tools/wrk/deps/luajit/src/lj_gdbjit.c
/*
** Client for the GDB JIT API.
** Copyright (C) 2005-2013 Mike Pall. See Copyright Notice in luajit.h
*/
#define lj_gdbjit_c
#define LUA_CORE
#include "lj_obj.h"
#if LJ_HASJIT
#include "lj_gc.h"
#include "lj_err.h"
#include "lj_debug.h"
#include "lj_frame.h"
#include "lj_jit.h"
#include "lj_dispatch.h"
/* This is not compiled in by default.
** Enable with -DLUAJIT_USE_GDBJIT in the Makefile and recompile everything.
*/
#ifdef LUAJIT_USE_GDBJIT
/* The GDB JIT API allows JIT compilers to pass debug information about
** JIT-compiled code back to GDB. You need at least GDB 7.0 or higher
** to see it in action.
**
** This is a passive API, so it works even when not running under GDB
** or when attaching to an already running process. Alas, this implies
** enabling it always has a non-negligible overhead -- do not use in
** release mode!
**
** The LuaJIT GDB JIT client is rather minimal at the moment. It gives
** each trace a symbol name and adds a source location and frame unwind
** information. Obviously LuaJIT itself and any embedding C application
** should be compiled with debug symbols, too (see the Makefile).
**
** Traces are named TRACE_1, TRACE_2, ... these correspond to the trace
** numbers from -jv or -jdump. Use "break TRACE_1" or "tbreak TRACE_1" etc.
** to set breakpoints on specific traces (even ahead of their creation).
**
** The source location for each trace allows listing the corresponding
** source lines with the GDB command "list" (but only if the Lua source
** has been loaded from a file). Currently this is always set to the
** location where the trace has been started.
**
** Frame unwind information can be inspected with the GDB command
** "info frame". This also allows proper backtraces across JIT-compiled
** code with the GDB command "bt".
**
** You probably want to add the following settings to a .gdbinit file
** (or add them to ~/.gdbinit):
** set disassembly-flavor intel
** set breakpoint pending on
**
** Here's a sample GDB session:
** ------------------------------------------------------------------------
$ cat >x.lua
for outer=1,100 do
for inner=1,100 do end
end
^D
$ luajit -jv x.lua
[TRACE 1 x.lua:2]
[TRACE 2 (1/3) x.lua:1 -> 1]
$ gdb --quiet --args luajit x.lua
(gdb) tbreak TRACE_1
Function "TRACE_1" not defined.
Temporary breakpoint 1 (TRACE_1) pending.
(gdb) run
Starting program: luajit x.lua
Temporary breakpoint 1, TRACE_1 () at x.lua:2
2 for inner=1,100 do end
(gdb) list
1 for outer=1,100 do
2 for inner=1,100 do end
3 end
(gdb) bt
#0 TRACE_1 () at x.lua:2
#1 0x08053690 in lua_pcall [...]
[...]
#7 0x0806ff90 in main [...]
(gdb) disass TRACE_1
Dump of assembler code for function TRACE_1:
0xf7fd9fba <TRACE_1+0>: mov DWORD PTR ds:0xf7e0e2a0,0x1
0xf7fd9fc4 <TRACE_1+10>: movsd xmm7,QWORD PTR [edx+0x20]
[...]
0xf7fd9ff8 <TRACE_1+62>: jmp 0xf7fd2014
End of assembler dump.
(gdb) tbreak TRACE_2
Function "TRACE_2" not defined.
Temporary breakpoint 2 (TRACE_2) pending.
(gdb) cont
Continuing.
Temporary breakpoint 2, TRACE_2 () at x.lua:1
1 for outer=1,100 do
(gdb) info frame
Stack level 0, frame at 0xffffd7c0:
eip = 0xf7fd9f60 in TRACE_2 (x.lua:1); saved eip 0x8053690
called by frame at 0xffffd7e0
source language unknown.
Arglist at 0xffffd78c, args:
Locals at 0xffffd78c, Previous frame's sp is 0xffffd7c0
Saved registers:
ebx at 0xffffd7ac, ebp at 0xffffd7b8, esi at 0xffffd7b0, edi at 0xffffd7b4,
eip at 0xffffd7bc
(gdb)
** ------------------------------------------------------------------------
*/
/* -- GDB JIT API --------------------------------------------------------- */
/* GDB JIT actions. */
enum {
GDBJIT_NOACTION = 0,
GDBJIT_REGISTER,
GDBJIT_UNREGISTER
};
/* GDB JIT entry. */
typedef struct GDBJITentry {
struct GDBJITentry *next_entry;
struct GDBJITentry *prev_entry;
const char *symfile_addr;
uint64_t symfile_size;
} GDBJITentry;
/* GDB JIT descriptor. */
typedef struct GDBJITdesc {
uint32_t version;
uint32_t action_flag;
GDBJITentry *relevant_entry;
GDBJITentry *first_entry;
} GDBJITdesc;
GDBJITdesc __jit_debug_descriptor = {
1, GDBJIT_NOACTION, NULL, NULL
};
/* GDB sets a breakpoint at this function. */
void LJ_NOINLINE __jit_debug_register_code()
{
__asm__ __volatile__("");
};
/* -- In-memory ELF object definitions ------------------------------------ */
/* ELF definitions. */
typedef struct ELFheader {
uint8_t emagic[4];
uint8_t eclass;
uint8_t eendian;
uint8_t eversion;
uint8_t eosabi;
uint8_t eabiversion;
uint8_t epad[7];
uint16_t type;
uint16_t machine;
uint32_t version;
uintptr_t entry;
uintptr_t phofs;
uintptr_t shofs;
uint32_t flags;
uint16_t ehsize;
uint16_t phentsize;
uint16_t phnum;
uint16_t shentsize;
uint16_t shnum;
uint16_t shstridx;
} ELFheader;
typedef struct ELFsectheader {
uint32_t name;
uint32_t type;
uintptr_t flags;
uintptr_t addr;
uintptr_t ofs;
uintptr_t size;
uint32_t link;
uint32_t info;
uintptr_t align;
uintptr_t entsize;
} ELFsectheader;
#define ELFSECT_IDX_ABS 0xfff1
enum {
ELFSECT_TYPE_PROGBITS = 1,
ELFSECT_TYPE_SYMTAB = 2,
ELFSECT_TYPE_STRTAB = 3,
ELFSECT_TYPE_NOBITS = 8
};
#define ELFSECT_FLAGS_WRITE 1
#define ELFSECT_FLAGS_ALLOC 2
#define ELFSECT_FLAGS_EXEC 4
typedef struct ELFsymbol {
#if LJ_64
uint32_t name;
uint8_t info;
uint8_t other;
uint16_t sectidx;
uintptr_t value;
uint64_t size;
#else
uint32_t name;
uintptr_t value;
uint32_t size;
uint8_t info;
uint8_t other;
uint16_t sectidx;
#endif
} ELFsymbol;
enum {
ELFSYM_TYPE_FUNC = 2,
ELFSYM_TYPE_FILE = 4,
ELFSYM_BIND_LOCAL = 0 << 4,
ELFSYM_BIND_GLOBAL = 1 << 4,
};
/* DWARF definitions. */
#define DW_CIE_VERSION 1
enum {
DW_CFA_nop = 0x0,
DW_CFA_offset_extended = 0x5,
DW_CFA_def_cfa = 0xc,
DW_CFA_def_cfa_offset = 0xe,
DW_CFA_offset_extended_sf = 0x11,
DW_CFA_advance_loc = 0x40,
DW_CFA_offset = 0x80
};
enum {
DW_EH_PE_udata4 = 3,
DW_EH_PE_textrel = 0x20
};
enum {
DW_TAG_compile_unit = 0x11
};
enum {
DW_children_no = 0,
DW_children_yes = 1
};
enum {
DW_AT_name = 0x03,
DW_AT_stmt_list = 0x10,
DW_AT_low_pc = 0x11,
DW_AT_high_pc = 0x12
};
enum {
DW_FORM_addr = 0x01,
DW_FORM_data4 = 0x06,
DW_FORM_string = 0x08
};
enum {
DW_LNS_extended_op = 0,
DW_LNS_copy = 1,
DW_LNS_advance_pc = 2,
DW_LNS_advance_line = 3
};
enum {
DW_LNE_end_sequence = 1,
DW_LNE_set_address = 2
};
enum {
#if LJ_TARGET_X86
DW_REG_AX, DW_REG_CX, DW_REG_DX, DW_REG_BX,
DW_REG_SP, DW_REG_BP, DW_REG_SI, DW_REG_DI,
DW_REG_RA,
#elif LJ_TARGET_X64
/* Yes, the order is strange, but correct. */
DW_REG_AX, DW_REG_DX, DW_REG_CX, DW_REG_BX,
DW_REG_SI, DW_REG_DI, DW_REG_BP, DW_REG_SP,
DW_REG_8, DW_REG_9, DW_REG_10, DW_REG_11,
DW_REG_12, DW_REG_13, DW_REG_14, DW_REG_15,
DW_REG_RA,
#elif LJ_TARGET_ARM
DW_REG_SP = 13,
DW_REG_RA = 14,
#elif LJ_TARGET_PPC
DW_REG_SP = 1,
DW_REG_RA = 65,
DW_REG_CR = 70,
#elif LJ_TARGET_MIPS
DW_REG_SP = 29,
DW_REG_RA = 31,
#else
#error "Unsupported target architecture"
#endif
};
/* Minimal list of sections for the in-memory ELF object. */
enum {
GDBJIT_SECT_NULL,
GDBJIT_SECT_text,
GDBJIT_SECT_eh_frame,
GDBJIT_SECT_shstrtab,
GDBJIT_SECT_strtab,
GDBJIT_SECT_symtab,
GDBJIT_SECT_debug_info,
GDBJIT_SECT_debug_abbrev,
GDBJIT_SECT_debug_line,
GDBJIT_SECT__MAX
};
enum {
GDBJIT_SYM_UNDEF,
GDBJIT_SYM_FILE,
GDBJIT_SYM_FUNC,
GDBJIT_SYM__MAX
};
/* In-memory ELF object. */
typedef struct GDBJITobj {
ELFheader hdr; /* ELF header. */
ELFsectheader sect[GDBJIT_SECT__MAX]; /* ELF sections. */
ELFsymbol sym[GDBJIT_SYM__MAX]; /* ELF symbol table. */
uint8_t space[4096]; /* Space for various section data. */
} GDBJITobj;
/* Combined structure for GDB JIT entry and ELF object. */
typedef struct GDBJITentryobj {
GDBJITentry entry;
size_t sz;
GDBJITobj obj;
} GDBJITentryobj;
/* Template for in-memory ELF header. */
static const ELFheader elfhdr_template = {
.emagic = { 0x7f, 'E', 'L', 'F' },
.eclass = LJ_64 ? 2 : 1,
.eendian = LJ_ENDIAN_SELECT(1, 2),
.eversion = 1,
#if LJ_TARGET_LINUX
.eosabi = 0, /* Nope, it's not 3. */
#elif defined(__FreeBSD__)
.eosabi = 9,
#elif defined(__NetBSD__)
.eosabi = 2,
#elif defined(__OpenBSD__)
.eosabi = 12,
#elif (defined(__sun__) && defined(__svr4__))
.eosabi = 6,
#else
.eosabi = 0,
#endif
.eabiversion = 0,
.epad = { 0, 0, 0, 0, 0, 0, 0 },
.type = 1,
#if LJ_TARGET_X86
.machine = 3,
#elif LJ_TARGET_X64
.machine = 62,
#elif LJ_TARGET_ARM
.machine = 40,
#elif LJ_TARGET_PPC
.machine = 20,
#elif LJ_TARGET_MIPS
.machine = 8,
#else
#error "Unsupported target architecture"
#endif
.version = 1,
.entry = 0,
.phofs = 0,
.shofs = offsetof(GDBJITobj, sect),
.flags = 0,
.ehsize = sizeof(ELFheader),
.phentsize = 0,
.phnum = 0,
.shentsize = sizeof(ELFsectheader),
.shnum = GDBJIT_SECT__MAX,
.shstridx = GDBJIT_SECT_shstrtab
};
/* -- In-memory ELF object generation ------------------------------------- */
/* Context for generating the ELF object for the GDB JIT API. */
typedef struct GDBJITctx {
uint8_t *p; /* Pointer to next address in obj.space. */
uint8_t *startp; /* Pointer to start address in obj.space. */
GCtrace *T; /* Generate symbols for this trace. */
uintptr_t mcaddr; /* Machine code address. */
MSize szmcode; /* Size of machine code. */
MSize spadjp; /* Stack adjustment for parent trace or interpreter. */
MSize spadj; /* Stack adjustment for trace itself. */
BCLine lineno; /* Starting line number. */
const char *filename; /* Starting file name. */
size_t objsize; /* Final size of ELF object. */
GDBJITobj obj; /* In-memory ELF object. */
} GDBJITctx;
/* Add a zero-terminated string. */
static uint32_t gdbjit_strz(GDBJITctx *ctx, const char *str)
{
uint8_t *p = ctx->p;
uint32_t ofs = (uint32_t)(p - ctx->startp);
do {
*p++ = (uint8_t)*str;
} while (*str++);
ctx->p = p;
return ofs;
}
/* Append a decimal number. */
static void gdbjit_catnum(GDBJITctx *ctx, uint32_t n)
{
if (n >= 10) { uint32_t m = n / 10; n = n % 10; gdbjit_catnum(ctx, m); }
*ctx->p++ = '0' + n;
}
/* Add a ULEB128 value. */
static void gdbjit_uleb128(GDBJITctx *ctx, uint32_t v)
{
uint8_t *p = ctx->p;
for (; v >= 0x80; v >>= 7)
*p++ = (uint8_t)((v & 0x7f) | 0x80);
*p++ = (uint8_t)v;
ctx->p = p;
}
/* Add a SLEB128 value. */
static void gdbjit_sleb128(GDBJITctx *ctx, int32_t v)
{
uint8_t *p = ctx->p;
for (; (uint32_t)(v+0x40) >= 0x80; v >>= 7)
*p++ = (uint8_t)((v & 0x7f) | 0x80);
*p++ = (uint8_t)(v & 0x7f);
ctx->p = p;
}
/* Shortcuts to generate DWARF structures. */
#define DB(x) (*p++ = (x))
#define DI8(x) (*(int8_t *)p = (x), p++)
#define DU16(x) (*(uint16_t *)p = (x), p += 2)
#define DU32(x) (*(uint32_t *)p = (x), p += 4)
#define DADDR(x) (*(uintptr_t *)p = (x), p += sizeof(uintptr_t))
#define DUV(x) (ctx->p = p, gdbjit_uleb128(ctx, (x)), p = ctx->p)
#define DSV(x) (ctx->p = p, gdbjit_sleb128(ctx, (x)), p = ctx->p)
#define DSTR(str) (ctx->p = p, gdbjit_strz(ctx, (str)), p = ctx->p)
#define DALIGNNOP(s) while ((uintptr_t)p & ((s)-1)) *p++ = DW_CFA_nop
#define DSECT(name, stmt) \
{ uint32_t *szp_##name = (uint32_t *)p; p += 4; stmt \
*szp_##name = (uint32_t)((p-(uint8_t *)szp_##name)-4); } \
/* Initialize ELF section headers. */
static void LJ_FASTCALL gdbjit_secthdr(GDBJITctx *ctx)
{
ELFsectheader *sect;
*ctx->p++ = '\0'; /* Empty string at start of string table. */
#define SECTDEF(id, tp, al) \
sect = &ctx->obj.sect[GDBJIT_SECT_##id]; \
sect->name = gdbjit_strz(ctx, "." #id); \
sect->type = ELFSECT_TYPE_##tp; \
sect->align = (al)
SECTDEF(text, NOBITS, 16);
sect->flags = ELFSECT_FLAGS_ALLOC|ELFSECT_FLAGS_EXEC;
sect->addr = ctx->mcaddr;
sect->ofs = 0;
sect->size = ctx->szmcode;
SECTDEF(eh_frame, PROGBITS, sizeof(uintptr_t));
sect->flags = ELFSECT_FLAGS_ALLOC;
SECTDEF(shstrtab, STRTAB, 1);
SECTDEF(strtab, STRTAB, 1);
SECTDEF(symtab, SYMTAB, sizeof(uintptr_t));
sect->ofs = offsetof(GDBJITobj, sym);
sect->size = sizeof(ctx->obj.sym);
sect->link = GDBJIT_SECT_strtab;
sect->entsize = sizeof(ELFsymbol);
sect->info = GDBJIT_SYM_FUNC;
SECTDEF(debug_info, PROGBITS, 1);
SECTDEF(debug_abbrev, PROGBITS, 1);
SECTDEF(debug_line, PROGBITS, 1);
#undef SECTDEF
}
/* Initialize symbol table. */
static void LJ_FASTCALL gdbjit_symtab(GDBJITctx *ctx)
{
ELFsymbol *sym;
*ctx->p++ = '\0'; /* Empty string at start of string table. */
sym = &ctx->obj.sym[GDBJIT_SYM_FILE];
sym->name = gdbjit_strz(ctx, "JIT mcode");
sym->sectidx = ELFSECT_IDX_ABS;
sym->info = ELFSYM_TYPE_FILE|ELFSYM_BIND_LOCAL;
sym = &ctx->obj.sym[GDBJIT_SYM_FUNC];
sym->name = gdbjit_strz(ctx, "TRACE_"); ctx->p--;
gdbjit_catnum(ctx, ctx->T->traceno); *ctx->p++ = '\0';
sym->sectidx = GDBJIT_SECT_text;
sym->value = 0;
sym->size = ctx->szmcode;
sym->info = ELFSYM_TYPE_FUNC|ELFSYM_BIND_GLOBAL;
}
/* Initialize .eh_frame section. */
static void LJ_FASTCALL gdbjit_ehframe(GDBJITctx *ctx)
{
uint8_t *p = ctx->p;
uint8_t *framep = p;
/* Emit DWARF EH CIE. */
DSECT(CIE,
DU32(0); /* Offset to CIE itself. */
DB(DW_CIE_VERSION);
DSTR("zR"); /* Augmentation. */
DUV(1); /* Code alignment factor. */
DSV(-(int32_t)sizeof(uintptr_t)); /* Data alignment factor. */
DB(DW_REG_RA); /* Return address register. */
DB(1); DB(DW_EH_PE_textrel|DW_EH_PE_udata4); /* Augmentation data. */
DB(DW_CFA_def_cfa); DUV(DW_REG_SP); DUV(sizeof(uintptr_t));
#if LJ_TARGET_PPC
DB(DW_CFA_offset_extended_sf); DB(DW_REG_RA); DSV(-1);
#else
DB(DW_CFA_offset|DW_REG_RA); DUV(1);
#endif
DALIGNNOP(sizeof(uintptr_t));
)
/* Emit DWARF EH FDE. */
DSECT(FDE,
DU32((uint32_t)(p-framep)); /* Offset to CIE. */
DU32(0); /* Machine code offset relative to .text. */
DU32(ctx->szmcode); /* Machine code length. */
DB(0); /* Augmentation data. */
/* Registers saved in CFRAME. */
#if LJ_TARGET_X86
DB(DW_CFA_offset|DW_REG_BP); DUV(2);
DB(DW_CFA_offset|DW_REG_DI); DUV(3);
DB(DW_CFA_offset|DW_REG_SI); DUV(4);
DB(DW_CFA_offset|DW_REG_BX); DUV(5);
#elif LJ_TARGET_X64
DB(DW_CFA_offset|DW_REG_BP); DUV(2);
DB(DW_CFA_offset|DW_REG_BX); DUV(3);
DB(DW_CFA_offset|DW_REG_15); DUV(4);
DB(DW_CFA_offset|DW_REG_14); DUV(5);
/* Extra registers saved for JIT-compiled code. */
DB(DW_CFA_offset|DW_REG_13); DUV(9);
DB(DW_CFA_offset|DW_REG_12); DUV(10);
#elif LJ_TARGET_ARM
{
int i;
for (i = 11; i >= 4; i--) { DB(DW_CFA_offset|i); DUV(2+(11-i)); }
}
#elif LJ_TARGET_PPC
{
int i;
DB(DW_CFA_offset_extended); DB(DW_REG_CR); DUV(55);
for (i = 14; i <= 31; i++) {
DB(DW_CFA_offset|i); DUV(37+(31-i));
DB(DW_CFA_offset|32|i); DUV(2+2*(31-i));
}
}
#elif LJ_TARGET_MIPS
{
int i;
DB(DW_CFA_offset|30); DUV(2);
for (i = 23; i >= 16; i--) { DB(DW_CFA_offset|i); DUV(26-i); }
for (i = 30; i >= 20; i -= 2) { DB(DW_CFA_offset|32|i); DUV(42-i); }
}
#else
#error "Unsupported target architecture"
#endif
if (ctx->spadjp != ctx->spadj) { /* Parent/interpreter stack frame size. */
DB(DW_CFA_def_cfa_offset); DUV(ctx->spadjp);
DB(DW_CFA_advance_loc|1); /* Only an approximation. */
}
DB(DW_CFA_def_cfa_offset); DUV(ctx->spadj); /* Trace stack frame size. */
DALIGNNOP(sizeof(uintptr_t));
)
ctx->p = p;
}
/* Initialize .debug_info section. */
static void LJ_FASTCALL gdbjit_debuginfo(GDBJITctx *ctx)
{
uint8_t *p = ctx->p;
DSECT(info,
DU16(2); /* DWARF version. */
DU32(0); /* Abbrev offset. */
DB(sizeof(uintptr_t)); /* Pointer size. */
DUV(1); /* Abbrev #1: DW_TAG_compile_unit. */
DSTR(ctx->filename); /* DW_AT_name. */
DADDR(ctx->mcaddr); /* DW_AT_low_pc. */
DADDR(ctx->mcaddr + ctx->szmcode); /* DW_AT_high_pc. */
DU32(0); /* DW_AT_stmt_list. */
)
ctx->p = p;
}
/* Initialize .debug_abbrev section. */
static void LJ_FASTCALL gdbjit_debugabbrev(GDBJITctx *ctx)
{
uint8_t *p = ctx->p;
/* Abbrev #1: DW_TAG_compile_unit. */
DUV(1); DUV(DW_TAG_compile_unit);
DB(DW_children_no);
DUV(DW_AT_name); DUV(DW_FORM_string);
DUV(DW_AT_low_pc); DUV(DW_FORM_addr);
DUV(DW_AT_high_pc); DUV(DW_FORM_addr);
DUV(DW_AT_stmt_list); DUV(DW_FORM_data4);
DB(0); DB(0);
ctx->p = p;
}
#define DLNE(op, s) (DB(DW_LNS_extended_op), DUV(1+(s)), DB((op)))
/* Initialize .debug_line section. */
static void LJ_FASTCALL gdbjit_debugline(GDBJITctx *ctx)
{
uint8_t *p = ctx->p;
DSECT(line,
DU16(2); /* DWARF version. */
DSECT(header,
DB(1); /* Minimum instruction length. */
DB(1); /* is_stmt. */
DI8(0); /* Line base for special opcodes. */
DB(2); /* Line range for special opcodes. */
DB(3+1); /* Opcode base at DW_LNS_advance_line+1. */
DB(0); DB(1); DB(1); /* Standard opcode lengths. */
/* Directory table. */
DB(0);
/* File name table. */
DSTR(ctx->filename); DUV(0); DUV(0); DUV(0);
DB(0);
)
DLNE(DW_LNE_set_address, sizeof(uintptr_t)); DADDR(ctx->mcaddr);
if (ctx->lineno) {
DB(DW_LNS_advance_line); DSV(ctx->lineno-1);
}
DB(DW_LNS_copy);
DB(DW_LNS_advance_pc); DUV(ctx->szmcode);
DLNE(DW_LNE_end_sequence, 0);
)
ctx->p = p;
}
#undef DLNE
/* Undef shortcuts. */
#undef DB
#undef DI8
#undef DU16
#undef DU32
#undef DADDR
#undef DUV
#undef DSV
#undef DSTR
#undef DALIGNNOP
#undef DSECT
/* Type of a section initializer callback. */
typedef void (LJ_FASTCALL *GDBJITinitf)(GDBJITctx *ctx);
/* Call section initializer and set the section offset and size. */
static void gdbjit_initsect(GDBJITctx *ctx, int sect, GDBJITinitf initf)
{
ctx->startp = ctx->p;
ctx->obj.sect[sect].ofs = (uintptr_t)((char *)ctx->p - (char *)&ctx->obj);
initf(ctx);
ctx->obj.sect[sect].size = (uintptr_t)(ctx->p - ctx->startp);
}
#define SECTALIGN(p, a) \
((p) = (uint8_t *)(((uintptr_t)(p) + ((a)-1)) & ~(uintptr_t)((a)-1)))
/* Build in-memory ELF object. */
static void gdbjit_buildobj(GDBJITctx *ctx)
{
GDBJITobj *obj = &ctx->obj;
/* Fill in ELF header and clear structures. */
memcpy(&obj->hdr, &elfhdr_template, sizeof(ELFheader));
memset(&obj->sect, 0, sizeof(ELFsectheader)*GDBJIT_SECT__MAX);
memset(&obj->sym, 0, sizeof(ELFsymbol)*GDBJIT_SYM__MAX);
/* Initialize sections. */
ctx->p = obj->space;
gdbjit_initsect(ctx, GDBJIT_SECT_shstrtab, gdbjit_secthdr);
gdbjit_initsect(ctx, GDBJIT_SECT_strtab, gdbjit_symtab);
gdbjit_initsect(ctx, GDBJIT_SECT_debug_info, gdbjit_debuginfo);
gdbjit_initsect(ctx, GDBJIT_SECT_debug_abbrev, gdbjit_debugabbrev);
gdbjit_initsect(ctx, GDBJIT_SECT_debug_line, gdbjit_debugline);
SECTALIGN(ctx->p, sizeof(uintptr_t));
gdbjit_initsect(ctx, GDBJIT_SECT_eh_frame, gdbjit_ehframe);
ctx->objsize = (size_t)((char *)ctx->p - (char *)obj);
lua_assert(ctx->objsize < sizeof(GDBJITobj));
}
#undef SECTALIGN
/* -- Interface to GDB JIT API -------------------------------------------- */
/* Add new entry to GDB JIT symbol chain. */
static void gdbjit_newentry(lua_State *L, GDBJITctx *ctx)
{
/* Allocate memory for GDB JIT entry and ELF object. */
MSize sz = (MSize)(sizeof(GDBJITentryobj) - sizeof(GDBJITobj) + ctx->objsize);
GDBJITentryobj *eo = lj_mem_newt(L, sz, GDBJITentryobj);
memcpy(&eo->obj, &ctx->obj, ctx->objsize); /* Copy ELF object. */
eo->sz = sz;
ctx->T->gdbjit_entry = (void *)eo;
/* Link new entry to chain and register it. */
eo->entry.prev_entry = NULL;
eo->entry.next_entry = __jit_debug_descriptor.first_entry;
if (eo->entry.next_entry)
eo->entry.next_entry->prev_entry = &eo->entry;
eo->entry.symfile_addr = (const char *)&eo->obj;
eo->entry.symfile_size = ctx->objsize;
__jit_debug_descriptor.first_entry = &eo->entry;
__jit_debug_descriptor.relevant_entry = &eo->entry;
__jit_debug_descriptor.action_flag = GDBJIT_REGISTER;
__jit_debug_register_code();
}
/* Add debug info for newly compiled trace and notify GDB. */
void lj_gdbjit_addtrace(jit_State *J, GCtrace *T)
{
GDBJITctx ctx;
GCproto *pt = &gcref(T->startpt)->pt;
TraceNo parent = T->ir[REF_BASE].op1;
const BCIns *startpc = mref(T->startpc, const BCIns);
ctx.T = T;
ctx.mcaddr = (uintptr_t)T->mcode;
ctx.szmcode = T->szmcode;
ctx.spadjp = CFRAME_SIZE_JIT +
(MSize)(parent ? traceref(J, parent)->spadjust : 0);
ctx.spadj = CFRAME_SIZE_JIT + T->spadjust;
lua_assert(startpc >= proto_bc(pt) && startpc < proto_bc(pt) + pt->sizebc);
ctx.lineno = lj_debug_line(pt, proto_bcpos(pt, startpc));
ctx.filename = proto_chunknamestr(pt);
if (*ctx.filename == '@' || *ctx.filename == '=')
ctx.filename++;
else
ctx.filename = "(string)";
gdbjit_buildobj(&ctx);
gdbjit_newentry(J->L, &ctx);
}
/* Delete debug info for trace and notify GDB. */
void lj_gdbjit_deltrace(jit_State *J, GCtrace *T)
{
GDBJITentryobj *eo = (GDBJITentryobj *)T->gdbjit_entry;
if (eo) {
if (eo->entry.prev_entry)
eo->entry.prev_entry->next_entry = eo->entry.next_entry;
else
__jit_debug_descriptor.first_entry = eo->entry.next_entry;
if (eo->entry.next_entry)
eo->entry.next_entry->prev_entry = eo->entry.prev_entry;
__jit_debug_descriptor.relevant_entry = &eo->entry;
__jit_debug_descriptor.action_flag = GDBJIT_UNREGISTER;
__jit_debug_register_code();
lj_mem_free(J2G(J), eo, eo->sz);
}
}
#endif
#endif