf_regno(reg);
if (CFA_state_current.regstates[dw_reg].offset != offset)
{
if (offset <= 0)
{
cfa_buf.writeByte(DW_CFA_offset + dw_reg);
cfa_buf.writeuLEB128(offset / -OFFSET_FAC);
}
else
{
cfa_buf.writeByte(DW_CFA_offset_extended_sf);
cfa_buf.writeuLEB128(dw_reg);
cfa_buf.writesLEB128(offset / -OFFSET_FAC);
}
}
CFA_state_current.regstates[dw_reg].offset = offset;
}
/**************************************
* Set total size of arguments pushed on the stack.
* Params:
* sz = total size
*/
void dwarf_CFA_args_size(size_t sz)
{
cfa_buf.writeByte(DW_CFA_GNU_args_size);
cfa_buf.writeuLEB128(cast(uint)sz);
}
struct Section
{
segidx_t seg = 0;
IDXSEC secidx = 0;
OutBuffer *buf = null;
const(char)* name;
int flags = 0;
nothrow this (const(char)* n)
{
name = n;
if (config.objfmt == OBJ_MACH)
flags = S_ATTR_DEBUG;
else
flags = SHT_PROGBITS;
}
/* Allocate and initialize Section
*/
nothrow void initialize()
{
const segidx_t segi = dwarf_getsegment(name, 0, flags);
seg = segi;
secidx = SegData[segi].SDshtidx;
buf = SegData[segi].SDbuf;
buf.reserve(1000);
}
}
private __gshared
{
Section debug_pubnames;
Section debug_aranges;
Section debug_ranges;
Section debug_loc;
Section debug_abbrev;
Section debug_info;
Section debug_str;
Section debug_line;
const(char*) debug_frame_name()
{
if (config.objfmt == OBJ_MACH)
return "__debug_frame";
else if (config.objfmt == OBJ_ELF)
return ".debug_frame";
else return null;
}
/* DWARF 7.5.3: "Each declaration begins with an unsigned LEB128 number
* representing the abbreviation code itself."
*/
uint abbrevcode = 1;
AApair *abbrev_table;
int hasModname; // 1 if has DW_TAG_module
// .debug_info
AAchars *infoFileName_table;
AApair *type_table;
AApair *functype_table; // not sure why this cannot be combined with type_table
OutBuffer *functypebuf;
// .debug_line
size_t linebuf_filetab_end;
size_t lineHeaderLengthOffset;
AAchars* lineDirectories;
const byte line_base = -5;
const ubyte line_range = 14;
const ubyte opcode_base = 13;
public uint[TYMAX] typidx_tab;
}
void machDebugSectionsInit()
{
debug_pubnames = Section("__debug_pubnames");
debug_aranges = Section("__debug_aranges");
debug_ranges = Section("__debug_ranges");
debug_loc = Section("__debug_loc");
debug_abbrev = Section("__debug_abbrev");
debug_info = Section("__debug_info");
debug_str = Section("__debug_str");
// We use S_REGULAR to make sure the linker doesn't remove this section. Needed
// for filenames and line numbers in backtraces.
debug_line = Section("__debug_line");
debug_line.flags = S_REGULAR;
}
void elfDebugSectionsInit()
{
debug_pubnames = Section(".debug_pubnames");
debug_aranges = Section(".debug_aranges");
debug_ranges = Section(".debug_ranges");
debug_loc = Section(".debug_loc");
debug_abbrev = Section(".debug_abbrev");
debug_info = Section(".debug_info");
debug_str = Section(".debug_str");
debug_line = Section(".debug_line");
}
/*****************************************
* Replace the bytes in `buf` from the `offset` by `data`.
*
* Params:
* buf = buffer where `data` will be written
* offset = offset of the bytes in `buf` to replace
* data = bytes to write
*/
extern(D) void rewrite(T)(OutBuffer* buf, size_t offset, T data)
{
*(cast(T*)&buf.buf[offset]) = data;
}
alias rewrite32 = rewrite!uint;
alias rewrite64 = rewrite!ulong;
/*****************************************
* Append .debug_frame header to buf.
* Params:
* buf = write raw data here
*/
void writeDebugFrameHeader(OutBuffer *buf)
{
void writeDebugFrameHeader(ubyte dversion)()
{
struct DebugFrameHeader
{
align (1):
uint length;
uint CIE_id = 0xFFFFFFFF;
ubyte version_ = dversion;
ubyte augmentation;
static if (dversion >= 4)
{
ubyte address_size = 4;
ubyte segment_selector_size;
}
ubyte code_alignment_factor = 1;
ubyte data_alignment_factor = 0x80;
ubyte return_address_register = 8;
ubyte[11] opcodes =
[
DW_CFA_def_cfa, 4, 4, // r4,4 [r7,8]
DW_CFA_offset + 8, 1, // r8,1 [r16,1]
DW_CFA_nop, DW_CFA_nop,
DW_CFA_nop, DW_CFA_nop, // 64 padding
DW_CFA_nop, DW_CFA_nop, // 64 padding
];
}
static if (dversion == 3)
static assert(DebugFrameHeader.sizeof == 24);
else static if (dversion == 4)
static assert(DebugFrameHeader.sizeof == 26);
else
static assert(0);
auto dfh = DebugFrameHeader.init;
dfh.data_alignment_factor -= OFFSET_FAC;
if (I64)
{
dfh.length = DebugFrameHeader.sizeof - 4;
dfh.return_address_register = 16; // (-8)
dfh.opcodes[1] = 7; // RSP
dfh.opcodes[2] = 8;
dfh.opcodes[3] = DW_CFA_offset + 16; // RIP
}
else
{
dfh.length = DebugFrameHeader.sizeof - 8;
}
buf.writen(&dfh, dfh.length + 4);
}
if (config.dwarf == 3)
writeDebugFrameHeader!3();
else
writeDebugFrameHeader!4();
}
/*****************************************
* Append .eh_frame header to buf.
* Almost identical to .debug_frame
* Params:
* dfseg = SegData[] index for .eh_frame
* buf = write raw data here
* personality = "__dmd_personality_v0"
* ehunwind = will have EH unwind table
* Returns:
* offset of start of this header
* See_Also:
* https://refspecs.linuxfoundation.org/LSB_3.0.0/LSB-PDA/LSB-PDA/ehframechpt.html
*/
private uint writeEhFrameHeader(IDXSEC dfseg, OutBuffer *buf, Symbol *personality, bool ehunwind)
{
/* Augmentation string:
* z = first character, means Augmentation Data field is present
* eh = EH Data field is present
* P = Augmentation Data contains 2 args:
* 1. encoding of 2nd arg
* 2. address of personality routine
* L = Augmentation Data contains 1 arg:
* 1. the encoding used for Augmentation Data in FDE
* Augmentation Data in FDE:
* 1. address of LSDA (gcc_except_table)
* R = Augmentation Data contains 1 arg:
* 1. encoding of addresses in FDE
* Non-EH code: "zR"
* EH code: "zPLR"
*/
const uint startsize = cast(uint)buf.length();
// Length of CIE, not including padding
const uint cielen = 4 + 4 + 1 +
(ehunwind ? 5 : 3) +
1 + 1 + 1 +
(ehunwind ? 8 : 2) +
5;
const uint pad = -cielen & (I64 ? 7 : 3); // pad to addressing unit size boundary
const uint length = cielen + pad - 4;
buf.reserve(length + 4);
buf.write32(length); // length of CIE, not including length and extended length fields
buf.write32(0); // CIE ID
buf.writeByten(1); // version_
if (ehunwind)
buf.write("zPLR".ptr, 5); // Augmentation String
else
buf.writen("zR".ptr, 3);
// not present: EH Data: 4 bytes for I32, 8 bytes for I64
buf.writeByten(1); // code alignment factor
buf.writeByten(cast(ubyte)(0x80 - OFFSET_FAC)); // data alignment factor (I64 ? -8 : -4)
buf.writeByten(I64 ? 16 : 8); // return address register
if (ehunwind)
{
ubyte personality_pointer_encoding = 0;
ubyte LSDA_pointer_encoding = 0;
ubyte address_pointer_encoding = 0;
if (config.objfmt == OBJ_ELF)
{
personality_pointer_encoding = config.flags3 & CFG3pic
? DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4
: DW_EH_PE_absptr | DW_EH_PE_udata4;
LSDA_pointer_encoding = config.flags3 & CFG3pic
? DW_EH_PE_pcrel | DW_EH_PE_sdata4
: DW_EH_PE_absptr | DW_EH_PE_udata4;
address_pointer_encoding =
DW_EH_PE_pcrel | DW_EH_PE_sdata4;
}
else if (config.objfmt == OBJ_MACH)
{
personality_pointer_encoding =
DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
LSDA_pointer_encoding =
DW_EH_PE_pcrel | DW_EH_PE_ptr;
address_pointer_encoding =
DW_EH_PE_pcrel | DW_EH_PE_ptr;
}
buf.writeByten(7); // Augmentation Length
buf.writeByten(personality_pointer_encoding); // P: personality routine address encoding
/* MACHOBJ 64: pcrel 1 length 2 extern 1 RELOC_GOT
* 32: [4] address x0013 pcrel 0 length 2 value xfc type 4 RELOC_LOCAL_SECTDIFF
* [5] address x0000 pcrel 0 length 2 value xc7 type 1 RELOC_PAIR
*/
if (config.objfmt == OBJ_ELF)
elf_dwarf_reftoident(dfseg, buf.length(), personality, 0);
else
mach_dwarf_reftoident(dfseg, buf.length(), personality, 0);
buf.writeByten(LSDA_pointer_encoding); // L: address encoding for LSDA in FDE
buf.writeByten(address_pointer_encoding); // R: encoding of addresses in FDE
}
else
{
buf.writeByten(1); // Augmentation Length
if (config.objfmt == OBJ_ELF)
buf.writeByten(DW_EH_PE_pcrel | DW_EH_PE_sdata4); // R: encoding of addresses in FDE
else if (config.objfmt == OBJ_MACH)
buf.writeByten(DW_EH_PE_pcrel | DW_EH_PE_ptr); // R: encoding of addresses in FDE
}
// Set CFA beginning state at function entry point
if (I64)
{
buf.writeByten(DW_CFA_def_cfa); // DEF_CFA r7,8 RSP is at offset 8
buf.writeByten(7); // r7 is RSP
buf.writeByten(8);
buf.writeByten(DW_CFA_offset + 16); // OFFSET r16,1 RIP is at -8*1[RSP]
buf.writeByten(1);
}
else
{
buf.writeByten(DW_CFA_def_cfa); // DEF_CFA ESP,4
buf.writeByten(cast(ubyte)dwarf_regno(SP));
buf.writeByten(4);
buf.writeByten(DW_CFA_offset + 8); // OFFSET r8,1
buf.writeByten(1);
}
for (uint i = 0; i < pad; ++i)
buf.writeByten(DW_CFA_nop);
assert(startsize + length + 4 == buf.length());
return startsize;
}
/*********************************************
* Generate function's Frame Description Entry into .debug_frame
* Params:
* dfseg = SegData[] index for .debug_frame
* sfunc = the function
*/
void writeDebugFrameFDE(IDXSEC dfseg, Symbol *sfunc)
{
if (I64)
{
static struct DebugFrameFDE64
{
align (1):
uint length;
uint CIE_pointer;
ulong initial_location;
ulong address_range;
}
static assert(DebugFrameFDE64.sizeof == 24);
__gshared DebugFrameFDE64 debugFrameFDE64 =
{
20, // length
0, // CIE_pointer
0, // initial_location
0, // address_range
};
// Pad to 8 byte boundary
for (uint n = (-cfa_buf.length() & 7); n; n--)
cfa_buf.writeByte(DW_CFA_nop);
debugFrameFDE64.length = 20 + cast(uint)cfa_buf.length();
debugFrameFDE64.address_range = sfunc.Ssize;
// Do we need this?
//debugFrameFDE64.initial_location = sfunc.Soffset;
OutBuffer *debug_frame_buf = SegData[dfseg].SDbuf;
uint debug_frame_buf_offset = cast(uint)debug_frame_buf.length();
debug_frame_buf.reserve(1000);
debug_frame_buf.writen(&debugFrameFDE64,debugFrameFDE64.sizeof);
debug_frame_buf.write(cfa_buf[]);
if (config.objfmt == OBJ_ELF)
// Absolute address for debug_frame, relative offset for eh_frame
dwarf_addrel(dfseg,debug_frame_buf_offset + 4,dfseg,0);
dwarf_addrel64(dfseg,debug_frame_buf_offset + 8,sfunc.Sseg,0);
}
else
{
static struct DebugFrameFDE32
{
align (1):
uint length;
uint CIE_pointer;
uint initial_location;
uint address_range;
}
static assert(DebugFrameFDE32.sizeof == 16);
__gshared DebugFrameFDE32 debugFrameFDE32 =
{
12, // length
0, // CIE_pointer
0, // initial_location
0, // address_range
};
// Pad to 4 byte boundary
for (uint n = (-cfa_buf.length() & 3); n; n--)
cfa_buf.writeByte(DW_CFA_nop);
debugFrameFDE32.length = 12 + cast(uint)cfa_buf.length();
debugFrameFDE32.address_range = cast(uint)sfunc.Ssize;
// Do we need this?
//debugFrameFDE32.initial_location = sfunc.Soffset;
OutBuffer *debug_frame_buf = SegData[dfseg].SDbuf;
uint debug_frame_buf_offset = cast(uint)debug_frame_buf.length();
debug_frame_buf.reserve(1000);
debug_frame_buf.writen(&debugFrameFDE32,debugFrameFDE32.sizeof);
debug_frame_buf.write(cfa_buf[]);
if (config.objfmt == OBJ_ELF)
// Absolute address for debug_frame, relative offset for eh_frame
dwarf_addrel(dfseg,debug_frame_buf_offset + 4,dfseg,0);
dwarf_addrel(dfseg,debug_frame_buf_offset + 8,sfunc.Sseg,0);
}
}
/*********************************************
* Append function's FDE (Frame Description Entry) to .eh_frame
* Params:
* dfseg = SegData[] index for .eh_frame
* sfunc = the function
* ehunwind = will have EH unwind table
* CIE_offset = offset of enclosing CIE
*/
void writeEhFrameFDE(IDXSEC dfseg, Symbol *sfunc, bool ehunwind, uint CIE_offset)
{
OutBuffer *buf = SegData[dfseg].SDbuf;
const uint startsize = cast(uint)buf.length();
Symbol *fdesym;
if (config.objfmt == OBJ_MACH)
{
/* Create symbol named "funcname.eh" for the start of the FDE
*/
const size_t len = strlen(getSymName(sfunc));
char *name = cast(char *)malloc(len + 3 + 1);
if (!name)
err_nomem();
memcpy(name, getSymName(sfunc), len);
memcpy(name + len, ".eh".ptr, 3 + 1);
fdesym = symbol_name(name, SCglobal, tspvoid);
Obj.pubdef(dfseg, fdesym, startsize);
symbol_keep(fdesym);
free(name);
}
if (sfunc.ty() & mTYnaked)
{
/* Do not have info on naked functions. Assume they are set up as:
* push RBP
* mov RSP,RSP
*/
int off = 2 * REGSIZE;
dwarf_CFA_set_loc(1);
dwarf_CFA_set_reg_offset(SP, off);
dwarf_CFA_offset(BP, -off);
dwarf_CFA_set_loc(I64 ? 4 : 3);
dwarf_CFA_set_reg_offset(BP, off);
}
// Length of FDE, not including padding
uint fdelen = 0;
if (config.objfmt == OBJ_ELF)
{
fdelen = 4 + 4
+ 4 + 4
+ (ehunwind ? 5 : 1) + cast(uint)cfa_buf.length();
}
else if (config.objfmt == OBJ_MACH)
{
fdelen = 4 + 4
+ (I64 ? 8 + 8 : 4 + 4) // PC_Begin + PC_Range
+ (ehunwind ? (I64 ? 9 : 5) : 1) + cast(uint)cfa_buf.length();
}
const uint pad = -fdelen & (I64 ? 7 : 3); // pad to addressing unit size boundary
const uint length = fdelen + pad - 4;
buf.reserve(length + 4);
buf.write32(length); // Length (no Extended Length)
buf.write32((startsize + 4) - CIE_offset); // CIE Pointer
int fixup = 0;
if (config.objfmt == OBJ_ELF)
{
fixup = I64 ? R_X86_64_PC32 : R_386_PC32;
buf.write32(cast(uint)(I64 ? 0 : sfunc.Soffset)); // address of function
Obj.addrel(dfseg, startsize + 8, fixup, cast(int)MAP_SEG2SYMIDX(sfunc.Sseg), sfunc.Soffset);
//Obj.reftoident(dfseg, startsize + 8, sfunc, 0, CFpc32 | CFoff); // PC_begin
buf.write32(cast(uint)sfunc.Ssize); // PC Range
}
if (config.objfmt == OBJ_MACH)
{
dwarf_eh_frame_fixup(dfseg, buf.length(), sfunc, 0, fdesym);
if (I64)
buf.write64(sfunc.Ssize); // PC Range
else
buf.write32(cast(uint)sfunc.Ssize); // PC Range
}
if (ehunwind)
{
int etseg = dwarf_except_table_alloc(sfunc);
if (config.objfmt == OBJ_ELF)
{
buf.writeByten(4); // Augmentation Data Length
buf.write32(I64 ? 0 : sfunc.Sfunc.LSDAoffset); // address of LSDA (".gcc_except_table")
if (config.flags3 & CFG3pic)
{
Obj.addrel(dfseg, buf.length() - 4, fixup, cast(int)MAP_SEG2SYMIDX(etseg), sfunc.Sfunc.LSDAoffset);
}
else
dwarf_addrel(dfseg, buf.length() - 4, etseg, sfunc.Sfunc.LSDAoffset); // and the fixup
}
if (config.objfmt == OBJ_MACH)
{
buf.writeByten(I64 ? 8 : 4); // Augmentation Data Length
dwarf_eh_frame_fixup(dfseg, buf.length(), sfunc.Sfunc.LSDAsym, 0, fdesym);
}
}
else
buf.writeByten(0); // Augmentation Data Length
buf.write(cfa_buf[]);
for (uint i = 0; i < pad; ++i)
buf.writeByten(DW_CFA_nop);