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#pragma once
#include "Utils/Bitwise.h"
#include "Registers.h"
namespace code {
namespace dwarf {
/**
* Definitions of some useful DWARF constants.
*/
#define DW_CFA_advance_loc 0x40 // + delta
#define DW_CFA_offset 0x80 // + register
#define DW_CFA_restore 0xC0 // + register
#define DW_CFA_nop 0x00
#define DW_CFA_set_loc 0x01
#define DW_CFA_advance_loc1 0x02
#define DW_CFA_advance_loc2 0x03
#define DW_CFA_advance_loc4 0x04
#define DW_CFA_offset_extended 0x05
#define DW_CFA_restore_extended 0x06
#define DW_CFA_undefined 0x07
#define DW_CFA_same_value 0x08
#define DW_CFA_register 0x09
#define DW_CFA_remember_state 0x0a
#define DW_CFA_restore_state 0x0b
#define DW_CFA_def_cfa 0x0c
#define DW_CFA_def_cfa_register 0x0d
#define DW_CFA_def_cfa_offset 0x0e
#define DW_CFA_def_cfa_expression 0x0f
#define DW_CFA_expression 0x10
#define DW_CFA_offset_extended_sf 0x11
#define DW_CFA_def_cfa_sf 0x12
#define DW_CFA_def_cfa_offset_sf 0x13
#define DW_CFA_val_offset 0x14
#define DW_CFA_val_offset_sf 0x15
#define DW_CFA_val_expression 0x16
#define DW_EH_PE_absptr 0x00
// Extensions specific to AARCH64 (ARM64)
#define DW_CFA_AARCH64_negate_ra_state 0x2D
#define DW_CFA_AARCH64_negate_ra_state_with_pc 0x2C
/**
* Output to a buffer in DWARF compatible format.
*/
struct DStream {
byte *to;
nat pos;
nat len;
// Initialize.
DStream(byte *to, nat len) : to(to), pos(0), len(len) {}
DStream(byte *to, nat len, nat pos) : to(to), pos(pos), len(len) {}
// Did we run out of space?
bool overflow() const {
return pos > len;
}
// Write a byte.
void putByte(byte b) {
if (pos < len)
to[pos] = b;
pos++;
}
// Write a pointer.
void putPtr(const void *value) {
if (pos + sizeof(value) <= len) {
const void **d = (const void **)&to[pos];
*d = value;
}
pos += sizeof(value);
}
// Write an unsigned number (encoded as LEB128).
void putUNum(nat value) {
while (value >= 0x80) {
putByte((value & 0x7F) | 0x80);
value >>= 7;
}
putByte(value & 0x7F);
}
// Write a signed number (encoded as LEB128).
void putSNum(int value) {
nat src = value;
nat bits = value;
if (value < 0) {
bits = ~bits; // make 'positive'
bits <<= 1; // make sure to get at least one sign bit in the output.
}
while (bits >= 0x80) {
putByte((src & 0x7F) | 0x80);
src >>= 7;
bits >>= 7;
}
putByte(src & 0x7F);
}
// Write OP-codes.
void putOp(byte op) {
putByte(op);
}
void putSOp(byte op, int p1) {
putByte(op);
putSNum(p1);
}
void putUOp(byte op, nat p1) {
putByte(op);
putUNum(p1);
}
void putSOp(byte op, int p1, int p2) {
putByte(op);
putSNum(p1);
putSNum(p2);
}
void putUOp(byte op, nat p1, nat p2) {
putByte(op);
putUNum(p1);
putUNum(p2);
}
// Encode the 'advance_loc' op-code.
void putAdvance(nat bytes) {
if (bytes <= 0x3F) {
putByte(DW_CFA_advance_loc + bytes);
} else if (bytes <= 0xFF) {
putByte(DW_CFA_advance_loc1);
putByte(bytes);
} else if (bytes <= 0xFFFF) {
putByte(DW_CFA_advance_loc2);
putByte(bytes & 0xFF);
putByte(bytes >> 8);
} else {
putByte(DW_CFA_advance_loc4);
putByte(bytes & 0xFF);
putByte((bytes & 0xFF00) >> 8);
putByte((bytes & 0xFF0000) >> 16);
putByte(bytes >> 24);
}
}
};
class FDEStream : public DStream {
public:
FDEStream(FDE *to, Nat &pos) : DStream(to->data, FDE_DATA), dest(pos) {
this->pos = dest;
}
~FDEStream() {
dest = pos;
dbg_assert(!overflow(), L"Increase FDE_DATA to at least " + ::toS(roundUp(pos, nat(sizeof(void *)))) + L"!");
}
Nat &dest;
};
class FDEIStream {
public:
FDEIStream(FDE *from) : data(from->data), len(FDE_DATA), pos(from->firstFree()) {}
Byte getByte() {
if (pos < len)
return data[pos++];
else
return 0x0;
}
Nat getUNum() {
Nat out = 0;
Nat shift = 0;
while (true) {
Byte b = getByte();
if (b & 0x80) {
out |= (b & 0x7F) << shift;
shift += 7;
} else {
out |= b << shift;
shift += 7;
break;
}
}
return out;
}
Int getSNum() {
Nat out = 0;
Nat shift = 0;
while (true) {
Byte b = getByte();
if (b & 0x80) {
out |= (b & 0x7F) << shift;
shift += 7;
} else {
out |= b << shift;
shift += 7;
break;
}
}
// Check if negative:
if (out >> (shift - 1)) {
// Yes, that means we need to add sign bits:
out |= Nat(0xFFFFFFFF) << shift;
}
return Int(out);
}
Bool atEnd() const {
return pos >= len;
}
private:
Byte *data;
Nat len;
Nat pos;
};
}
}
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