#include "bfd.h"
#include "gdb_string.h"
#include "gdbcore.h"
+#include "symfile.h"
+
+/* Dummy frame. This saves the processor state just prior to setting up the
+ inferior function call. On most targets, the registers are saved on the
+ target stack, but that really slows down function calls. */
struct dummy_frame
{
struct dummy_frame *next;
- CORE_ADDR fp;
- CORE_ADDR sp;
- CORE_ADDR rp;
- CORE_ADDR pc;
+ char regs[REGISTER_BYTES];
};
static struct dummy_frame *dummy_frame_stack = NULL;
-\f
-/* This function actually figures out the frame address for a given pc and
- sp. This is tricky on the v850 because we only use an explicit frame
- pointer when using alloca(). The only reliable way to get this info is to
- examine the prologue.
-*/
-void
-v850_init_extra_frame_info (fi)
- struct frame_info *fi;
+static CORE_ADDR read_register_dummy PARAMS ((int regno));
+
+/* Info gleaned from scanning a function's prologue. */
+
+struct prologue_info
{
- struct symtab_and_line sal;
- CORE_ADDR func_addr, prologue_end, current_pc;
- int reg;
- int frameoffset;
int framereg;
+ int frameoffset;
+ int start_function;
+ struct frame_saved_regs *fsr;
+};
- if (fi->next)
- fi->pc = FRAME_SAVED_PC (fi->next);
+static CORE_ADDR scan_prologue PARAMS ((CORE_ADDR pc, struct prologue_info *fs));
+\f
+/* Scan the prologue of the function that contains PC, and record what we find
+ in PI. PI->fsr must be zeroed by the called. Returns the pc after the
+ prologue. Note that the addresses saved in pi->fsr are actually just frame
+ relative (negative offsets from the frame pointer). This is because we
+ don't know the actual value of the frame pointer yet. In some
+ circumstances, the frame pointer can't be determined till after we have
+ scanned the prologue. */
+
+static CORE_ADDR
+scan_prologue (pc, pi)
+ CORE_ADDR pc;
+ struct prologue_info *pi;
+{
+ CORE_ADDR func_addr, prologue_end, current_pc;
+ int fp_used;
/* First, figure out the bounds of the prologue so that we can limit the
search to something reasonable. */
- if (find_pc_partial_function (fi->pc, NULL, &func_addr, NULL))
+ if (find_pc_partial_function (pc, NULL, &func_addr, NULL))
{
+ struct symtab_and_line sal;
+
sal = find_pc_line (func_addr, 0);
+ if (func_addr == entry_point_address ())
+ pi->start_function = 1;
+ else
+ pi->start_function = 0;
+
if (sal.line == 0)
- prologue_end = fi->pc;
+ prologue_end = pc;
else
prologue_end = sal.end;
}
else
- prologue_end = func_addr + 100; /* We're in the boondocks */
+ { /* We're in the boondocks */
+ func_addr = pc - 100;
+ prologue_end = pc;
+ }
- prologue_end = min (prologue_end, fi->pc);
+ prologue_end = min (prologue_end, pc);
/* Now, search the prologue looking for instructions that setup fp, save
- rp, adjust sp and such. */
+ rp, adjust sp and such. We also record the frame offset of any saved
+ registers. */
- framereg = SP_REGNUM;
- frameoffset = 0;
- memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs);
+ pi->frameoffset = 0;
+ pi->framereg = SP_REGNUM;
+ fp_used = 0;
for (current_pc = func_addr; current_pc < prologue_end; current_pc += 2)
{
insn = read_memory_unsigned_integer (current_pc, 2);
if ((insn & 0xffe0) == ((SP_REGNUM << 11) | 0x0240)) /* add <imm>,sp */
- frameoffset = ((insn & 0x1f) ^ 0x10) - 0x10;
+ pi->frameoffset = ((insn & 0x1f) ^ 0x10) - 0x10;
else if (insn == ((SP_REGNUM << 11) | 0x0600 | SP_REGNUM)) /* addi <imm>,sp,sp */
- frameoffset = read_memory_integer (current_pc + 2, 2);
- else if (insn == ((FP_REGNUM << 11) | 0x0000 | 12)) /* mov r12,r2 */
- framereg = FP_REGNUM; /* Setting up fp */
- else if ((insn & 0x07ff) == (0x0760 | SP_REGNUM)) /* st.w <reg>,<offset>[sp] */
+ pi->frameoffset = read_memory_integer (current_pc + 2, 2);
+ else if (insn == ((FP_REGNUM << 11) | 0x0000 | 12)) /* mov r12,fp */
{
- reg = (insn >> 11) & 0x1f; /* Extract <reg> */
+ fp_used = 1;
+ pi->framereg = FP_REGNUM;
+ }
+ else if ((insn & 0x07ff) == (0x0760 | SP_REGNUM) /* st.w <reg>,<offset>[sp] */
+ || (fp_used
+ && (insn & 0x07ff) == (0x0760 | FP_REGNUM))) /* st.w <reg>,<offset>[fp] */
+ if (pi->fsr)
+ {
+ int framereg;
+ int reg;
+ int offset;
- insn = read_memory_integer (current_pc + 2, 2) & ~1;
+ framereg = insn & 0x1f;
+ reg = (insn >> 11) & 0x1f; /* Extract <reg> */
- fi->fsr.regs[reg] = insn + frameoffset;
- }
- else if ((insn & 0x07ff) == (0x0760 | FP_REGNUM)) /* st.w <reg>,<offset>[fp] */
- {
- reg = (insn >> 11) & 0x1f; /* Extract <reg> */
+ offset = read_memory_integer (current_pc + 2, 2) & ~1;
- insn = read_memory_integer (current_pc + 2, 2) & ~1;
+ if (framereg == SP_REGNUM) /* Using SP? */
+ offset += pi->frameoffset; /* Yes, correct for frame size */
- fi->fsr.regs[reg] = insn;
- }
+ pi->fsr->regs[reg] = offset;
+ }
if ((insn & 0x0780) >= 0x0600) /* Four byte instruction? */
current_pc += 2;
}
- if (PC_IN_CALL_DUMMY (fi->pc, NULL, NULL))
- fi->frame = dummy_frame_stack->sp;
- else if (!fi->next && framereg == SP_REGNUM)
- fi->frame = read_register (framereg) - frameoffset;
-
- for (reg = 0; reg < NUM_REGS; reg++)
- if (fi->fsr.regs[reg] != 0)
- fi->fsr.regs[reg] += fi->frame;
+ return current_pc;
}
-/* Find the caller of this frame. We do this by seeing if RP_REGNUM is saved
- in the stack anywhere, otherwise we get it from the registers. */
+/* Setup the frame frame pointer, pc, and frame addresses for saved registers.
+ Most of the work is done in scan_prologue().
-CORE_ADDR
-v850_find_callers_reg (fi, regnum)
+ Note that when we are called for the last frame (currently active frame),
+ that fi->pc and fi->frame will already be setup. However, fi->frame will
+ be valid only if this routine uses FP. For previous frames, fi-frame will
+ always be correct (since that is derived from v850_frame_chain ()).
+
+ We can be called with the PC in the call dummy under two circumstances.
+ First, during normal backtracing, second, while figuring out the frame
+ pointer just prior to calling the target function (see run_stack_dummy).
+ */
+
+void
+v850_init_extra_frame_info (fi)
struct frame_info *fi;
- int regnum;
{
- /* XXX - Won't work if multiple dummy frames are active */
+ struct prologue_info pi;
+ int reg;
+
+ if (fi->next)
+ fi->pc = FRAME_SAVED_PC (fi->next);
+
+ memset (fi->fsr.regs, '\000', sizeof fi->fsr.regs);
+
+ /* The call dummy doesn't save any registers on the stack, so we can return
+ now. */
if (PC_IN_CALL_DUMMY (fi->pc, NULL, NULL))
- switch (regnum)
- {
- case SP_REGNUM:
- return dummy_frame_stack->sp;
- break;
- case FP_REGNUM:
- return dummy_frame_stack->fp;
- break;
- case RP_REGNUM:
- return dummy_frame_stack->pc;
- break;
- case PC_REGNUM:
- return dummy_frame_stack->pc;
- break;
- }
+ {
+ /* We need to setup fi->frame here because run_stack_dummy gets it wrong
+ by assuming it's always FP. */
+ fi->frame = read_register_dummy (SP_REGNUM);
+ return;
+ }
- for (; fi; fi = fi->next)
- if (fi->fsr.regs[regnum] != 0)
- return read_memory_integer (fi->fsr.regs[regnum], 4);
+ pi.fsr = &fi->fsr;
- return read_register (regnum);
+ scan_prologue (fi->pc, &pi);
+
+ if (!fi->next && pi.framereg == SP_REGNUM)
+ fi->frame = read_register (pi.framereg) - pi.frameoffset;
+
+ for (reg = 0; reg < NUM_REGS; reg++)
+ if (fi->fsr.regs[reg] != 0)
+ fi->fsr.regs[reg] += fi->frame;
}
+/* Figure out the frame prior to FI. Unfortunately, this involves scanning the
+ prologue of the caller, which will also be done shortly by
+ v850_init_extra_frame_info. For the dummy frame, we just return the stack
+ pointer that was in use at the time the function call was made. */
+
CORE_ADDR
v850_frame_chain (fi)
struct frame_info *fi;
{
- CORE_ADDR callers_pc, callers_sp;
- CORE_ADDR func_addr, prologue_end, current_pc;
- int frameoffset;
+ CORE_ADDR callers_pc;
+ struct prologue_info pi;
/* First, find out who called us */
callers_pc = FRAME_SAVED_PC (fi);
if (PC_IN_CALL_DUMMY (callers_pc, NULL, NULL))
- return dummy_frame_stack->sp; /* XXX Won't work if multiple dummy frames on stack! */
+ return read_register_dummy (SP_REGNUM); /* XXX Won't work if multiple dummy frames on stack! */
- /* Next, figure out where his prologue is. */
+ pi.fsr = NULL;
- if (find_pc_partial_function (callers_pc, NULL, &func_addr, NULL))
- {
- struct symtab_and_line sal;
+ scan_prologue (callers_pc, &pi);
- /* Stop when the caller is the entry point function */
- if (func_addr == entry_point_address ())
- return 0;
+ if (pi.start_function)
+ return 0; /* Don't chain beyond the start function */
- sal = find_pc_line (func_addr, 0);
+ if (pi.framereg == FP_REGNUM)
+ return v850_find_callers_reg (fi, pi.framereg);
- if (sal.line == 0)
- prologue_end = callers_pc;
- else
- prologue_end = sal.end;
- }
- else
- prologue_end = func_addr + 100; /* We're in the boondocks */
-
- prologue_end = min (prologue_end, callers_pc);
-
- /* Now, figure out the frame location of the caller by examining his prologue.
- We're looking for either a load of the frame pointer register, or a stack
- adjustment. */
-
- frameoffset = 0;
-
- for (current_pc = func_addr; current_pc < prologue_end; current_pc += 2)
- {
- int insn;
+ return fi->frame - pi.frameoffset;
+}
- insn = read_memory_unsigned_integer (current_pc, 2);
+/* Find REGNUM on the stack. Otherwise, it's in an active register. One thing
+ we might want to do here is to check REGNUM against the clobber mask, and
+ somehow flag it as invalid if it isn't saved on the stack somewhere. This
+ would provide a graceful failure mode when trying to get the value of
+ caller-saves registers for an inner frame. */
- if ((insn & 0xffe0) == ((SP_REGNUM << 11) | 0x0240)) /* add <imm>,sp */
- frameoffset = ((insn & 0x1f) ^ 0x10) - 0x10;
- else if (insn == ((SP_REGNUM << 11) | 0x0600 | SP_REGNUM)) /* addi <imm>,sp,sp */
- frameoffset = read_memory_integer (current_pc + 2, 2);
- else if (insn == ((FP_REGNUM << 11) | 0x0000 | 12)) /* mov r12,r2 */
- return v850_find_callers_reg (fi, FP_REGNUM); /* It's using a frame pointer reg */
+CORE_ADDR
+v850_find_callers_reg (fi, regnum)
+ struct frame_info *fi;
+ int regnum;
+{
+ /* XXX - Won't work if multiple dummy frames are active */
+ /* When the caller requests RP from the dummy frame, we return PC because
+ that's where the previous routine appears to have done a call from. */
+ if (PC_IN_CALL_DUMMY (fi->pc, NULL, NULL))
+ if (regnum == RP_REGNUM)
+ regnum = PC_REGNUM;
- if ((insn & 0x0780) >= 0x0600) /* Four byte instruction? */
- current_pc += 2;
- }
+ for (; fi; fi = fi->next)
+ if (PC_IN_CALL_DUMMY (fi->pc, NULL, NULL))
+ return read_register_dummy (regnum);
+ else if (fi->fsr.regs[regnum] != 0)
+ return read_memory_integer (fi->fsr.regs[regnum], 4);
- return fi->frame - frameoffset;
+ return read_register (regnum);
}
CORE_ADDR
return pc;
}
-/* All we do here is record SP and FP on the call dummy stack */
+/* Save all the registers on the dummy frame stack. Most ports save the
+ registers on the target stack. This results in lots of unnecessary memory
+ references, which are slow when debugging via a serial line. Instead, we
+ save all the registers internally, and never write them to the stack. The
+ registers get restored when the called function returns to the entry point,
+ where a breakpoint is laying in wait. */
void
v850_push_dummy_frame ()
dummy_frame = xmalloc (sizeof (struct dummy_frame));
- dummy_frame->fp = read_register (FP_REGNUM);
- dummy_frame->sp = read_register (SP_REGNUM);
- dummy_frame->rp = read_register (RP_REGNUM);
- dummy_frame->pc = read_register (PC_REGNUM);
+ read_register_bytes (0, dummy_frame->regs, REGISTER_BYTES);
+
dummy_frame->next = dummy_frame_stack;
dummy_frame_stack = dummy_frame;
}
+/* Read registers from the topmost dummy frame. */
+
+CORE_ADDR
+read_register_dummy (regno)
+ int regno;
+{
+ return extract_address (&dummy_frame_stack->regs[REGISTER_BYTE (regno)],
+ REGISTER_RAW_SIZE(regno));
+}
+
int
v850_pc_in_call_dummy (pc)
CORE_ADDR pc;
&& pc <= CALL_DUMMY_ADDRESS () + DECR_PC_AFTER_BREAK;
}
+/* This routine gets called when either the user uses the `return' command, or
+ the call dummy breakpoint gets hit. */
+
struct frame_info *
v850_pop_frame (frame)
struct frame_info *frame;
dummy_frame_stack = dummy_frame->next;
- write_register (FP_REGNUM, dummy_frame->fp);
- write_register (SP_REGNUM, dummy_frame->sp);
- write_register (RP_REGNUM, dummy_frame->rp);
- write_register (PC_REGNUM, dummy_frame->pc);
+ write_register_bytes (0, dummy_frame->regs, REGISTER_BYTES);
free (dummy_frame);
-
- flush_cached_frames ();
-
- return NULL;
}
+ else
+ {
+ write_register (PC_REGNUM, FRAME_SAVED_PC (frame));
- write_register (PC_REGNUM, FRAME_SAVED_PC (frame));
+ for (regnum = 0; regnum < NUM_REGS; regnum++)
+ if (frame->fsr.regs[regnum] != 0)
+ write_register (regnum,
+ read_memory_integer (frame->fsr.regs[regnum], 4));
- for (regnum = 0; regnum < NUM_REGS; regnum++)
- if (frame->fsr.regs[regnum] != 0)
- write_register (regnum, read_memory_integer (frame->fsr.regs[regnum], 4));
+ write_register (SP_REGNUM, FRAME_FP (frame));
+ }
- write_register (SP_REGNUM, FRAME_FP (frame));
flush_cached_frames ();
return NULL;
}
-/* Put arguments in the right places, and setup return address register (RP) to
- point at a convenient place to put a breakpoint. First four args go in
+/* Setup arguments and RP for a call to the target. First four args go in
R6->R9, subsequent args go into sp + 16 -> sp + ... Structs are passed by
reference. 64 bit quantities (doubles and long longs) may be split between
the regs and the stack. When calling a function that returns a struct, a
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