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loc2c.c
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#include <config.h>
#include <inttypes.h>
#include <stdbool.h>
#include <obstack.h>
#include <stdio.h>
#include <stdlib.h>
#include <error.h>
#include <dwarf.h>
#include <elfutils/libdw.h>
#include <assert.h>
#include "loc2c.h"
#include "config.h"
#include <elfutils/libdw.h>
#ifdef HAVE_ELFUTILS_VERSION_H
#include <elfutils/version.h>
#endif
#if !defined(_ELFUTILS_PREREQ)
// make a dummy PREREQ check for elfutils < 0.138
#define _ELFUTILS_PREREQ(major, minor) (0 >= 1)
#endif
#if ! _ELFUTILS_PREREQ(0,142)
#define DW_TAG_rvalue_reference_type 0x42
#endif
#define N_(x) x
#define STACK_TYPE "intptr_t" /* Must be the signed type. */
#define UTYPE "uintptr_t" /* Must be the unsigned type. */
#define SFORMAT "%" PRId64 "L"
#define UFORMAT "%" PRIu64 "UL"
#define AFORMAT "%#" PRIx64 "UL"
#define STACKFMT "s%u"
struct location
{
struct location *next;
void (*fail) (void *arg, const char *fmt, ...)
__attribute__ ((noreturn, format (printf, 2, 3)));
void *fail_arg;
void (*emit_address) (void *fail_arg, struct obstack *, Dwarf_Addr);
const Dwarf_Op *ops;
size_t nops;
Dwarf_Word byte_size;
enum
{
loc_address, loc_register, loc_noncontiguous,
loc_decl, loc_fragment, loc_final
} type;
struct location *frame_base;
union
{
struct /* loc_address, loc_fragment, loc_final */
{
const char *declare; /* Temporary that needs declared. */
char *program; /* C fragment, leaves address in s0. */
unsigned int stack_depth; /* Temporaries "s0..<N>" used by it. */
bool used_deref; /* Program uses "deref" macro. */
} address;
struct /* loc_register */
{
unsigned int regno;
Dwarf_Word offset;
} reg;
struct location *pieces; /* loc_noncontiguous */
};
};
static struct location *
alloc_location (struct obstack *pool, struct location *origin)
{
struct location *loc = obstack_alloc (pool, sizeof *loc);
loc->fail = origin->fail;
loc->fail_arg = origin->fail_arg;
loc->emit_address = origin->emit_address;
loc->byte_size = 0;
loc->frame_base = NULL;
return loc;
}
#define FAIL(loc, fmt, ...) \
(*(loc)->fail) ((loc)->fail_arg, fmt, ## __VA_ARGS__)
static void
default_emit_address (void *fail_arg __attribute__ ((unused)),
struct obstack *pool, Dwarf_Addr address)
{
obstack_printf (pool, AFORMAT, address);
}
/* Synthesize a new loc_address using the program on the obstack. */
static struct location *
new_synthetic_loc (struct obstack *pool, struct location *origin, bool deref)
{
obstack_1grow (pool, '\0');
char *program = obstack_finish (pool);
struct location *loc = alloc_location (pool, origin);
loc->next = NULL;
loc->byte_size = 0;
loc->type = loc_address;
loc->address.program = program;
loc->address.stack_depth = 0;
loc->address.declare = NULL;
loc->address.used_deref = deref;
if (origin->type == loc_register)
{
loc->ops = origin->ops;
loc->nops = origin->nops;
}
else
{
loc->ops = NULL;
loc->nops = 0;
}
return loc;
}
/* Die in the middle of an expression. */
static struct location *
lose (struct location *loc,
const char *failure, const Dwarf_Op *lexpr, size_t i)
{
FAIL (loc, N_("%s in DWARF expression [%Zu] at %" PRIu64
" (%#x: %" PRId64 ", %" PRId64 ")"),
failure, i, lexpr[i].offset,
lexpr[i].atom, lexpr[i].number, lexpr[i].number2);
return NULL;
}
/* Translate a (constrained) DWARF expression into C code
emitted to the obstack POOL. INDENT is the number of indentation levels.
ADDRBIAS is the difference between runtime and Dwarf info addresses.
INPUT is null or an expression to be initially pushed on the stack.
If NEED_FB is null, fail on DW_OP_fbreg, else set *NEED_FB to true
and emit "frame_base" for it. On success, set *MAX_STACK to the number
of stack slots required. On failure, set *LOSER to the index in EXPR
of the operation we could not handle.
Returns a failure message or null for success. */
static const char *
translate (struct obstack *pool, int indent, Dwarf_Addr addrbias,
Dwarf_Attribute *attr, const Dwarf_Op *expr, const size_t len,
struct location *input,
bool *need_fb, size_t *loser,
struct location *loc)
{
loc->ops = expr;
loc->nops = len;
#define DIE(msg) return (*loser = i, N_(msg))
#define emit(fmt, ...) obstack_printf (pool, fmt, ## __VA_ARGS__)
unsigned int stack_depth = 0, max_stack = 0;
inline void deepen (void)
{
if (stack_depth == max_stack)
++max_stack;
}
#define POP(var) \
if (stack_depth > 0) \
--stack_depth; \
else if (tos_register != -1) \
fetch_tos_register (); \
else \
goto underflow; \
int var = stack_depth
#define PUSH (deepen (), stack_depth++)
#define STACK(idx) (stack_depth - 1 - (idx))
/* Don't put stack operations in the arguments to this. */
#define push(fmt, ...) \
emit ("%*s" STACKFMT " = " fmt ";\n", indent * 2, "", PUSH, ## __VA_ARGS__)
int tos_register = -1;
inline void fetch_tos_register (void)
{
deepen ();
emit ("%*s" STACKFMT " = fetch_register (%d);\n",
indent * 2, "", stack_depth, tos_register);
tos_register = -1;
}
if (input != NULL)
switch (input->type)
{
case loc_address:
push ("addr");
break;
case loc_register:
tos_register = input->reg.regno;
break;
default:
abort ();
break;
}
size_t i;
bool used_deref = false;
inline const char *finish (struct location *piece)
{
if (stack_depth > 1)
DIE ("multiple values left on stack");
if (stack_depth == 1)
{
obstack_1grow (pool, '\0');
char *program = obstack_finish (pool);
piece->type = loc_address;
piece->address.declare = NULL;
piece->address.program = program;
piece->address.stack_depth = max_stack;
piece->address.used_deref = used_deref;
used_deref = false;
}
else if (tos_register == -1)
DIE ("stack underflow");
else if (obstack_object_size (pool) != 0)
DIE ("register value must stand alone in location expression");
else
{
piece->type = loc_register;
piece->reg.regno = tos_register;
piece->reg.offset = 0;
}
return NULL;
}
struct location *pieces = NULL, **tailpiece = &pieces;
size_t piece_expr_start = 0;
Dwarf_Word piece_total_bytes = 0;
for (i = 0; i < len; ++i)
{
unsigned int reg;
uint_fast8_t sp;
Dwarf_Word value;
switch (expr[i].atom)
{
/* Basic stack operations. */
case DW_OP_nop:
break;
case DW_OP_dup:
if (stack_depth < 1)
goto underflow;
else
{
unsigned int tos = STACK (0);
push (STACKFMT, tos);
}
break;
case DW_OP_drop:
{
POP (ignore);
emit ("%*s/* drop " STACKFMT "*/\n", indent * 2, "", ignore);
break;
}
case DW_OP_pick:
sp = expr[i].number;
op_pick:
if (sp >= stack_depth)
goto underflow;
sp = STACK (sp);
push (STACKFMT, sp);
break;
case DW_OP_over:
sp = 1;
goto op_pick;
case DW_OP_swap:
if (stack_depth < 2)
goto underflow;
deepen (); /* Use a temporary slot. */
emit ("%*s"
STACKFMT " = " STACKFMT ", "
STACKFMT " = " STACKFMT ", "
STACKFMT " = " STACKFMT ";\n",
indent * 2, "",
STACK (-1), STACK (0),
STACK (0), STACK (1),
STACK (1), STACK (-1));
break;
case DW_OP_rot:
if (stack_depth < 3)
goto underflow;
deepen (); /* Use a temporary slot. */
emit ("%*s"
STACKFMT " = " STACKFMT ", "
STACKFMT " = " STACKFMT ", "
STACKFMT " = " STACKFMT ", "
STACKFMT " = " STACKFMT ";\n",
indent * 2, "",
STACK (-1), STACK (0),
STACK (0), STACK (1),
STACK (1), STACK (2),
STACK (3), STACK (-1));
break;
/* Control flow operations. */
case DW_OP_skip:
{
Dwarf_Off target = expr[i].offset + 3 + expr[i].number;
while (i + 1 < len && expr[i + 1].offset < target)
++i;
if (expr[i + 1].offset != target)
DIE ("invalid skip target");
break;
}
case DW_OP_bra:
DIE ("conditional branches not supported");
break;
/* Memory access. */
case DW_OP_deref:
{
POP (addr);
push ("deref (sizeof (void *), " STACKFMT ")", addr);
used_deref = true;
}
break;
case DW_OP_deref_size:
{
POP (addr);
push ("deref (" UFORMAT ", " STACKFMT ")",
expr[i].number, addr);
used_deref = true;
}
break;
case DW_OP_xderef:
{
POP (addr);
POP (as);
push ("xderef (sizeof (void *), " STACKFMT ", " STACKFMT ")",
addr, as);
used_deref = true;
}
break;
case DW_OP_xderef_size:
{
POP (addr);
POP (as);
push ("xderef (" UFORMAT ", " STACKFMT ", " STACKFMT ")",
expr[i].number, addr, as);
used_deref = true;
}
break;
/* Constant-value operations. */
case DW_OP_addr:
emit ("%*s" STACKFMT " = ", indent * 2, "", PUSH);
(*loc->emit_address) (loc->fail_arg, pool,
addrbias + expr[i].number);
emit (";\n");
break;
case DW_OP_lit0 ... DW_OP_lit31:
value = expr[i].atom - DW_OP_lit0;
goto op_const;
case DW_OP_const1u:
case DW_OP_const1s:
case DW_OP_const2u:
case DW_OP_const2s:
case DW_OP_const4u:
case DW_OP_const4s:
case DW_OP_const8u:
case DW_OP_const8s:
case DW_OP_constu:
case DW_OP_consts:
value = expr[i].number;
op_const:
push (SFORMAT, value);
break;
/* Arithmetic operations. */
#define UNOP(dw_op, c_op) \
case DW_OP_##dw_op: \
{ \
POP (tos); \
push ("%s (" STACKFMT ")", #c_op, tos); \
} \
break
#define BINOP(dw_op, c_op) \
case DW_OP_##dw_op: \
{ \
POP (b); \
POP (a); \
push (STACKFMT " %s " STACKFMT, a, #c_op, b); \
} \
break
UNOP (abs, op_abs);
BINOP (and, &);
BINOP (div, /);
BINOP (minus, -);
BINOP (mod, %);
BINOP (mul, *);
UNOP (neg, -);
UNOP (not, ~);
BINOP (or, |);
BINOP (plus, +);
BINOP (shl, <<);
BINOP (shra, >>);
BINOP (xor, ^);
/* Comparisons are binary operators too. */
BINOP (le, <=);
BINOP (ge, >=);
BINOP (eq, ==);
BINOP (lt, <);
BINOP (gt, >);
BINOP (ne, !=);
#undef UNOP
#undef BINOP
case DW_OP_shr:
{
POP (b);
POP (a);
push ("(%s) " STACKFMT " >> (%s)" STACKFMT,
UTYPE, a, UTYPE, b);
break;
}
case DW_OP_plus_uconst:
{
POP (x);
push (STACKFMT " + " UFORMAT, x, expr[i].number);
}
break;
/* Register-relative addressing. */
case DW_OP_breg0 ... DW_OP_breg31:
reg = expr[i].atom - DW_OP_breg0;
value = expr[i].number;
goto op_breg;
case DW_OP_bregx:
reg = expr[i].number;
value = expr[i].number2;
op_breg:
push ("fetch_register (%u) + " SFORMAT, reg, value);
break;
case DW_OP_fbreg:
if (need_fb == NULL)
DIE ("DW_OP_fbreg from DW_AT_frame_base");
*need_fb = true;
push ("frame_base + " SFORMAT, expr[i].number);
break;
/* Direct register contents. */
case DW_OP_reg0 ... DW_OP_reg31:
reg = expr[i].atom - DW_OP_reg0;
goto op_reg;
case DW_OP_regx:
reg = expr[i].number;
op_reg:
tos_register = reg;
break;
/* Special magic. */
case DW_OP_piece:
if (stack_depth > 1)
/* If this ever happens we could copy the program. */
DIE ("DW_OP_piece left multiple values on stack");
else
{
/* The obstack has a pending program for loc_address,
so we must finish that piece off before we can
allocate again. */
struct location temp_piece =
{
.fail = loc->fail,
.fail_arg = loc->fail_arg,
.emit_address = loc->emit_address,
.frame_base = NULL,
.ops = &expr[piece_expr_start],
.nops = i - piece_expr_start,
};
const char *failure = finish (&temp_piece);
if (failure != NULL)
return failure;
struct location *piece = obstack_alloc (pool, sizeof *piece);
*piece = temp_piece;
piece_expr_start = i + 1;
piece_total_bytes += piece->byte_size = expr[i].number;
*tailpiece = piece;
tailpiece = &piece->next;
piece->next = NULL;
}
break;
case DW_OP_stack_value:
DIE ("DW_OP_stack_value not supported");
break;
case DW_OP_implicit_value:
{
if (attr == NULL)
DIE ("DW_OP_implicit_value used in invalid context (no dwarf attribute, ABI return value location?)");
else
{
#if ! _ELFUTILS_PREREQ(0,143)
Dwarf_Block block;
Dwarf_Op *op = (Dwarf_Op *) &expr[i];
if (dwarf_getlocation_implicit_value (attr, op, &block) != 0)
DIE("DW_OP_implicit_value, dwarf_getlocation_implicit_value failed");
else
#endif
DIE ("DW_OP_implicit_value not supported");
}
break;
}
case DW_OP_call_frame_cfa:
// We pick this out when processing DW_AT_frame_base in
// so it really shouldn't turn up here.
if (need_fb == NULL)
DIE ("DW_OP_call_frame_cfa while processing frame base");
else
DIE ("DW_OP_call_frame_cfa not expected outside DW_AT_frame_base");
break;
case DW_OP_push_object_address:
DIE ("XXX DW_OP_push_object_address");
break;
default:
DIE ("unrecognized operation");
break;
}
}
if (pieces == NULL)
return finish (loc);
if (piece_expr_start != i)
DIE ("extra operations after last DW_OP_piece");
loc->type = loc_noncontiguous;
loc->pieces = pieces;
loc->byte_size = piece_total_bytes;
return NULL;
underflow:
DIE ("stack underflow");
#undef emit
#undef push
#undef PUSH
#undef POP
#undef STACK
#undef DIE
}
/* Translate a location starting from an address or nothing. */
static struct location *
location_from_address (struct obstack *pool,
void (*fail) (void *arg, const char *fmt, ...)
__attribute__ ((noreturn, format (printf, 2, 3))),
void *fail_arg,
void (*emit_address) (void *fail_arg,
struct obstack *, Dwarf_Addr),
int indent, Dwarf_Addr dwbias,
Dwarf_Attribute *attr,
const Dwarf_Op *expr, size_t len, Dwarf_Addr address,
struct location **input, Dwarf_Attribute *fb_attr,
const Dwarf_Op *cfa_ops)
{
struct location *loc = obstack_alloc (pool, sizeof *loc);
loc->fail = *input == NULL ? fail : (*input)->fail;
loc->fail_arg = *input == NULL ? fail_arg : (*input)->fail_arg;
loc->emit_address = *input == NULL ? emit_address : (*input)->emit_address;
loc->byte_size = 0;
loc->frame_base = NULL;
bool need_fb = false;
size_t loser;
const char *failure = translate (pool, indent + 1, dwbias, attr, expr, len,
*input, &need_fb, &loser, loc);
if (failure != NULL)
return lose (loc, failure, expr, loser);
loc->next = NULL;
if (need_fb)
{
/* The main expression uses DW_OP_fbreg, so we need to compute
the DW_AT_frame_base attribute expression's value first. */
if (fb_attr == NULL)
FAIL (loc, N_("required DW_AT_frame_base attribute not supplied"));
Dwarf_Op *fb_expr;
size_t fb_len;
switch (dwarf_getlocation_addr (fb_attr, address - dwbias,
&fb_expr, &fb_len, 1))
{
case 1: /* Should always happen. */
if (fb_len == 0)
goto fb_inaccessible;
break;
default: /* Shouldn't happen. */
case -1:
FAIL (loc, N_("dwarf_getlocation_addr (form %#x): %s"),
dwarf_whatform (fb_attr), dwarf_errmsg (-1));
return NULL;
case 0: /* Shouldn't happen. */
fb_inaccessible:
FAIL (loc, N_("DW_AT_frame_base not accessible at this address"));
return NULL;
}
// If it is DW_OP_call_frame_cfa then get cfi cfa ops.
const Dwarf_Op * fb_ops;
if (fb_len == 1 && fb_expr[0].atom == DW_OP_call_frame_cfa)
{
if (cfa_ops == NULL)
FAIL (loc, N_("No cfa_ops supplied, but needed by DW_OP_call_frame_cfa"));
fb_ops = cfa_ops;
}
else
fb_ops = fb_expr;
loc->frame_base = alloc_location (pool, loc);
failure = translate (pool, indent + 1, dwbias, attr, fb_ops, fb_len, NULL,
NULL, &loser, loc->frame_base);
if (failure != NULL)
return lose (loc, failure, fb_expr, loser);
}
if (*input != NULL)
(*input)->next = loc;
*input = loc;
return loc;
}
/* Translate a location starting from a non-address "on the top of the
stack". The *INPUT location is a register name or noncontiguous
object specification, and this expression wants to find the "address"
of an object (or the actual value) relative to that "address". */
static struct location *
location_relative (struct obstack *pool,
int indent, Dwarf_Addr dwbias, Dwarf_Attribute *attr,
const Dwarf_Op *expr, size_t len, Dwarf_Addr address,
struct location **input, Dwarf_Attribute *fb_attr,
const Dwarf_Op *cfa_ops)
{
Dwarf_Sword *stack = NULL;
unsigned int stack_depth = 0, max_stack = 0;
inline void deepen (void)
{
if (stack_depth == max_stack)
{
++max_stack;
obstack_blank (pool, sizeof stack[0]);
stack = (void *) obstack_base (pool);
}
}
#define POP(var) \
if (stack_depth > 0) \
--stack_depth; \
else \
goto underflow; \
int var = stack_depth
#define PUSH (deepen (), stack_depth++)
#define STACK(idx) (stack_depth - 1 - (idx))
#define STACKWORD(idx) stack[STACK (idx)]
/* Don't put stack operations in the arguments to this. */
#define push(value) (stack[PUSH] = (value))
const char *failure = NULL;
#define DIE(msg) do { failure = N_(msg); goto fail; } while (0)
struct location *head = NULL;
size_t i;
for (i = 0; i < len; ++i)
{
uint_fast8_t sp;
Dwarf_Word value;
switch (expr[i].atom)
{
/* Basic stack operations. */
case DW_OP_nop:
break;
case DW_OP_dup:
if (stack_depth < 1)
goto underflow;
else
{
unsigned int tos = STACK (0);
push (stack[tos]);
}
break;
case DW_OP_drop:
if (stack_depth > 0)
--stack_depth;
else if (*input != NULL)
/* Mark that we have consumed the input. */
*input = NULL;
else
/* Hits if cleared above, or if we had no input at all. */
goto underflow;
break;
case DW_OP_pick:
sp = expr[i].number;
op_pick:
if (sp >= stack_depth)
goto underflow;
sp = STACK (sp);
push (stack[sp]);
break;
case DW_OP_over:
sp = 1;
goto op_pick;
case DW_OP_swap:
if (stack_depth < 2)
goto underflow;
deepen (); /* Use a temporary slot. */
STACKWORD (-1) = STACKWORD (0);
STACKWORD (0) = STACKWORD (1);
STACKWORD (1) = STACKWORD (-1);
break;
case DW_OP_rot:
if (stack_depth < 3)
goto underflow;
deepen (); /* Use a temporary slot. */
STACKWORD (-1) = STACKWORD (0);
STACKWORD (0) = STACKWORD (1);
STACKWORD (2) = STACKWORD (2);
STACKWORD (2) = STACKWORD (-1);
break;
/* Control flow operations. */
case DW_OP_bra:
{
POP (taken);
if (stack[taken] == 0)
break;
}
/*FALLTHROUGH*/
case DW_OP_skip:
{
Dwarf_Off target = expr[i].offset + 3 + expr[i].number;
while (i + 1 < len && expr[i + 1].offset < target)
++i;
if (expr[i + 1].offset != target)
DIE ("invalid skip target");
break;
}
/* Memory access. */
case DW_OP_deref:
case DW_OP_deref_size:
case DW_OP_xderef:
case DW_OP_xderef_size:
/* Register-relative addressing. */
case DW_OP_breg0 ... DW_OP_breg31:
case DW_OP_bregx:
case DW_OP_fbreg:
/* This started from a register, but now it's following a pointer.
So we can do the translation starting from address here. */
return location_from_address (pool, NULL, NULL, NULL, indent, dwbias,
attr, expr, len, address, input, fb_attr,
cfa_ops);
/* Constant-value operations. */
case DW_OP_addr:
DIE ("static calculation depends on load-time address");
push (dwbias + expr[i].number);
break;
case DW_OP_lit0 ... DW_OP_lit31:
value = expr[i].atom - DW_OP_lit0;
goto op_const;
case DW_OP_const1u:
case DW_OP_const1s:
case DW_OP_const2u:
case DW_OP_const2s:
case DW_OP_const4u:
case DW_OP_const4s:
case DW_OP_const8u:
case DW_OP_const8s:
case DW_OP_constu:
case DW_OP_consts:
value = expr[i].number;
op_const:
push (value);
break;
/* Arithmetic operations. */
#define UNOP(dw_op, c_op) \
case DW_OP_##dw_op: \
{ \
POP (tos); \
push (c_op (stack[tos])); \
} \
break
#define BINOP(dw_op, c_op) \
case DW_OP_##dw_op: \
{ \
POP (b); \
POP (a); \
push (stack[a] c_op stack[b]); \
} \
break
#define op_abs(x) (x < 0 ? -x : x)
UNOP (abs, op_abs);
BINOP (and, &);
BINOP (div, /);
BINOP (mod, %);
BINOP (mul, *);
UNOP (neg, -);
UNOP (not, ~);
BINOP (or, |);
BINOP (shl, <<);
BINOP (shra, >>);
BINOP (xor, ^);
/* Comparisons are binary operators too. */
BINOP (le, <=);
BINOP (ge, >=);
BINOP (eq, ==);
BINOP (lt, <);
BINOP (gt, >);
BINOP (ne, !=);
#undef UNOP
#undef BINOP
case DW_OP_shr:
{
POP (b);
POP (a);
push ((Dwarf_Word) stack[a] >> (Dwarf_Word) stack[b]);
break;
}
/* Simple addition we may be able to handle relative to
the starting register name. */
case DW_OP_minus:
{
POP (tos);
value = -stack[tos];
goto plus;
}
case DW_OP_plus:
{
POP (tos);
value = stack[tos];
goto plus;
}
case DW_OP_plus_uconst:
value = expr[i].number;
plus:
if (stack_depth > 0)
{
/* It's just private diddling after all. */
POP (a);
push (stack[a] + value);
break;
}
if (*input == NULL)
goto underflow;
/* This is the primary real-world case: the expression takes
the input address and adds a constant offset. */
while ((*input)->type == loc_noncontiguous)
{
/* We are starting from a noncontiguous object (DW_OP_piece).
Find the piece we want. */
struct location *piece = (*input)->pieces;
while (piece != NULL && value >= piece->byte_size)
{
value -= piece->byte_size;
piece = piece->next;
}
if (piece == NULL)
DIE ("offset outside available pieces");
*input = piece;
}
switch ((*input)->type)
{
case loc_address:
{
/* The piece we want is actually in memory. Use the same
program to compute the address from the preceding input. */
struct location *loc = alloc_location (pool, *input);
*loc = **input;
if (head == NULL)
head = loc;
(*input)->next = loc;
if (value == 0)
{
/* The piece addresses exactly where we want to go. */
loc->next = NULL;
*input = loc;
}
else
{
/* Add a second fragment to offset the piece address. */
obstack_printf (pool, "%*saddr += " SFORMAT "\n",
indent * 2, "", value);
*input = loc->next = new_synthetic_loc (pool, *input,
false);
}
if (i + 1 < len)
{
/* This expression keeps going, but further
computations now have an address to start with.
So we can punt to the address computation generator. */
loc = location_from_address (pool, NULL, NULL, NULL,
indent, dwbias, attr,
&expr[i + 1], len - i - 1,
address, input, fb_attr,
cfa_ops);
if (loc == NULL)
return NULL;
}
/* That's all she wrote. */
return head;
}
case loc_register:
/* This piece (or the whole struct) fits in a register. */
(*input)->reg.offset += value;
return head ?: *input;
default:
abort ();
}
break;
/* Direct register contents. */
case DW_OP_reg0 ... DW_OP_reg31:
case DW_OP_regx:
DIE ("register");
break;