/* Frame unwinder for frames with DWARF Call Frame Information.
- Copyright 2003 Free Software Foundation, Inc.
+ Copyright 2003, 2004 Free Software Foundation, Inc.
Contributed by Mark Kettenis.
/* Structure describing a frame state. */
-enum dwarf2_reg_rule
-{
- /* Make certain that 0 maps onto the correct enum value; the
- corresponding structure is being initialized using memset zero.
- This indicates that CFI didn't provide any information at all
- about a register, leaving how to obtain its value totally
- unspecified. */
- REG_UNSPECIFIED = 0,
- /* The term "undefined" comes from the DWARF2 CFI spec which this
- code is moddeling; it indicates that the register's value is
- "undefined". GCC uses the less formal term "unsaved". Its
- definition is a combination of REG_UNDEFINED and REG_UNSPECIFIED.
- The failure to differentiate the two helps explain a few problems
- with the CFI generated by GCC. */
- REG_UNDEFINED,
- REG_SAVED_OFFSET,
- REG_SAVED_REG,
- REG_SAVED_EXP,
- REG_SAME_VALUE
-};
-
struct dwarf2_frame_state
{
/* Each register save state can be described in terms of a CFA slot,
another register, or a location expression. */
struct dwarf2_frame_state_reg_info
{
- struct dwarf2_frame_state_reg
- {
- union {
- LONGEST offset;
- ULONGEST reg;
- unsigned char *exp;
- } loc;
- ULONGEST exp_len;
- enum dwarf2_reg_rule how;
- } *reg;
+ struct dwarf2_frame_state_reg *reg;
int num_regs;
/* Used to implement DW_CFA_remember_state. */
read_reg (void *baton, int reg)
{
struct frame_info *next_frame = (struct frame_info *) baton;
+ struct gdbarch *gdbarch = get_frame_arch (next_frame);
int regnum;
char *buf;
regnum = DWARF2_REG_TO_REGNUM (reg);
- buf = (char *) alloca (register_size (current_gdbarch, regnum));
+ buf = (char *) alloca (register_size (gdbarch, regnum));
frame_unwind_register (next_frame, regnum, buf);
return extract_typed_address (buf, builtin_type_void_data_ptr);
}
insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
offset = utmp * fs->data_align;
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
- fs->regs.reg[reg].how = REG_SAVED_OFFSET;
+ fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
fs->regs.reg[reg].loc.offset = offset;
}
else if ((insn & 0xc0) == DW_CFA_restore)
insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
offset = utmp * fs->data_align;
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
- fs->regs.reg[reg].how = REG_SAVED_OFFSET;
+ fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
fs->regs.reg[reg].loc.offset = offset;
break;
case DW_CFA_undefined:
insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
- fs->regs.reg[reg].how = REG_UNDEFINED;
+ fs->regs.reg[reg].how = DWARF2_FRAME_REG_UNDEFINED;
break;
case DW_CFA_same_value:
insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
- fs->regs.reg[reg].how = REG_SAME_VALUE;
+ fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAME_VALUE;
break;
case DW_CFA_register:
insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
- fs->regs.reg[reg].how = REG_SAVED_REG;
+ fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_REG;
fs->regs.reg[reg].loc.reg = utmp;
break;
{
struct dwarf2_frame_state_reg_info *old_rs = fs->regs.prev;
- gdb_assert (old_rs);
-
- xfree (fs->regs.reg);
- fs->regs = *old_rs;
- xfree (old_rs);
+ if (old_rs == NULL)
+ {
+ complaint (&symfile_complaints, "\
+bad CFI data; mismatched DW_CFA_restore_state at 0x%s", paddr (fs->pc));
+ }
+ else
+ {
+ xfree (fs->regs.reg);
+ fs->regs = *old_rs;
+ xfree (old_rs);
+ }
}
break;
/* cfa_how deliberately not set. */
break;
+ case DW_CFA_nop:
+ break;
+
case DW_CFA_def_cfa_expression:
insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_exp_len);
fs->cfa_exp = insn_ptr;
insn_ptr = read_uleb128 (insn_ptr, insn_end, &utmp);
fs->regs.reg[reg].loc.exp = insn_ptr;
fs->regs.reg[reg].exp_len = utmp;
- fs->regs.reg[reg].how = REG_SAVED_EXP;
+ fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_EXP;
insn_ptr += utmp;
break;
- case DW_CFA_nop:
+ case DW_CFA_offset_extended_sf:
+ insn_ptr = read_uleb128 (insn_ptr, insn_end, ®);
+ insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
+ offset += fs->data_align;
+ dwarf2_frame_state_alloc_regs (&fs->regs, reg + 1);
+ fs->regs.reg[reg].how = DWARF2_FRAME_REG_SAVED_OFFSET;
+ fs->regs.reg[reg].loc.offset = offset;
+ break;
+
+ case DW_CFA_def_cfa_sf:
+ insn_ptr = read_uleb128 (insn_ptr, insn_end, &fs->cfa_reg);
+ insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
+ fs->cfa_offset = offset * fs->data_align;
+ fs->cfa_how = CFA_REG_OFFSET;
+ break;
+
+ case DW_CFA_def_cfa_offset_sf:
+ insn_ptr = read_sleb128 (insn_ptr, insn_end, &offset);
+ fs->cfa_offset = offset * fs->data_align;
+ /* cfa_how deliberately not set. */
break;
case DW_CFA_GNU_args_size:
dwarf2_frame_state_free_regs (fs->regs.prev);
fs->regs.prev = NULL;
}
+\f
+
+/* Architecture-specific operations. */
+
+/* Per-architecture data key. */
+static struct gdbarch_data *dwarf2_frame_data;
+
+struct dwarf2_frame_ops
+{
+ /* Pre-initialize the register state REG for register REGNUM. */
+ void (*init_reg) (struct gdbarch *, int, struct dwarf2_frame_state_reg *);
+};
+
+/* Default architecture-specific register state initialization
+ function. */
+
+static void
+dwarf2_frame_default_init_reg (struct gdbarch *gdbarch, int regnum,
+ struct dwarf2_frame_state_reg *reg)
+{
+ /* If we have a register that acts as a program counter, mark it as
+ a destination for the return address. If we have a register that
+ serves as the stack pointer, arrange for it to be filled with the
+ call frame address (CFA). The other registers are marked as
+ unspecified.
+
+ We copy the return address to the program counter, since many
+ parts in GDB assume that it is possible to get the return address
+ by unwinding the program counter register. However, on ISA's
+ with a dedicated return address register, the CFI usually only
+ contains information to unwind that return address register.
+
+ The reason we're treating the stack pointer special here is
+ because in many cases GCC doesn't emit CFI for the stack pointer
+ and implicitly assumes that it is equal to the CFA. This makes
+ some sense since the DWARF specification (version 3, draft 8,
+ p. 102) says that:
+
+ "Typically, the CFA is defined to be the value of the stack
+ pointer at the call site in the previous frame (which may be
+ different from its value on entry to the current frame)."
+
+ However, this isn't true for all platforms supported by GCC
+ (e.g. IBM S/390 and zSeries). Those architectures should provide
+ their own architecture-specific initialization function. */
+
+ if (regnum == PC_REGNUM)
+ reg->how = DWARF2_FRAME_REG_RA;
+ else if (regnum == SP_REGNUM)
+ reg->how = DWARF2_FRAME_REG_CFA;
+}
+
+/* Return a default for the architecture-specific operations. */
+
+static void *
+dwarf2_frame_init (struct obstack *obstack)
+{
+ struct dwarf2_frame_ops *ops;
+
+ ops = OBSTACK_ZALLOC (obstack, struct dwarf2_frame_ops);
+ ops->init_reg = dwarf2_frame_default_init_reg;
+ return ops;
+}
+
+/* Set the architecture-specific register state initialization
+ function for GDBARCH to INIT_REG. */
+
+void
+dwarf2_frame_set_init_reg (struct gdbarch *gdbarch,
+ void (*init_reg) (struct gdbarch *, int,
+ struct dwarf2_frame_state_reg *))
+{
+ struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
+
+ ops->init_reg = init_reg;
+}
+
+/* Pre-initialize the register state REG for register REGNUM. */
+
+static void
+dwarf2_frame_init_reg (struct gdbarch *gdbarch, int regnum,
+ struct dwarf2_frame_state_reg *reg)
+{
+ struct dwarf2_frame_ops *ops = gdbarch_data (gdbarch, dwarf2_frame_data);
+
+ ops->init_reg (gdbarch, regnum, reg);
+}
+\f
struct dwarf2_frame_cache
{
dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache)
{
struct cleanup *old_chain;
+ struct gdbarch *gdbarch = get_frame_arch (next_frame);
const int num_regs = NUM_REGS + NUM_PSEUDO_REGS;
struct dwarf2_frame_cache *cache;
struct dwarf2_frame_state *fs;
internal_error (__FILE__, __LINE__, "Unknown CFA rule.");
}
- /* Initialize things so that all registers are marked as
- unspecified. */
+ /* Initialize the register state. */
{
int regnum;
for (regnum = 0; regnum < num_regs; regnum++)
- cache->reg[regnum].how = REG_UNSPECIFIED;
+ dwarf2_frame_init_reg (gdbarch, regnum, &cache->reg[regnum]);
}
/* Go through the DWARF2 CFI generated table and save its register
problems when a debug info register falls outside of the
table. We need a way of iterating through all the valid
DWARF2 register numbers. */
- if (fs->regs.reg[column].how == REG_UNSPECIFIED)
+ if (fs->regs.reg[column].how == DWARF2_FRAME_REG_UNSPECIFIED)
complaint (&symfile_complaints,
"Incomplete CFI data; unspecified registers at 0x%s",
paddr (fs->pc));
-
- cache->reg[regnum] = fs->regs.reg[column];
+ else
+ cache->reg[regnum] = fs->regs.reg[column];
}
}
- /* Store the location of the return addess. If the return address
- column (adjusted) is not the same as GDB's PC_REGNUM, then this
- implies a copy from the return address column register. */
- if (fs->retaddr_column < fs->regs.num_regs
- && fs->regs.reg[fs->retaddr_column].how != REG_UNDEFINED)
- {
- /* See comment above about a possibly negative PC_REGNUM. If
- this assertion fails, it's a problem with this code and not
- the architecture. */
- gdb_assert (PC_REGNUM >= 0);
- cache->reg[PC_REGNUM] = fs->regs.reg[fs->retaddr_column];
- }
- else
- {
- if (DWARF2_REG_TO_REGNUM (fs->retaddr_column) != PC_REGNUM)
- {
- /* See comment above about PC_REGNUM being negative. If
- this assertion fails, it's a problem with this code and
- not the architecture. */
- gdb_assert (PC_REGNUM >= 0);
- cache->reg[PC_REGNUM].loc.reg = fs->retaddr_column;
- cache->reg[PC_REGNUM].how = REG_SAVED_REG;
- }
- }
+ /* Eliminate any DWARF2_FRAME_REG_RA rules. */
+ {
+ int regnum;
+
+ for (regnum = 0; regnum < num_regs; regnum++)
+ {
+ if (cache->reg[regnum].how == DWARF2_FRAME_REG_RA)
+ {
+ struct dwarf2_frame_state_reg *retaddr_reg =
+ &fs->regs.reg[fs->retaddr_column];
+
+ /* It seems rather bizarre to specify an "empty" column as
+ the return adress column. However, this is exactly
+ what GCC does on some targets. It turns out that GCC
+ assumes that the return address can be found in the
+ register corresponding to the return address column.
+ Incidentally, that's how should treat a return address
+ column specifying "same value" too. */
+ if (fs->retaddr_column < fs->regs.num_regs
+ && retaddr_reg->how != DWARF2_FRAME_REG_UNSPECIFIED
+ && retaddr_reg->how != DWARF2_FRAME_REG_SAME_VALUE)
+ cache->reg[regnum] = *retaddr_reg;
+ else
+ {
+ cache->reg[regnum].loc.reg = fs->retaddr_column;
+ cache->reg[regnum].how = DWARF2_FRAME_REG_SAVED_REG;
+ }
+ }
+ }
+ }
do_cleanups (old_chain);
enum lval_type *lvalp, CORE_ADDR *addrp,
int *realnump, void *valuep)
{
+ struct gdbarch *gdbarch = get_frame_arch (next_frame);
struct dwarf2_frame_cache *cache =
dwarf2_frame_cache (next_frame, this_cache);
switch (cache->reg[regnum].how)
{
- case REG_UNDEFINED:
+ case DWARF2_FRAME_REG_UNDEFINED:
/* If CFI explicitly specified that the value isn't defined,
mark it as optimized away; the value isn't available. */
*optimizedp = 1;
*lvalp = not_lval;
*addrp = 0;
*realnump = -1;
- if (regnum == SP_REGNUM)
- {
- /* GCC defines the CFA as the value of the stack pointer
- just before the call instruction is executed. Do other
- compilers use the same definition? */
- /* DWARF V3 Draft 7 p102: Typically, the CFA is defined to
- be the value of the stack pointer at the call site in the
- previous frame (which may be different from its value on
- entry to the current frame). */
- /* DWARF V3 Draft 7 p103: The first column of the rules
- defines the rule which computes the CFA value; it may be
- either a register and a signed offset that are added
- together or a DWARF expression that is evaluated. */
- /* FIXME: cagney/2003-07-07: I don't understand this. The
- CFI info should have provided unwind information for the
- SP register and then pointed ->cfa_reg at it, not the
- reverse. Assuming that SP_REGNUM isn't negative, there
- is a very real posibility that CFA is an offset from some
- other register, having nothing to do with the unwound SP
- value. */
- /* FIXME: cagney/2003-09-05: I think I understand. GDB was
- lumping the two states "unspecified" and "undefined"
- together. Here SP_REGNUM was "unspecified", GCC assuming
- that in such a case CFA would be used. This branch of
- the if statement should be deleted - the problem of
- SP_REGNUM is now handed by the case REG_UNSPECIFIED
- below. */
- *optimizedp = 0;
- if (valuep)
- {
- /* Store the value. */
- store_typed_address (valuep, builtin_type_void_data_ptr,
- cache->cfa);
- }
- }
- else if (valuep)
+ if (valuep)
{
/* In some cases, for example %eflags on the i386, we have
to provide a sane value, even though this register wasn't
}
break;
- case REG_SAVED_OFFSET:
+ case DWARF2_FRAME_REG_SAVED_OFFSET:
*optimizedp = 0;
*lvalp = lval_memory;
*addrp = cache->cfa + cache->reg[regnum].loc.offset;
if (valuep)
{
/* Read the value in from memory. */
- read_memory (*addrp, valuep,
- register_size (current_gdbarch, regnum));
+ read_memory (*addrp, valuep, register_size (gdbarch, regnum));
}
break;
- case REG_SAVED_REG:
+ case DWARF2_FRAME_REG_SAVED_REG:
regnum = DWARF2_REG_TO_REGNUM (cache->reg[regnum].loc.reg);
frame_register_unwind (next_frame, regnum,
optimizedp, lvalp, addrp, realnump, valuep);
break;
- case REG_SAVED_EXP:
+ case DWARF2_FRAME_REG_SAVED_EXP:
*optimizedp = 0;
*lvalp = lval_memory;
*addrp = execute_stack_op (cache->reg[regnum].loc.exp,
if (valuep)
{
/* Read the value in from memory. */
- read_memory (*addrp, valuep,
- register_size (current_gdbarch, regnum));
+ read_memory (*addrp, valuep, register_size (gdbarch, regnum));
}
break;
- case REG_UNSPECIFIED:
+ case DWARF2_FRAME_REG_UNSPECIFIED:
/* GCC, in its infinite wisdom decided to not provide unwind
information for registers that are "same value". Since
DWARF2 (3 draft 7) doesn't define such behavior, said
"undefined"). Code above issues a complaint about this.
Here just fudge the books, assume GCC, and that the value is
more inner on the stack. */
- if (SP_REGNUM >= 0 && regnum == SP_REGNUM)
- {
- /* Can things get worse? Yep! One of the registers GCC
- forgot to provide unwind information for was the stack
- pointer. Outch! GCC appears to assumes that the CFA
- address can be used - after all it points to the inner
- most address of the previous frame before the function
- call and that's always the same as the stack pointer on
- return, right? Wrong. See GCC's i386 STDCALL option for
- an ABI that has a different entry and return stack
- pointer. */
- /* DWARF V3 Draft 7 p102: Typically, the CFA is defined to
- be the value of the stack pointer at the call site in the
- previous frame (which may be different from its value on
- entry to the current frame). */
- /* DWARF V3 Draft 7 p103: The first column of the rules
- defines the rule which computes the CFA value; it may be
- either a register and a signed offset that are added
- together or a DWARF expression that is evaluated. */
- /* NOTE: cagney/2003-09-05: Should issue a complaint.
- Unfortunately it turns out that DWARF2 CFI has a problem.
- Since CFI specifies the location at which a register was
- saved (not its value) it isn't possible to specify
- something like "unwound(REG) == REG + constant" using CFI
- as will almost always occure with the stack pointer. I
- guess CFI should be point SP at CFA. Ref: danielj,
- "Describing unsaved stack pointers", posted to dwarf2
- list 2003-08-15. */
- *optimizedp = 0;
- *lvalp = not_lval;
- *addrp = 0;
- *realnump = -1;
- if (valuep)
- /* Store the value. */
- store_typed_address (valuep, builtin_type_void_data_ptr,
- cache->cfa);
- }
- else
- /* Assume that the register can be found in the next inner
- most frame. */
- frame_register_unwind (next_frame, regnum,
- optimizedp, lvalp, addrp, realnump, valuep);
+ frame_register_unwind (next_frame, regnum,
+ optimizedp, lvalp, addrp, realnump, valuep);
break;
- case REG_SAME_VALUE:
+ case DWARF2_FRAME_REG_SAME_VALUE:
frame_register_unwind (next_frame, regnum,
optimizedp, lvalp, addrp, realnump, valuep);
break;
+ case DWARF2_FRAME_REG_CFA:
+ *optimizedp = 0;
+ *lvalp = not_lval;
+ *addrp = 0;
+ *realnump = -1;
+ if (valuep)
+ {
+ /* Store the value. */
+ store_typed_address (valuep, builtin_type_void_data_ptr, cache->cfa);
+ }
+ break;
+
default:
internal_error (__FILE__, __LINE__, "Unknown register rule.");
}
bfd_vma tbase;
};
-const struct objfile_data *dwarf2_frame_data;
+const struct objfile_data *dwarf2_frame_objfile_data;
static unsigned int
read_1_byte (bfd *bfd, char *buf)
case DW_EH_PE_textrel:
base = unit->tbase;
break;
+ case DW_EH_PE_funcrel:
+ /* FIXME: kettenis/20040501: For now just pretend
+ DW_EH_PE_funcrel is equivalent to DW_EH_PE_absptr. For
+ reading the initial location of an FDE it should be treated
+ as such, and currently that's the only place where this code
+ is used. */
+ base = 0;
+ break;
case DW_EH_PE_aligned:
base = 0;
offset = buf - unit->dwarf_frame_buffer;
struct dwarf2_fde *fde;
CORE_ADDR offset;
- fde = objfile_data (objfile, dwarf2_frame_data);
+ fde = objfile_data (objfile, dwarf2_frame_objfile_data);
if (fde == NULL)
continue;
static void
add_fde (struct comp_unit *unit, struct dwarf2_fde *fde)
{
- fde->next = objfile_data (unit->objfile, dwarf2_frame_data);
- set_objfile_data (unit->objfile, dwarf2_frame_data, fde);
+ fde->next = objfile_data (unit->objfile, dwarf2_frame_objfile_data);
+ set_objfile_data (unit->objfile, dwarf2_frame_objfile_data, fde);
}
#ifdef CC_HAS_LONG_LONG
/* This is a CIE. */
struct dwarf2_cie *cie;
char *augmentation;
+ unsigned int cie_version;
/* Record the offset into the .debug_frame section of this CIE. */
cie_pointer = start - unit->dwarf_frame_buffer;
return end;
cie = (struct dwarf2_cie *)
- obstack_alloc (&unit->objfile->psymbol_obstack,
+ obstack_alloc (&unit->objfile->objfile_obstack,
sizeof (struct dwarf2_cie));
cie->initial_instructions = NULL;
cie->cie_pointer = cie_pointer;
cie->encoding = encoding_for_size (unit->addr_size);
/* Check version number. */
- if (read_1_byte (unit->abfd, buf) != DW_CIE_VERSION)
+ cie_version = read_1_byte (unit->abfd, buf);
+ if (cie_version != 1 && cie_version != 3)
return NULL;
buf += 1;
read_signed_leb128 (unit->abfd, buf, &bytes_read);
buf += bytes_read;
- cie->return_address_register = read_1_byte (unit->abfd, buf);
- buf += 1;
+ if (cie_version == 1)
+ {
+ cie->return_address_register = read_1_byte (unit->abfd, buf);
+ bytes_read = 1;
+ }
+ else
+ cie->return_address_register = read_unsigned_leb128 (unit->abfd, buf,
+ &bytes_read);
+ buf += bytes_read;
cie->saw_z_augmentation = (*augmentation == 'z');
if (cie->saw_z_augmentation)
return NULL;
fde = (struct dwarf2_fde *)
- obstack_alloc (&unit->objfile->psymbol_obstack,
+ obstack_alloc (&unit->objfile->objfile_obstack,
sizeof (struct dwarf2_fde));
fde->cie = find_cie (unit, cie_pointer);
if (fde->cie == NULL)
return ret;
}
-
\f
/* FIXME: kettenis/20030504: This still needs to be integrated with
void
_initialize_dwarf2_frame (void)
{
- dwarf2_frame_data = register_objfile_data ();
+ dwarf2_frame_data = gdbarch_data_register_pre_init (dwarf2_frame_init);
+ dwarf2_frame_objfile_data = register_objfile_data ();
}
projects / deliverable / binutils-gdb.git / blobdiff