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dwarfdbginf.d
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dwarfdbginf.d
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/**
* Compiler implementation of the
* $(LINK2 http://www.dlang.org, D programming language).
*
* Copyright: Copyright (C) 1999-2019 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
*/
// Emit Dwarf symbolic debug info
/*
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;
version(Windows)
{
extern (C) char* getcwd(char* buffer, size_t maxlen);
extern (C) int* _errno(); // not the multi-threaded version
}
else
{
import core.sys.posix.unistd : getcwd;
}
import dmd.backend.cc;
import dmd.backend.cdef;
import dmd.backend.code;
import dmd.backend.code_x86;
import dmd.backend.mem;
import dmd.backend.dlist;
import dmd.backend.el;
import dmd.backend.global;
import dmd.backend.obj;
import dmd.backend.oper;
import dmd.backend.outbuf;
import dmd.backend.ty;
import dmd.backend.type;
static if (ELFOBJ || MACHOBJ)
{
import dmd.backend.aarray;
static if (ELFOBJ)
import dmd.backend.melf;
static if (MACHOBJ)
import dmd.backend.mach;
import dmd.backend.dwarf;
import dmd.backend.dwarf2;
extern (C++):
int REGSIZE();
__gshared
{
extern int seg_count;
static if (MACHOBJ)
{
int except_table_seg = 0; // __gcc_except_tab segment
int except_table_num = 0; // sequence number for GCC_except_table%d symbols
int eh_frame_seg = 0; // __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
static if (ELFOBJ)
{
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);
}
Symbol* getRtlsymPersonality();
private Outbuffer *reset_symbuf; // 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_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_DRAGONFLYBSD64)) && config.useExceptions;
}
static if (ELFOBJ)
SYMIDX MAP_SEG2SYMIDX(int seg) { return SegData[seg].SDsymidx; }
else
SYMIDX MAP_SEG2SYMIDX(int seg) { assert(0); }
int OFFSET_FAC() { return REGSIZE(); }
int dwarf_getsegment(const(char)* name, int align_, int flags)
{
static if (ELFOBJ)
return Obj.getsegment(name, null, flags, 0, align_ * 4);
else static if (MACHOBJ)
return Obj.getsegment(name, "__DWARF", align_ * 2, flags);
else
assert(0);
}
static if (ELFOBJ)
{
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);
static if (ELFOBJ)
{
/* 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 static if (MACHOBJ)
{
int seg = Obj.getsegment("__gcc_except_tab", "__TEXT", 2, S_REGULAR);
except_table_seg = seg;
return seg;
}
else
assert(0);
}
int dwarf_eh_frame_alloc()
{
static if (ELFOBJ)
return dwarf_getsegment_alloc(".eh_frame", null, I64 ? 2 : 1);
else static if (MACHOBJ)
{
int seg = Obj.getsegment("__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);
eh_frame_seg = seg;
}
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)
{
static if (ELFOBJ)
Obj.addrel(seg, offset, I64 ? R_X86_64_32 : R_386_32, MAP_SEG2SYMIDX(targseg), val);
else static if (MACHOBJ)
Obj.addrel(seg, offset, null, targseg, RELaddr, cast(uint)val);
else
assert(0);
}
void dwarf_addrel64(int seg, targ_size_t offset, int targseg, targ_size_t val)
{
static if (ELFOBJ)
Obj.addrel(seg, offset, R_X86_64_64, MAP_SEG2SYMIDX(targseg), val);
else static if (MACHOBJ)
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)
{
dwarf_addrel64(seg, buf.size(), targseg, val);
buf.write64(0);
}
else
{
dwarf_addrel(seg, buf.size(), targseg, 0);
buf.write32(cast(uint)val);
}
}
void dwarf_apprel32(int seg, Outbuffer *buf, int targseg, targ_size_t val)
{
dwarf_addrel(seg, buf.size(), 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)
{
static if (MACHOBJ)
{
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.writeWord(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;
IDXSEC secidx;
Outbuffer *buf;
const(char)* name;
int flags;
/* Allocate and initialize Section
*/
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
{
static if (MACHOBJ)
{
Section debug_pubnames = { 0,0,null, "__debug_pubnames", S_ATTR_DEBUG };
Section debug_aranges = { 0,0,null, "__debug_aranges", S_ATTR_DEBUG };
Section debug_ranges = { 0,0,null, "__debug_ranges", S_ATTR_DEBUG };
Section debug_loc = { 0,0,null, "__debug_loc", S_ATTR_DEBUG };
Section debug_abbrev = { 0,0,null, "__debug_abbrev", S_ATTR_DEBUG };
Section debug_info = { 0,0,null, "__debug_info", S_ATTR_DEBUG };
Section debug_str = { 0,0,null, "__debug_str", S_ATTR_DEBUG };
// We use S_REGULAR to make sure the linker doesn't remove this section. Needed
// for filenames and line numbers in backtraces.
Section debug_line = { 0,0,null, "__debug_line", S_REGULAR };
}
else static if (ELFOBJ)
{
Section debug_pubnames = { 0,0,null, ".debug_pubnames", SHT_PROGBITS };
Section debug_aranges = { 0,0,null, ".debug_aranges", SHT_PROGBITS };
Section debug_ranges = { 0,0,null, ".debug_ranges", SHT_PROGBITS };
Section debug_loc = { 0,0,null, ".debug_loc", SHT_PROGBITS };
Section debug_abbrev = { 0,0,null, ".debug_abbrev", SHT_PROGBITS };
Section debug_info = { 0,0,null, ".debug_info", SHT_PROGBITS };
Section debug_str = { 0,0,null, ".debug_str", SHT_PROGBITS };
Section debug_line = { 0,0,null, ".debug_line", SHT_PROGBITS };
}
static if (MACHOBJ)
const char* debug_frame_name = "__debug_frame";
else static if (ELFOBJ)
const char* debug_frame_name = ".debug_frame";
/* 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;
struct DebugInfoHeader
{
align (1):
uint total_length;
ushort version_;
uint abbrev_offset;
ubyte address_size;
}
// Workaround https://issues.dlang.org/show_bug.cgi?id=16563
// Struct alignment is ignored due to 2.072 regression.
static assert((DebugInfoHeader.alignof == 1 && DebugInfoHeader.sizeof == 11) ||
(DebugInfoHeader.alignof == 4 && DebugInfoHeader.sizeof == 12));
DebugInfoHeader debuginfo_init =
{ 0, // total_length
3, // version_
0, // abbrev_offset
4 // address_size
};
DebugInfoHeader debuginfo;
// .debug_line
size_t linebuf_filetab_end;
struct DebugLineHeader
{
align (1):
uint total_length;
ushort version_;
uint prologue_length;
ubyte minimum_instruction_length;
ubyte default_is_stmt;
byte line_base;
ubyte line_range;
ubyte opcode_base;
ubyte[9] standard_opcode_lengths;
}
static assert(DebugLineHeader.sizeof == 24);
DebugLineHeader debugline_init =
{ 0, // total_length
2, // version_
0, // prologue_length
1, // minimum_instruction_length
true, // default_is_stmt
-5, // line_base
14, // line_range
10, // opcode_base
[ 0,1,1,1,1,0,0,0,1 ]
};
DebugLineHeader debugline;
public uint[TYMAX] typidx_tab;
}
/*****************************************
* Append .debug_frame header to buf.
* Params:
* buf = write raw data here
*/
void writeDebugFrameHeader(Outbuffer *buf)
{
static struct DebugFrameHeader
{
align (1):
uint length;
uint CIE_id;
ubyte version_;
ubyte augmentation;
ubyte code_alignment_factor;
ubyte data_alignment_factor;
ubyte return_address_register;
ubyte[11] opcodes;
}
static assert(DebugFrameHeader.sizeof == 24);
__gshared DebugFrameHeader debugFrameHeader =
{ 16, // length
0xFFFFFFFF, // CIE_id
1, // version_
0, // augmentation
1, // code alignment factor
0x7C, // data alignment factor (-4)
8, // return address register
[
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
]
};
if (I64)
{ debugFrameHeader.length = 20;
debugFrameHeader.data_alignment_factor = 0x78; // (-8)
debugFrameHeader.return_address_register = 16;
debugFrameHeader.opcodes[1] = 7; // RSP
debugFrameHeader.opcodes[2] = 8;
debugFrameHeader.opcodes[3] = DW_CFA_offset + 16; // RIP
}
assert(debugFrameHeader.data_alignment_factor == 0x80 - OFFSET_FAC);
buf.writen(&debugFrameHeader,debugFrameHeader.length + 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.size();
// 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)
{
static if (ELFOBJ)
{
const ubyte 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;
const ubyte LSDA_pointer_encoding = config.flags3 & CFG3pic
? DW_EH_PE_pcrel | DW_EH_PE_sdata4
: DW_EH_PE_absptr | DW_EH_PE_udata4;
const ubyte address_pointer_encoding =
DW_EH_PE_pcrel | DW_EH_PE_sdata4;
}
else static if (MACHOBJ)
{
const ubyte personality_pointer_encoding =
DW_EH_PE_indirect | DW_EH_PE_pcrel | DW_EH_PE_sdata4;
const ubyte LSDA_pointer_encoding =
DW_EH_PE_pcrel | DW_EH_PE_ptr;
const ubyte 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
*/
dwarf_reftoident(dfseg, buf.size(), 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
static if (ELFOBJ)
buf.writeByten(DW_EH_PE_pcrel | DW_EH_PE_sdata4); // R: encoding of addresses in FDE
static if (MACHOBJ)
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.size());
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.size() & 7); n; n--)
cfa_buf.writeByte(DW_CFA_nop);
debugFrameFDE64.length = 20 + cast(uint)cfa_buf.size();
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.p - debug_frame_buf.buf);
debug_frame_buf.reserve(1000);
debug_frame_buf.writen(&debugFrameFDE64,debugFrameFDE64.sizeof);
debug_frame_buf.write(&cfa_buf);
static if (ELFOBJ)
// 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.size() & 3); n; n--)
cfa_buf.writeByte(DW_CFA_nop);
debugFrameFDE32.length = 12 + cast(uint)cfa_buf.size();
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.p - debug_frame_buf.buf);
debug_frame_buf.reserve(1000);
debug_frame_buf.writen(&debugFrameFDE32,debugFrameFDE32.sizeof);
debug_frame_buf.write(&cfa_buf);
static if (ELFOBJ)
// 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.size();
static if (MACHOBJ)
{
/* Create symbol named "funcname.eh" for the start of the FDE
*/
Symbol *fdesym;
{
const size_t len = strlen(sfunc.Sident.ptr);
char *name = cast(char *)malloc(len + 3 + 1);
if (!name)
err_nomem();
memcpy(name, sfunc.Sident.ptr, len);
memcpy(name + len, ".eh".ptr, 3 + 1);
fdesym = symbol_name(name, SCglobal, tspvoid);
Obj.pubdef(dfseg, fdesym, startsize);
symbol_keep(fdesym);
}
}
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
static if (ELFOBJ)
const uint fdelen = 4 + 4
+ 4 + 4
+ (ehunwind ? 5 : 1) + cast(uint)cfa_buf.size();
else static if (MACHOBJ)
const uint fdelen = 4 + 4
+ (I64 ? 8 + 8 : 4 + 4) // PC_Begin + PC_Range
+ (ehunwind ? (I64 ? 9 : 5) : 1) + cast(uint)cfa_buf.size();
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
static if (ELFOBJ)
{
int 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, 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
}
else static if (MACHOBJ)
{
dwarf_eh_frame_fixup(dfseg, buf.size(), sfunc, 0, fdesym);
if (I64)
buf.write64(sfunc.Ssize); // PC Range
else
buf.write32(cast(uint)sfunc.Ssize); // PC Range
}
else
assert(0);
if (ehunwind)
{
int etseg = dwarf_except_table_alloc(sfunc);
static if (ELFOBJ)
{
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.size() - 4, fixup, MAP_SEG2SYMIDX(etseg), sfunc.Sfunc.LSDAoffset);
}
else
dwarf_addrel(dfseg, buf.size() - 4, etseg, sfunc.Sfunc.LSDAoffset); // and the fixup
}
else static if (MACHOBJ)
{
buf.writeByten(I64 ? 8 : 4); // Augmentation Data Length
dwarf_eh_frame_fixup(dfseg, buf.size(), 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);
assert(startsize + length + 4 == buf.size());
}
void dwarf_initfile(const(char)* filename)
{
if (config.ehmethod == EHmethod.EH_DWARF)
{
static if (MACHOBJ)
{
except_table_seg = 0;
except_table_num = 0;
eh_frame_seg = 0;
eh_frame_sym = null;
}
CIE_offset_unwind = ~0;
CIE_offset_no_unwind = ~0;
//dwarf_except_table_alloc();
dwarf_eh_frame_alloc();