LocationList location_list(
simgrid::mc::ObjectInformation& info,
Dwarf_Attribute& attr)
{
LocationList locations;
std::ptrdiff_t offset = 0;
while (1) {
Dwarf_Addr base, start, end;
Dwarf_Op *ops;
std::size_t len;
offset = dwarf_getlocations(
&attr, offset, &base, &start, &end, &ops, &len);
if (offset == 0)
break;
else if (offset == -1)
xbt_die("Error while loading location list");
std::uint64_t base_address = (std::uint64_t) info.base_address();
LocationListEntry::range_type range;
if (start == 0)
// If start == 0, this is not a location list:
range = { 0, UINT64_MAX };
else
range = { base_address + start, base_address + end };
locations.push_back({ DwarfExpression(ops, ops+len), range });
}
return locations;
}
/* Get all variables and print their value expressions. */
static void
print_varlocs (Dwarf_Die *funcdie)
{
// Display frame base for function if it exists.
// Should be used for DW_OP_fbreg.
has_frame_base = dwarf_hasattr (funcdie, DW_AT_frame_base);
if (has_frame_base)
{
Dwarf_Attribute fb_attr;
if (dwarf_attr (funcdie, DW_AT_frame_base, &fb_attr) == NULL)
error (EXIT_FAILURE, 0, "dwarf_attr fb: %s", dwarf_errmsg (-1));
Dwarf_Op *fb_expr;
size_t fb_exprlen;
if (dwarf_getlocation (&fb_attr, &fb_expr, &fb_exprlen) == 0)
{
// Covers all of function.
Dwarf_Addr entrypc;
if (dwarf_entrypc (funcdie, &entrypc) != 0)
error (EXIT_FAILURE, 0, "dwarf_entrypc: %s", dwarf_errmsg (-1));
printf (" frame_base: ");
if (entrypc == 0)
printf ("XXX zero address"); // XXX bad DWARF?
else
print_expr_block (&fb_attr, fb_expr, fb_exprlen, entrypc);
printf ("\n");
}
else
{
Dwarf_Addr base, start, end;
ptrdiff_t off = 0;
printf (" frame_base:\n");
while ((off = dwarf_getlocations (&fb_attr, off, &base,
&start, &end,
&fb_expr, &fb_exprlen)) > 0)
{
printf (" (%" PRIx64 ",%" PRIx64 ") ", start, end);
print_expr_block (&fb_attr, fb_expr, fb_exprlen, start);
printf ("\n");
}
if (off < 0)
error (EXIT_FAILURE, 0, "dwarf_getlocations fb: %s",
dwarf_errmsg (-1));
}
}
else if (dwarf_tag (funcdie) == DW_TAG_inlined_subroutine)
{
// See whether the subprogram we are inlined into has a frame
// base we should use.
Dwarf_Die *scopes;
int n = dwarf_getscopes_die (funcdie, &scopes);
if (n <= 0)
error (EXIT_FAILURE, 0, "dwarf_getscopes_die: %s", dwarf_errmsg (-1));
while (n-- > 0)
if (dwarf_tag (&scopes[n]) == DW_TAG_subprogram
&& dwarf_hasattr (&scopes[n], DW_AT_frame_base))
{
has_frame_base = true;
break;
}
free (scopes);
}
if (! dwarf_haschildren (funcdie))
return;
Dwarf_Die child;
int res = dwarf_child (funcdie, &child);
if (res < 0)
error (EXIT_FAILURE, 0, "dwarf_child: %s", dwarf_errmsg (-1));
/* We thought there was a child, but the child list was actually
empty. This isn't technically an error in the DWARF, but it is
certainly non-optimimal. */
if (res == 1)
return;
do
{
int tag = dwarf_tag (&child);
if (tag == DW_TAG_variable || tag == DW_TAG_formal_parameter)
{
const char *what = tag == DW_TAG_variable ? "variable" : "parameter";
print_die (&child, what, 2);
if (dwarf_hasattr (&child, DW_AT_location))
{
Dwarf_Attribute attr;
if (dwarf_attr (&child, DW_AT_location, &attr) == NULL)
error (EXIT_FAILURE, 0, "dwarf_attr: %s", dwarf_errmsg (-1));
Dwarf_Op *expr;
size_t exprlen;
if (dwarf_getlocation (&attr, &expr, &exprlen) == 0)
{
// Covers all ranges of the function.
// Evaluate the expression block for each range.
ptrdiff_t offset = 0;
Dwarf_Addr base, begin, end;
do
{
offset = dwarf_ranges (funcdie, offset, &base,
&begin, &end);
if (offset < 0)
error (EXIT_FAILURE, 0, "dwarf_ranges: %s",
dwarf_errmsg (-1));
if (offset > 0)
{
if (exprlen == 0)
printf (" (%"
PRIx64 ",%" PRIx64
") <empty expression>\n", begin, end);
else
print_expr_block_addrs (&attr, begin, end,
expr, exprlen);
}
}
while (offset > 0);
if (offset < 0)
error (EXIT_FAILURE, 0, "dwarf_ranges: %s",
dwarf_errmsg (-1));
}
else
{
Dwarf_Addr base, begin, end;
ptrdiff_t offset = 0;
while ((offset = dwarf_getlocations (&attr, offset,
&base, &begin, &end,
&expr, &exprlen)) > 0)
if (begin >= end)
printf (" (%" PRIx64 ",%" PRIx64
") <empty range>\n", begin, end); // XXX report?
else
{
print_expr_block_addrs (&attr, begin, end,
expr, exprlen);
// Extra sanity check for dwarf_getlocation_addr
// Must at least find one range for begin and end-1.
Dwarf_Op *expraddr;
size_t expraddr_len;
int locs = dwarf_getlocation_addr (&attr, begin,
&expraddr,
&expraddr_len, 1);
assert (locs == 1);
locs = dwarf_getlocation_addr (&attr, end - 1,
&expraddr,
&expraddr_len, 1);
assert (locs == 1);
}
if (offset < 0)
error (EXIT_FAILURE, 0, "dwarf_getlocations: %s",
dwarf_errmsg (-1));
}
}
else if (dwarf_hasattr (&child, DW_AT_const_value))
{
printf (" <constant value>\n"); // Lookup type and print.
}
else
{
printf (" <no value>\n");
}
}
}
while (dwarf_siblingof (&child, &child) == 0);
}
