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#include "readDwarf.h"
#include <assert.h>
#include <unordered_map>
#include <array>
#include <windows.h>
#include "PEImage.h"
#include "dwarf.h"
#include "mspdb.h"
extern "C" {
#include "mscvpdb.h"
}
static Location mkInReg(unsigned reg)
{
Location l;
l.type = Location::InReg;
l.reg = reg;
return l;
}
static Location mkAbs(int off)
{
Location l;
l.type = Location::Abs;
l.off = off;
return l;
}
static Location mkRegRel(int reg, int off)
{
Location l;
l.type = Location::RegRel;
l.reg = reg;
l.off = off;
return l;
}
Location decodeLocation(const DWARF_Attribute& attr, const Location* frameBase)
{
static Location invalid = { Location::Invalid };
if (attr.type == Const)
return mkAbs(attr.cons);
if (attr.type != ExprLoc)
return invalid;
byte* p = attr.expr.ptr;
Location stack[256];
int stackDepth = 0;
for (;;)
{
if (p >= attr.expr.ptr + attr.expr.len)
break;
int op = *p++;
if (op == 0)
break;
switch (op)
{
case DW_OP_reg0: case DW_OP_reg1: case DW_OP_reg2: case DW_OP_reg3:
case DW_OP_reg4: case DW_OP_reg5: case DW_OP_reg6: case DW_OP_reg7:
case DW_OP_reg8: case DW_OP_reg9: case DW_OP_reg10: case DW_OP_reg11:
case DW_OP_reg12: case DW_OP_reg13: case DW_OP_reg14: case DW_OP_reg15:
case DW_OP_reg16: case DW_OP_reg17: case DW_OP_reg18: case DW_OP_reg19:
case DW_OP_reg20: case DW_OP_reg21: case DW_OP_reg22: case DW_OP_reg23:
case DW_OP_reg24: case DW_OP_reg25: case DW_OP_reg26: case DW_OP_reg27:
case DW_OP_reg28: case DW_OP_reg29: case DW_OP_reg30: case DW_OP_reg31:
stack[stackDepth++] = mkInReg(op - DW_OP_reg0);
break;
case DW_OP_regx:
stack[stackDepth++] = mkInReg(LEB128(p));
break;
case DW_OP_const1u: stack[stackDepth++] = mkAbs(*p); break;
case DW_OP_const2u: stack[stackDepth++] = mkAbs(RD2(p)); break;
case DW_OP_const4u: stack[stackDepth++] = mkAbs(RD4(p)); break;
case DW_OP_const1s: stack[stackDepth++] = mkAbs((char)*p); break;
case DW_OP_const2s: stack[stackDepth++] = mkAbs((short)RD2(p)); break;
case DW_OP_const4s: stack[stackDepth++] = mkAbs((int)RD4(p)); break;
case DW_OP_constu: stack[stackDepth++] = mkAbs(LEB128(p)); break;
case DW_OP_consts: stack[stackDepth++] = mkAbs(SLEB128(p)); break;
case DW_OP_plus_uconst:
if (stack[stackDepth - 1].is_inreg())
return invalid;
stack[stackDepth - 1].off += LEB128(p);
break;
case DW_OP_lit0: case DW_OP_lit1: case DW_OP_lit2: case DW_OP_lit3:
case DW_OP_lit4: case DW_OP_lit5: case DW_OP_lit6: case DW_OP_lit7:
case DW_OP_lit8: case DW_OP_lit9: case DW_OP_lit10: case DW_OP_lit11:
case DW_OP_lit12: case DW_OP_lit13: case DW_OP_lit14: case DW_OP_lit15:
case DW_OP_lit16: case DW_OP_lit17: case DW_OP_lit18: case DW_OP_lit19:
case DW_OP_lit20: case DW_OP_lit21: case DW_OP_lit22: case DW_OP_lit23:
stack[stackDepth++] = mkAbs(op - DW_OP_lit0);
break;
case DW_OP_breg0: case DW_OP_breg1: case DW_OP_breg2: case DW_OP_breg3:
case DW_OP_breg4: case DW_OP_breg5: case DW_OP_breg6: case DW_OP_breg7:
case DW_OP_breg8: case DW_OP_breg9: case DW_OP_breg10: case DW_OP_breg11:
case DW_OP_breg12: case DW_OP_breg13: case DW_OP_breg14: case DW_OP_breg15:
case DW_OP_breg16: case DW_OP_breg17: case DW_OP_breg18: case DW_OP_breg19:
case DW_OP_breg20: case DW_OP_breg21: case DW_OP_breg22: case DW_OP_breg23:
case DW_OP_breg24: case DW_OP_breg25: case DW_OP_breg26: case DW_OP_breg27:
case DW_OP_breg28: case DW_OP_breg29: case DW_OP_breg30: case DW_OP_breg31:
stack[stackDepth++] = mkRegRel(op - DW_OP_breg0, SLEB128(p));
break;
case DW_OP_bregx:
{
unsigned reg = LEB128(p);
stack[stackDepth++] = mkRegRel(reg, SLEB128(p));
} break;
case DW_OP_abs: case DW_OP_neg: case DW_OP_not:
{
Location& op1 = stack[stackDepth - 1];
if (!op1.is_abs())
return invalid;
switch (op)
{
case DW_OP_abs: op1 = mkAbs(abs(op1.off)); break;
case DW_OP_neg: op1 = mkAbs(-op1.off); break;
case DW_OP_not: op1 = mkAbs(~op1.off); break;
}
} break;
case DW_OP_plus: // op2 + op1
{
Location& op1 = stack[stackDepth - 1];
Location& op2 = stack[stackDepth - 2];
// Can add only two offsets or a regrel and an offset.
if (op2.is_regrel() && op1.is_abs())
op2 = mkRegRel(op2.reg, op2.off + op1.off);
else if (op2.is_abs() && op1.is_regrel())
op2 = mkRegRel(op1.reg, op2.off + op1.off);
else if (op2.is_abs() && op1.is_abs())
op2 = mkAbs(op2.off + op1.off);
else
return invalid;
--stackDepth;
} break;
case DW_OP_minus: // op2 - op1
{
Location& op1 = stack[stackDepth - 1];
Location& op2 = stack[stackDepth - 2];
if (op2.is_regrel() && op1.is_regrel() && op2.reg == op1.reg)
op2 = mkAbs(0); // X - X == 0
else if (op2.is_regrel() && op1.is_abs())
op2 = mkRegRel(op2.reg, op2.off - op1.off);
else if (op2.is_abs() && op1.is_abs())
op2 = mkAbs(op2.off - op1.off);
else
return invalid;
--stackDepth;
} break;
case DW_OP_mul:
{
Location& op1 = stack[stackDepth - 1];
Location& op2 = stack[stackDepth - 2];
if ((op1.is_abs() && op1.off == 0) || (op2.is_abs() && op2.off == 0))
op2 = mkAbs(0); // X * 0 == 0
else if (op1.is_abs() && op2.is_abs())
op2 = mkAbs(op1.off * op2.off);
else
return invalid;
--stackDepth;
} break;
case DW_OP_and:
{
Location& op1 = stack[stackDepth - 1];
Location& op2 = stack[stackDepth - 2];
if ((op1.is_abs() && op1.off == 0) || (op2.is_abs() && op2.off == 0))
op2 = mkAbs(0); // X & 0 == 0
else if (op1.is_abs() && op2.is_abs())
op2 = mkAbs(op1.off & op2.off);
else
return invalid;
--stackDepth;
} break;
case DW_OP_div: case DW_OP_mod: case DW_OP_shl:
case DW_OP_shr: case DW_OP_shra: case DW_OP_or:
case DW_OP_xor:
case DW_OP_eq: case DW_OP_ge: case DW_OP_gt:
case DW_OP_le: case DW_OP_lt: case DW_OP_ne:
{
Location& op1 = stack[stackDepth - 1];
Location& op2 = stack[stackDepth - 2];
if (!op1.is_abs() || !op2.is_abs()) // can't combine unless both are constants
return invalid;
switch (op)
{
case DW_OP_div: op2.off = op2.off / op1.off; break;
case DW_OP_mod: op2.off = op2.off % op1.off; break;
case DW_OP_shl: op2.off = op2.off << op1.off; break;
case DW_OP_shr: op2.off = op2.off >> op1.off; break;
case DW_OP_shra: op2.off = op2.off >> op1.off; break;
case DW_OP_or: op2.off = op2.off | op1.off; break;
case DW_OP_xor: op2.off = op2.off ^ op1.off; break;
case DW_OP_eq: op2.off = op2.off == op1.off; break;
case DW_OP_ge: op2.off = op2.off >= op1.off; break;
case DW_OP_gt: op2.off = op2.off > op1.off; break;
case DW_OP_le: op2.off = op2.off <= op1.off; break;
case DW_OP_lt: op2.off = op2.off < op1.off; break;
case DW_OP_ne: op2.off = op2.off != op1.off; break;
}
--stackDepth;
} break;
case DW_OP_fbreg:
{
if (!frameBase)
return invalid;
Location loc;
if (frameBase->is_inreg()) // ok in frame base specification, per DWARF4 spec #3.3.5
loc = mkRegRel(frameBase->reg, SLEB128(p));
else if (frameBase->is_regrel())
loc = mkRegRel(frameBase->reg, frameBase->off + SLEB128(p));
else
return invalid;
stack[stackDepth++] = loc;
} break;
case DW_OP_dup: stack[stackDepth] = stack[stackDepth - 1]; stackDepth++; break;
case DW_OP_drop: stackDepth--; break;
case DW_OP_over: stack[stackDepth] = stack[stackDepth - 2]; stackDepth++; break;
case DW_OP_pick: stack[stackDepth++] = stack[*p]; break;
case DW_OP_swap: { Location tmp = stack[stackDepth - 1]; stack[stackDepth - 1] = stack[stackDepth - 2]; stack[stackDepth - 2] = tmp; } break;
case DW_OP_rot: { Location tmp = stack[stackDepth - 1]; stack[stackDepth - 1] = stack[stackDepth - 2]; stack[stackDepth - 2] = stack[stackDepth - 3]; stack[stackDepth - 3] = tmp; } break;
case DW_OP_addr:
stack[stackDepth++] = mkAbs(RD4(p)); // TODO: 64-bit
break;
case DW_OP_skip:
{
unsigned off = RD2(p);
p = p + off;
} break;
case DW_OP_bra:
{
Location& op1 = stack[stackDepth - 1];
if (!op1.is_abs())
return invalid;
if (op1.off != 0)
{
unsigned off = RD2(p);
p = p + off;
}
--stackDepth;
} break;
case DW_OP_nop:
break;
case DW_OP_deref:
case DW_OP_deref_size:
case DW_OP_push_object_address:
case DW_OP_call2:
case DW_OP_call4:
case DW_OP_form_tls_address:
case DW_OP_call_frame_cfa:
case DW_OP_call_ref:
case DW_OP_bit_piece:
case DW_OP_implicit_value:
case DW_OP_stack_value:
default:
return invalid;
}
}
assert(stackDepth > 0);
return stack[0];
}
// declare hasher for pair<T1,T2>
namespace std
{
template<typename T1, typename T2>
struct hash<std::pair<T1, T2>>
{
size_t operator()(const std::pair<T1, T2>& t) const
{
return std::hash<T1>()(t.first) ^ std::hash<T2>()(t.second);
}
};
}
typedef std::unordered_map<std::pair<unsigned, unsigned>, byte*> abbrevMap_t;
static PEImage* img;
static abbrevMap_t abbrevMap;
void DIECursor::setContext(PEImage* img_)
{
img = img_;
abbrevMap.clear();
}
DIECursor::DIECursor(DWARF_CompilationUnit* cu_, byte* ptr_)
{
cu = cu_;
ptr = ptr_;
level = 0;
hasChild = false;
sibling = 0;
}
bool DIECursor::readSibling(DWARF_InfoData& id)
{
if (sibling)
{
// use sibling pointer, if available
ptr = sibling;
hasChild = false;
}
else if (hasChild)
{
int currLevel = level;
level = currLevel + 1;
hasChild = false;
DWARF_InfoData dummy;
// read untill we pop back to the level we were at
while (level > currLevel)
readNext(dummy);
}
return readNext(id, true);
}
DIECursor DIECursor::getSubtreeCursor()
{
if (hasChild)
{
DIECursor subtree = *this;
subtree.level = 0;
subtree.hasChild = false;
return subtree;
}
else // Return invalid cursor
{
DIECursor subtree = *this;
subtree.level = -1;
return subtree;
}
}
bool DIECursor::readNext(DWARF_InfoData& id, bool stopAtNull)
{
id.clear();
if (hasChild)
++level;
for (;;)
{
if (level == -1)
return false; // we were already at the end of the subtree
if (ptr >= ((byte*)cu + sizeof(cu->unit_length) + cu->unit_length))
return false; // root of the tree does not have a null terminator, but we know the length
id.entryPtr = ptr;
id.entryOff = ptr - (byte*)cu;
id.code = LEB128(ptr);
if (id.code == 0)
{
--level; // pop up one level
if (stopAtNull)
{
hasChild = false;
return false;
}
continue; // read the next DIE
}
break;
}
byte* abbrev = getDWARFAbbrev(cu->debug_abbrev_offset, id.code);
assert(abbrev);
if (!abbrev)
return false;
id.abbrev = abbrev;
id.tag = LEB128(abbrev);
id.hasChild = *abbrev++;
int attr, form;
for (;;)
{
attr = LEB128(abbrev);
form = LEB128(abbrev);
if (attr == 0 && form == 0)
break;
while (form == DW_FORM_indirect)
form = LEB128(ptr);
DWARF_Attribute a;
switch (form)
{
case DW_FORM_addr: a.type = Addr; a.addr = (unsigned long)RDsize(ptr, cu->address_size); break;
case DW_FORM_block: a.type = Block; a.block.len = LEB128(ptr); a.block.ptr = ptr; ptr += a.block.len; break;
case DW_FORM_block1: a.type = Block; a.block.len = *ptr++; a.block.ptr = ptr; ptr += a.block.len; break;
case DW_FORM_block2: a.type = Block; a.block.len = RD2(ptr); a.block.ptr = ptr; ptr += a.block.len; break;
case DW_FORM_block4: a.type = Block; a.block.len = RD4(ptr); a.block.ptr = ptr; ptr += a.block.len; break;
case DW_FORM_data1: a.type = Const; a.cons = *ptr++; break;
case DW_FORM_data2: a.type = Const; a.cons = RD2(ptr); break;
case DW_FORM_data4: a.type = Const; a.cons = RD4(ptr); break;
case DW_FORM_data8: a.type = Const; a.cons = RD8(ptr); break;
case DW_FORM_sdata: a.type = Const; a.cons = SLEB128(ptr); break;
case DW_FORM_udata: a.type = Const; a.cons = LEB128(ptr); break;
case DW_FORM_string: a.type = String; a.string = (const char*)ptr; ptr += strlen(a.string) + 1; break;
case DW_FORM_strp: a.type = String; a.string = (const char*)(img->debug_str + RDsize(ptr, cu->isDWARF64() ? 8 : 4)); break;
case DW_FORM_flag: a.type = Flag; a.flag = (*ptr++ != 0); break;
case DW_FORM_flag_present: a.type = Flag; a.flag = true; break;
case DW_FORM_ref1: a.type = Ref; a.ref = (byte*)cu + *ptr++; break;
case DW_FORM_ref2: a.type = Ref; a.ref = (byte*)cu + RD2(ptr); break;
case DW_FORM_ref4: a.type = Ref; a.ref = (byte*)cu + RD4(ptr); break;
case DW_FORM_ref8: a.type = Ref; a.ref = (byte*)cu + RD8(ptr); break;
case DW_FORM_ref_udata: a.type = Ref; a.ref = (byte*)cu + LEB128(ptr); break;
case DW_FORM_ref_addr: a.type = Ref; a.ref = (byte*)img->debug_info + (cu->isDWARF64() ? RD8(ptr) : RD4(ptr)); break;
case DW_FORM_ref_sig8: a.type = Invalid; ptr += 8; break;
case DW_FORM_exprloc: a.type = ExprLoc; a.expr.len = LEB128(ptr); a.expr.ptr = ptr; ptr += a.expr.len; break;
case DW_FORM_sec_offset: a.type = SecOffset; a.sec_offset = cu->isDWARF64() ? RD8(ptr) : RD4(ptr); break;
case DW_FORM_indirect:
default: assert(false && "Unsupported DWARF attribute form"); return false;
}
switch (attr)
{
case DW_AT_byte_size:
assert(a.type == Const || a.type == Ref || a.type == ExprLoc);
if (a.type == Const) // TODO: other types not supported yet
id.byte_size = a.cons;
break;
case DW_AT_sibling: assert(a.type == Ref); id.sibling = a.ref; break;
case DW_AT_encoding: assert(a.type == Const); id.encoding = a.cons; break;
case DW_AT_name: assert(a.type == String); id.name = a.string; break;
case DW_AT_MIPS_linkage_name: assert(a.type == String); id.linkage_name = a.string; break;
case DW_AT_comp_dir: assert(a.type == String); id.dir = a.string; break;
case DW_AT_low_pc: assert(a.type == Addr); id.pclo = a.addr; break;
case DW_AT_high_pc:
if (a.type == Addr)
id.pchi = a.addr;
else if (a.type == Const)
id.pchi = id.pclo + a.cons;
else
assert(false);
break;
case DW_AT_ranges:
if (a.type == SecOffset)
id.ranges = a.sec_offset;
else if (a.type == Const)
id.ranges = a.cons;
else
assert(false);
break;
case DW_AT_type: assert(a.type == Ref); id.type = a.ref; break;
case DW_AT_inline: assert(a.type == Const); id.inlined = a.cons; break;
case DW_AT_external: assert(a.type == Flag); id.external = a.flag; break;
case DW_AT_upper_bound:
assert(a.type == Const || a.type == Ref || a.type == ExprLoc);
if (a.type == Const) // TODO: other types not supported yet
id.upper_bound = a.cons;
break;
case DW_AT_lower_bound:
assert(a.type == Const || a.type == Ref || a.type == ExprLoc);
if (a.type == Const) // TODO: other types not supported yet
id.lower_bound = a.cons;
break;
case DW_AT_containing_type: assert(a.type == Ref); id.containing_type = a.ref; break;
case DW_AT_specification: assert(a.type == Ref); id.specification = a.ref; break;
case DW_AT_data_member_location: id.member_location = a; break;
case DW_AT_location: id.location = a; break;
case DW_AT_frame_base: id.frame_base = a; break;
}
}
hasChild = id.hasChild != 0;
sibling = id.sibling;
return true;
}
byte* DIECursor::getDWARFAbbrev(unsigned off, unsigned findcode)
{
if (!img->debug_abbrev)
return 0;
std::pair<unsigned, unsigned> key = std::make_pair(off, findcode);
abbrevMap_t::iterator it = abbrevMap.find(key);
if (it != abbrevMap.end())
{
return it->second;
}
byte* p = (byte*)img->debug_abbrev + off;
byte* end = (byte*)img->debug_abbrev + img->debug_abbrev_length;
while (p < end)
{
int code = LEB128(p);
if (code == findcode)
{
abbrevMap.insert(std::make_pair(key, p));
return p;
}
if (code == 0)
return 0;
int tag = LEB128(p);
int hasChild = *p++;
// skip attributes
int attr, form;
do
{
attr = LEB128(p);
form = LEB128(p);
} while (attr || form);
}
return 0;
}
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