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-rw-r--r--gcc/unwind-dw2.c95
1 files changed, 70 insertions, 25 deletions
diff --git a/gcc/unwind-dw2.c b/gcc/unwind-dw2.c
index 3c5feea4e03..6d7219eeca1 100644
--- a/gcc/unwind-dw2.c
+++ b/gcc/unwind-dw2.c
@@ -1,5 +1,5 @@
/* DWARF2 exception handling and frame unwind runtime interface routines.
- Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002
+ Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003
Free Software Foundation, Inc.
This file is part of GCC.
@@ -166,6 +166,14 @@ _Unwind_GetGR (struct _Unwind_Context *context, int index)
return * (_Unwind_Word *) context->reg[index];
}
+/* Get the value of the CFA as saved in CONTEXT. */
+
+_Unwind_Word
+_Unwind_GetCFA (struct _Unwind_Context *context)
+{
+ return (_Unwind_Ptr) context->cfa;
+}
+
/* Overwrite the saved value for register REG in CONTEXT with VAL. */
inline void
@@ -692,7 +700,7 @@ execute_stack_op (const unsigned char *op_ptr, const unsigned char *op_end,
/* Most things push a result value. */
if ((size_t) stack_elt >= sizeof(stack)/sizeof(*stack))
abort ();
- stack[++stack_elt] = result;
+ stack[stack_elt++] = result;
no_push:;
}
@@ -782,6 +790,9 @@ execute_cfa_program (const unsigned char *insn_ptr,
case DW_CFA_undefined:
case DW_CFA_same_value:
+ insn_ptr = read_uleb128 (insn_ptr, &reg);
+ break;
+
case DW_CFA_nop:
break;
@@ -839,17 +850,17 @@ execute_cfa_program (const unsigned char *insn_ptr,
break;
case DW_CFA_def_cfa_expression:
- insn_ptr = read_uleb128 (insn_ptr, &utmp);
fs->cfa_exp = insn_ptr;
fs->cfa_how = CFA_EXP;
+ insn_ptr = read_uleb128 (insn_ptr, &utmp);
insn_ptr += utmp;
break;
case DW_CFA_expression:
insn_ptr = read_uleb128 (insn_ptr, &reg);
- insn_ptr = read_uleb128 (insn_ptr, &utmp);
fs->regs.reg[reg].how = REG_SAVED_EXP;
fs->regs.reg[reg].loc.exp = insn_ptr;
+ insn_ptr = read_uleb128 (insn_ptr, &utmp);
insn_ptr += utmp;
break;
@@ -1038,34 +1049,48 @@ uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
void *cfa;
long i;
+#ifdef EH_RETURN_STACKADJ_RTX
+ /* Special handling here: Many machines do not use a frame pointer,
+ and track the CFA only through offsets from the stack pointer from
+ one frame to the next. In this case, the stack pointer is never
+ stored, so it has no saved address in the context. What we do
+ have is the CFA from the previous stack frame.
+
+ In very special situations (such as unwind info for signal return),
+ there may be location expressions that use the stack pointer as well.
+
+ Do this conditionally for one frame. This allows the unwind info
+ for one frame to save a copy of the stack pointer from the previous
+ frame, and be able to use much easier CFA mechanisms to do it.
+ Always zap the saved stack pointer value for the next frame; carrying
+ the value over from one frame to another doesn't make sense. */
+
+ _Unwind_Word tmp_sp;
+
+ if (!orig_context.reg[__builtin_dwarf_sp_column ()])
+ {
+ tmp_sp = (_Unwind_Ptr) context->cfa;
+ orig_context.reg[__builtin_dwarf_sp_column ()] = &tmp_sp;
+ }
+ context->reg[__builtin_dwarf_sp_column ()] = NULL;
+#endif
+
/* Compute this frame's CFA. */
switch (fs->cfa_how)
{
case CFA_REG_OFFSET:
- /* Special handling here: Many machines do not use a frame pointer,
- and track the CFA only through offsets from the stack pointer from
- one frame to the next. In this case, the stack pointer is never
- stored, so it has no saved address in the context. What we do
- have is the CFA from the previous stack frame. */
- if (context->reg[fs->cfa_reg] == NULL)
- cfa = context->cfa;
- else
- cfa = (void *) (_Unwind_Ptr) _Unwind_GetGR (context, fs->cfa_reg);
+ cfa = (void *) (_Unwind_Ptr) _Unwind_GetGR (&orig_context, fs->cfa_reg);
cfa += fs->cfa_offset;
break;
case CFA_EXP:
- /* ??? No way of knowing what register number is the stack pointer
- to do the same sort of handling as above. Assume that if the
- CFA calculation is so complicated as to require a stack program
- that this will not be a problem. */
{
const unsigned char *exp = fs->cfa_exp;
_Unwind_Word len;
exp = read_uleb128 (exp, &len);
cfa = (void *) (_Unwind_Ptr)
- execute_stack_op (exp, exp + len, context, 0);
+ execute_stack_op (exp, exp + len, &orig_context, 0);
break;
}
@@ -1080,12 +1105,15 @@ uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
{
case REG_UNSAVED:
break;
+
case REG_SAVED_OFFSET:
context->reg[i] = cfa + fs->regs.reg[i].loc.offset;
break;
+
case REG_SAVED_REG:
context->reg[i] = orig_context.reg[fs->regs.reg[i].loc.reg];
break;
+
case REG_SAVED_EXP:
{
const unsigned char *exp = fs->regs.reg[i].loc.exp;
@@ -1137,6 +1165,7 @@ uw_init_context_1 (struct _Unwind_Context *context,
{
void *ra = __builtin_extract_return_addr (__builtin_return_address (0));
_Unwind_FrameState fs;
+ _Unwind_Word sp_slot;
memset (context, 0, sizeof (struct _Unwind_Context));
context->ra = ra;
@@ -1145,9 +1174,10 @@ uw_init_context_1 (struct _Unwind_Context *context,
abort ();
/* Force the frame state to use the known cfa value. */
- context->cfa = outer_cfa;
+ sp_slot = (_Unwind_Ptr) outer_cfa;
+ context->reg[__builtin_dwarf_sp_column ()] = &sp_slot;
fs.cfa_how = CFA_REG_OFFSET;
- fs.cfa_reg = 0;
+ fs.cfa_reg = __builtin_dwarf_sp_column ();
fs.cfa_offset = 0;
uw_update_context_1 (context, &fs);
@@ -1204,11 +1234,26 @@ uw_install_context_1 (struct _Unwind_Context *current,
memcpy (c, t, dwarf_reg_size_table[i]);
}
- /* We adjust SP by the difference between CURRENT and TARGET's CFA. */
- if (STACK_GROWS_DOWNWARD)
- return target->cfa - current->cfa + target->args_size;
- else
- return current->cfa - target->cfa - target->args_size;
+#ifdef EH_RETURN_STACKADJ_RTX
+ {
+ void *target_cfa;
+
+ /* If the last frame records a saved stack pointer, use it. */
+ if (target->reg[__builtin_dwarf_sp_column ()])
+ target_cfa = (void *)(_Unwind_Ptr)
+ _Unwind_GetGR (target, __builtin_dwarf_sp_column ());
+ else
+ target_cfa = target->cfa;
+
+ /* We adjust SP by the difference between CURRENT and TARGET's CFA. */
+ if (STACK_GROWS_DOWNWARD)
+ return target_cfa - current->cfa + target->args_size;
+ else
+ return current->cfa - target_cfa - target->args_size;
+ }
+#else
+ return 0;
+#endif
}
static inline _Unwind_Ptr
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-01 22:52:53 +0000