#include <libdwarf.h>
#include <dwarf.h>

#include <err.h>
#include <stdio.h>

#include <fcntl.h>
#include <stdlib.h>

Dwarf_Off
GetDieOffset(Dwarf_Die die)
{
	Dwarf_Error derr;
	Dwarf_Off offset;
	int error;

	error = dwarf_dieoffset(die, &offset, &derr);
	if (error != 0)
		errx(1, "dwarf_dieoffset failed");
	return (offset);
}

static void
ProcessInlined(Dwarf_Debug dwarf, Dwarf_Die die)
{
	Dwarf_Error derr;
	Dwarf_Ranges *array;
	Dwarf_Signed i, count;
	Dwarf_Unsigned off, baseAddr, size;
	uintptr_t low, high;
	int error;

	error = dwarf_attrval_unsigned(die, DW_AT_ranges, &off, &derr);
	if (error != DW_DLV_OK)
		errx(1, "dwarf_attrval_unsigned failed");

	error = dwarf_get_ranges(dwarf, off, &array, &count, &size, &derr);
	if (error != 0)
		errx(1, "dwarf_get_ranges failed\n");

	error = dwarf_attrval_unsigned(die, DW_AT_low_pc, &baseAddr, &derr);
	if (error == 0)
		baseAddr = 0;

	for (i = 0; i < count; i++) {
		switch (array[i].dwr_type) {
		case DW_RANGES_ENTRY:
			low = baseAddr + array[i].dwr_addr1;
			high = baseAddr + array[i].dwr_addr2;
			fprintf(stderr, "Range %lx-%lx (base=%lx, addr1=%lx, addr2=%lx)\n",
				    low, high, baseAddr, array[i].dwr_addr1,
				    array[i].dwr_addr2);
			break;
		case DW_RANGES_ADDRESS_SELECTION:
			baseAddr = array[i].dwr_addr2;
			break;
		case DW_RANGES_END:
			goto done;
		}
	}

done:
	exit(0);
}

void
ProcessSubprogram(Dwarf_Debug dwarf, Dwarf_Die sub)
{
	Dwarf_Die die, next;
	Dwarf_Error derr;
	int error;

	error = dwarf_child(sub, &die, &derr);
	if (error != 0)
		errx(1, "dwarf_child failed");

	while (die != NULL) {
		if (GetDieOffset(die) == 0x21a8ab7)
			ProcessInlined(dwarf, die);
		
		error = dwarf_siblingof(dwarf, die, &next, &derr);
		if (error != 0)
			errx(1, "dwarf_siblingof failed");
		
		dwarf_dealloc(dwarf, die, DW_DLA_DIE);
		die = next;
	}
}

void
ProcessCU(Dwarf_Debug dwarf, Dwarf_Die cu)
{
	Dwarf_Die die, next;
	Dwarf_Error derr;
	int error;

	error = dwarf_child(cu, &die, &derr);
	if (error != 0)
		errx(1, "dwarf_child failed");

	while (die != NULL) {
		if (GetDieOffset(die) == 0x21a8a7d)
			ProcessSubprogram(dwarf, die);
		
		error = dwarf_siblingof(dwarf, die, &next, &derr);
		if (error != 0)
			errx(1, "dwarf_siblingof failed");
		
		dwarf_dealloc(dwarf, die, DW_DLA_DIE);
		die = next;
	}
}

int main(int argc, char **argv)
{
	Dwarf_Debug dwarf;
	Dwarf_Die cu;
	Dwarf_Error derr;
	Dwarf_Unsigned next_offset;
	int error;
	
	if (argc != 2)
		errx(1, "Usage: %s <input file>", argv[0]);

	int fd = open(argv[1], O_RDONLY);
	if (fd < 0)
		err(1, "open failed");
	
	error = dwarf_init(fd, DW_DLC_READ, NULL, NULL, &dwarf, &derr);
	if (error != 0)
		errx(1, "dwarf_init failed");

	while (1) {
		error = dwarf_next_cu_header(dwarf, NULL, NULL, NULL, NULL,
		    &next_offset, &derr);
		if (error != DW_DLV_OK) {
			fprintf(stderr, "dwarf_next_cu_header: Got error %d\n", error);
			break;
		}

		error = dwarf_siblingof(dwarf, NULL, &cu, &derr);
		if (error != DW_DLV_OK) {
			fprintf(stderr, "dwarf_siblingof: Got error %d\n", error);
			break;
		}
		
		Dwarf_Off off = GetDieOffset(cu);
		if (off == 0x21a2334)
			ProcessCU(dwarf, cu);
	}
	
	return 0;
}