}
-/* A prologue-value-esque boolean type, including "maybe", when we
- can't figure out whether something is true or not. */
-enum pv_boolean {
- pv_maybe,
- pv_definite_yes,
- pv_definite_no,
-};
-
-
-/* Decide whether a reference to SIZE bytes at ADDR refers exactly to
- an element of an array. The array starts at ARRAY_ADDR, and has
- ARRAY_LEN values of ELT_SIZE bytes each. If ADDR definitely does
- refer to an array element, set *I to the index of the referenced
- element in the array, and return pv_definite_yes. If it definitely
- doesn't, return pv_definite_no. If we can't tell, return pv_maybe.
-
- If the reference does touch the array, but doesn't fall exactly on
- an element boundary, or doesn't refer to the whole element, return
- pv_maybe. */
-static enum pv_boolean
-pv_is_array_ref (struct prologue_value *addr,
- CORE_ADDR size,
- struct prologue_value *array_addr,
- CORE_ADDR array_len,
- CORE_ADDR elt_size,
- int *i)
-{
- struct prologue_value offset;
-
- /* Note that, since ->k is a CORE_ADDR, and CORE_ADDR is unsigned,
- if addr is *before* the start of the array, then this isn't going
- to be negative... */
- pv_subtract (&offset, addr, array_addr);
-
- if (offset.kind == pv_constant)
- {
- /* This is a rather odd test. We want to know if the SIZE bytes
- at ADDR don't overlap the array at all, so you'd expect it to
- be an || expression: "if we're completely before || we're
- completely after". But with unsigned arithmetic, things are
- different: since it's a number circle, not a number line, the
- right values for offset.k are actually one contiguous range. */
- if (offset.k <= -size
- && offset.k >= array_len * elt_size)
- return pv_definite_no;
- else if (offset.k % elt_size != 0
- || size != elt_size)
- return pv_maybe;
- else
- {
- *i = offset.k / elt_size;
- return pv_definite_yes;
- }
- }
- else
- return pv_maybe;
-}
-
-
-
/* Decoding S/390 instructions. */
/* Named opcode values for the S/390 instructions we recognize. Some
}
-/* The number of GPR and FPR spill slots in an S/390 stack frame. We
- track general-purpose registers r2 -- r15, and floating-point
- registers f0, f2, f4, and f6. */
-#define S390_NUM_SPILL_SLOTS (14 + 4)
#define S390_NUM_GPRS 16
#define S390_NUM_FPRS 16
/* The floating-point registers. */
struct prologue_value fpr[S390_NUM_FPRS];
- /* The register spill stack slots in the caller's frame ---
- general-purpose registers r2 through r15, and floating-point
- registers. spill[i] is where gpr i+2 gets spilled;
- spill[(14, 15, 16, 17)] is where (f0, f2, f4, f6) get spilled. */
- struct prologue_value spill[S390_NUM_SPILL_SLOTS];
-
- /* The value of the back chain slot. This is only valid if the stack
- pointer is known to be less than its original value --- that is,
- if we have indeed allocated space on the stack. */
- struct prologue_value back_chain;
-};
+ /* The offset relative to the CFA where the incoming GPR N was saved
+ by the function prologue. 0 if not saved or unknown. */
+ int gpr_slot[S390_NUM_GPRS];
+ /* Likewise for FPRs. */
+ int fpr_slot[S390_NUM_FPRS];
-/* If the SIZE bytes at ADDR are a stack slot we're actually tracking,
- return pv_definite_yes and set *STACK to point to the slot. If
- we're sure that they are not any of our stack slots, then return
- pv_definite_no. Otherwise, return pv_maybe.
-
- DATA describes our current state (registers and stack slots). */
-static enum pv_boolean
-s390_on_stack (struct prologue_value *addr,
- CORE_ADDR size,
- struct s390_prologue_data *data,
- struct prologue_value **stack)
-{
- struct prologue_value gpr_spill_addr;
- struct prologue_value fpr_spill_addr;
- struct prologue_value back_chain_addr;
- int i;
- enum pv_boolean b;
-
- /* Construct the addresses of the spill arrays and the back chain. */
- pv_set_to_register (&gpr_spill_addr, S390_SP_REGNUM, 2 * data->gpr_size);
- pv_set_to_register (&fpr_spill_addr, S390_SP_REGNUM, 16 * data->gpr_size);
- back_chain_addr = data->gpr[S390_SP_REGNUM - S390_R0_REGNUM];
-
- /* We have to check for GPR and FPR references using two separate
- calls to pv_is_array_ref, since the GPR and FPR spill slots are
- different sizes. (SPILL is an array, but the thing it tracks
- isn't really an array.) */
-
- /* Was it a reference to the GPR spill array? */
- b = pv_is_array_ref (addr, size, &gpr_spill_addr, 14, data->gpr_size, &i);
- if (b == pv_definite_yes)
- {
- *stack = &data->spill[i];
- return pv_definite_yes;
- }
- if (b == pv_maybe)
- return pv_maybe;
-
- /* Was it a reference to the FPR spill array? */
- b = pv_is_array_ref (addr, size, &fpr_spill_addr, 4, data->fpr_size, &i);
- if (b == pv_definite_yes)
- {
- *stack = &data->spill[14 + i];
- return pv_definite_yes;
- }
- if (b == pv_maybe)
- return pv_maybe;
-
- /* Was it a reference to the back chain?
- This isn't quite right. We ought to check whether we have
- actually allocated any new frame at all. */
- b = pv_is_array_ref (addr, size, &back_chain_addr, 1, data->gpr_size, &i);
- if (b == pv_definite_yes)
- {
- *stack = &data->back_chain;
- return pv_definite_yes;
- }
- if (b == pv_maybe)
- return pv_maybe;
-
- /* All the above queries returned definite 'no's. */
- return pv_definite_no;
-}
-
+ /* Nonzero if the backchain was saved. This is assumed to be the
+ case when the incoming SP is saved at the current SP location. */
+ int back_chain_saved_p;
+};
/* Do a SIZE-byte store of VALUE to ADDR. */
static void
struct prologue_value *value,
struct s390_prologue_data *data)
{
- struct prologue_value *stack;
+ struct prologue_value cfa, offset;
+ int i;
- /* We can do it if it's definitely a reference to something on the stack. */
- if (s390_on_stack (addr, size, data, &stack) == pv_definite_yes)
+ /* Check whether we are storing the backchain. */
+ pv_subtract (&offset, &data->gpr[S390_SP_REGNUM - S390_R0_REGNUM], addr);
+
+ if (offset.kind == pv_constant && offset.k == 0)
+ if (size == data->gpr_size
+ && pv_is_register (value, S390_SP_REGNUM, 0))
+ {
+ data->back_chain_saved_p = 1;
+ return;
+ }
+
+
+ /* Check whether we are storing a register into the stack. */
+ pv_set_to_register (&cfa, S390_SP_REGNUM, 16 * data->gpr_size + 32);
+ pv_subtract (&offset, &cfa, addr);
+
+ if (offset.kind == pv_constant
+ && offset.k < INT_MAX && offset.k > 0
+ && offset.k % data->gpr_size == 0)
{
- *stack = *value;
- return;
+ /* If we are storing the original value of a register, we want to
+ record the CFA offset. If the same register is stored multiple
+ times, the stack slot with the highest address counts. */
+
+ for (i = 0; i < S390_NUM_GPRS; i++)
+ if (size == data->gpr_size
+ && pv_is_register (value, S390_R0_REGNUM + i, 0))
+ if (data->gpr_slot[i] == 0
+ || data->gpr_slot[i] > offset.k)
+ {
+ data->gpr_slot[i] = offset.k;
+ return;
+ }
+
+ for (i = 0; i < S390_NUM_FPRS; i++)
+ if (size == data->fpr_size
+ && pv_is_register (value, S390_F0_REGNUM + i, 0))
+ if (data->fpr_slot[i] == 0
+ || data->fpr_slot[i] > offset.k)
+ {
+ data->fpr_slot[i] = offset.k;
+ return;
+ }
}
- /* Note: If s390_on_stack returns pv_maybe, you might think we should
- forget our cached values, as any of those might have been hit.
- However, we make the assumption that --since the fields we track
- are save areas private to compiler, and never directly exposed to
- the user-- every access to our data is explicit. Hence, every
- memory access we cannot follow can't hit our data. */
+ /* Note: If this is some store we cannot identify, you might think we
+ should forget our cached values, as any of those might have been hit.
+
+ However, we make the assumption that the register save areas are only
+ ever stored to once in any given function, and we do recognize these
+ stores. Thus every store we cannot recognize does not hit our data. */
}
/* Do a SIZE-byte load from ADDR into VALUE. */
struct prologue_value *value,
struct s390_prologue_data *data)
{
- struct prologue_value *stack;
+ struct prologue_value cfa, offset;
+ int i;
/* If it's a load from an in-line constant pool, then we can
simulate that, under the assumption that the code isn't
}
}
- /* If it's definitely a reference to something on the stack,
- we can do that. */
- if (s390_on_stack (addr, size, data, &stack) == pv_definite_yes)
+ /* Check whether we are accessing one of our save slots. */
+ pv_set_to_register (&cfa, S390_SP_REGNUM, 16 * data->gpr_size + 32);
+ pv_subtract (&offset, &cfa, addr);
+
+ if (offset.kind == pv_constant
+ && offset.k < INT_MAX && offset.k > 0)
{
- *value = *stack;
- return;
+ for (i = 0; i < S390_NUM_GPRS; i++)
+ if (offset.k == data->gpr_slot[i])
+ {
+ pv_set_to_register (value, S390_R0_REGNUM + i, 0);
+ return;
+ }
+
+ for (i = 0; i < S390_NUM_FPRS; i++)
+ if (offset.k == data->fpr_slot[i])
+ {
+ pv_set_to_register (value, S390_F0_REGNUM + i, 0);
+ return;
+ }
}
/* Otherwise, we don't know the value. */
for (i = 0; i < S390_NUM_FPRS; i++)
pv_set_to_register (&data->fpr[i], S390_F0_REGNUM + i, 0);
- for (i = 0; i < S390_NUM_SPILL_SLOTS; i++)
- pv_set_to_unknown (&data->spill[i]);
+ for (i = 0; i < S390_NUM_GPRS; i++)
+ data->gpr_slot[i] = 0;
+
+ for (i = 0; i < S390_NUM_FPRS; i++)
+ data->fpr_slot[i] = 0;
- pv_set_to_unknown (&data->back_chain);
+ data->back_chain_saved_p = 0;
}
/* Start interpreting instructions, until we hit the frame's
unsigned int b2, r1, r2, x2, r3;
int i2, d2;
- /* The values of SP, FP, and back chain before this instruction,
+ /* The values of SP and FP before this instruction,
for detecting instructions that change them. */
- struct prologue_value pre_insn_sp, pre_insn_fp, pre_insn_back_chain;
+ struct prologue_value pre_insn_sp, pre_insn_fp;
+ /* Likewise for the flag whether the back chain was saved. */
+ int pre_insn_back_chain_saved_p;
/* If we got an error trying to read the instruction, report it. */
if (insn_len < 0)
pre_insn_sp = data->gpr[S390_SP_REGNUM - S390_R0_REGNUM];
pre_insn_fp = data->gpr[S390_FRAME_REGNUM - S390_R0_REGNUM];
- pre_insn_back_chain = data->back_chain;
+ pre_insn_back_chain_saved_p = data->back_chain_saved_p;
/* LHI r1, i2 --- load halfword immediate */
if (word_size == 4
&& ! pv_is_register (sp, S390_SP_REGNUM, 0))
|| (! pv_is_identical (&pre_insn_fp, fp)
&& ! pv_is_register (fp, S390_FRAME_REGNUM, 0))
- || ! pv_is_identical (&pre_insn_back_chain, &data->back_chain))
+ || pre_insn_back_chain_saved_p != data->back_chain_saved_p)
result = next_pc;
}
}
struct s390_unwind_cache *info)
{
struct gdbarch *gdbarch = get_frame_arch (next_frame);
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
int word_size = gdbarch_ptr_bit (gdbarch) / 8;
struct s390_prologue_data data;
struct prologue_value *fp = &data.gpr[S390_FRAME_REGNUM - S390_R0_REGNUM];
struct prologue_value *sp = &data.gpr[S390_SP_REGNUM - S390_R0_REGNUM];
- int slot_num;
- CORE_ADDR slot_addr;
+ int i;
+ CORE_ADDR cfa;
CORE_ADDR func;
CORE_ADDR result;
ULONGEST reg;
add back the frame size to arrive that the previous frame's
stack pointer value. */
prev_sp = frame_unwind_register_unsigned (next_frame, frame_pointer) + size;
+ cfa = prev_sp + 16*word_size + 32;
- /* Scan the spill array; if a spill slot says it holds the
- original value of some register, then record that slot's
- address as the place that register was saved. */
-
- /* Slots for %r2 .. %r15. */
- for (slot_num = 0, slot_addr = prev_sp + 2 * data.gpr_size;
- slot_num < 14;
- slot_num++, slot_addr += data.gpr_size)
- {
- struct prologue_value *slot = &data.spill[slot_num];
+ /* Record the addresses of all register spill slots the prologue parser
+ has recognized. Consider only registers defined as call-saved by the
+ ABI; for call-clobbered registers the parser may have recognized
+ spurious stores. */
- if (slot->kind == pv_register
- && slot->k == 0)
- info->saved_regs[slot->reg].addr = slot_addr;
- }
+ for (i = 6; i <= 15; i++)
+ if (data.gpr_slot[i] != 0)
+ info->saved_regs[S390_R0_REGNUM + i].addr = cfa - data.gpr_slot[i];
- /* Slots for %f0 .. %f6. */
- for (slot_num = 14, slot_addr = prev_sp + 16 * data.gpr_size;
- slot_num < S390_NUM_SPILL_SLOTS;
- slot_num++, slot_addr += data.fpr_size)
+ switch (tdep->abi)
{
- struct prologue_value *slot = &data.spill[slot_num];
+ case ABI_LINUX_S390:
+ if (data.fpr_slot[4] != 0)
+ info->saved_regs[S390_F4_REGNUM].addr = cfa - data.fpr_slot[4];
+ if (data.fpr_slot[6] != 0)
+ info->saved_regs[S390_F6_REGNUM].addr = cfa - data.fpr_slot[6];
+ break;
- if (slot->kind == pv_register
- && slot->k == 0)
- info->saved_regs[slot->reg].addr = slot_addr;
+ case ABI_LINUX_ZSERIES:
+ for (i = 8; i <= 15; i++)
+ if (data.fpr_slot[i] != 0)
+ info->saved_regs[S390_F0_REGNUM + i].addr = cfa - data.fpr_slot[i];
+ break;
}
/* Function return will set PC to %r14. */
and the back chain pointer. */
sp -= 16*word_size + 32;
- /* Write the back chain pointer into the first word of the stack
- frame. This is needed to unwind across a dummy frame. */
- regcache_cooked_read_unsigned (regcache, S390_SP_REGNUM, &orig_sp);
- write_memory_unsigned_integer (sp, word_size, orig_sp);
-
/* Store return address. */
regcache_cooked_write_unsigned (regcache, S390_RETADDR_REGNUM, bp_addr);
regcache_cooked_write_unsigned (regcache, S390_SP_REGNUM, sp);
/* We need to return the 'stack part' of the frame ID,
- which is actually the top of the register save area
- allocated on the original stack. */
- return orig_sp + 16*word_size + 32;
+ which is actually the top of the register save area. */
+ return sp + 16*word_size + 32;
}
/* Assuming NEXT_FRAME->prev is a dummy, return the frame ID of that
s390_unwind_dummy_id (struct gdbarch *gdbarch, struct frame_info *next_frame)
{
int word_size = gdbarch_ptr_bit (gdbarch) / 8;
- CORE_ADDR this_sp = s390_unwind_sp (gdbarch, next_frame);
- CORE_ADDR prev_sp = read_memory_unsigned_integer (this_sp, word_size);
+ CORE_ADDR sp = s390_unwind_sp (gdbarch, next_frame);
- return frame_id_build (prev_sp + 16*word_size + 32,
+ return frame_id_build (sp + 16*word_size + 32,
frame_pc_unwind (next_frame));
}
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