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authorRichard Henderson <rth@redhat.com>2008-09-24 23:21:04 +0000
committerRichard Henderson <rth@redhat.com>2008-09-24 23:21:04 +0000
commitf1c4cc7516582b6fdb474d43c1b8e1b74dd73f52 (patch)
tree6f14d634455a6dc54e1db050f103bea47095686d /gas
parent6fbd21a1cee8c0f55252cd0f0c06423aaddaf70f (diff)
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include/
* elf/dwarf2.h (DW_OP_GNU_encoded_addr): New. binutils/ * dwarf.c (size_of_encoded_value, get_encoded_value): Move up. (decode_location_expression): Add section parameter. Handle DW_OP_GNU_encoded_addr. (read_and_display_attr_value): Update decode_location_expression call. (display_debug_loc, display_debug_frames): Likewise. gas/ * dw2gencfi.c (DWARF2_ADDR_SIZE): Provide default. (struct cfi_insn_data): Add ea member. (CFI_val_encoded_addr, dot_cfi_val_encoded_addr): New. (output_cfi_insn): Handle CFI_val_encoded_addr. (select_cie_for_fde): Don't match CFI_val_encoded_addr. * doc/as.texinfo (.cfi_val_encoded_addr): Document.
Diffstat (limited to 'gas')
-rw-r--r--gas/ChangeLog9
-rw-r--r--gas/doc/as.texinfo11
-rw-r--r--gas/dw2gencfi.c146
3 files changed, 162 insertions, 4 deletions
diff --git a/gas/ChangeLog b/gas/ChangeLog
index e305b2e..3d023df 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,12 @@
+2008-09-24 Richard Henderson <rth@redhat.com>
+
+ * dw2gencfi.c (DWARF2_ADDR_SIZE): Provide default.
+ (struct cfi_insn_data): Add ea member.
+ (CFI_val_encoded_addr, dot_cfi_val_encoded_addr): New.
+ (output_cfi_insn): Handle CFI_val_encoded_addr.
+ (select_cie_for_fde): Don't match CFI_val_encoded_addr.
+ * doc/as.texinfo (.cfi_val_encoded_addr): Document.
+
2008-09-25 Alan Modra <amodra@bigpond.net.au>
PR 6913
diff --git a/gas/doc/as.texinfo b/gas/doc/as.texinfo
index 92b4cde..c0aef5c 100644
--- a/gas/doc/as.texinfo
+++ b/gas/doc/as.texinfo
@@ -4230,6 +4230,17 @@ Allows the user to add arbitrary bytes to the unwind info. One
might use this to add OS-specific CFI opcodes, or generic CFI
opcodes that GAS does not yet support.
+@section @code{.cfi_val_encoded_addr @var{register}, @var{encoding}, @var{label}}
+The current value of @var{register} is @var{label}. The value of @var{label}
+will be encoded in the output file according to @var{encoding}; see the
+description of @code{.cfi_personality} for details on this encoding.
+
+The usefulness of equating a register to a fixed label is probably
+limited to the return address register. Here, it can be useful to
+mark a code segment that has only one return address which is reached
+by a direct branch and no copy of the return address exists in memory
+or another register.
+
@node LNS directives
@section @code{.file @var{fileno} @var{filename}}
@cindex @code{file} directive
diff --git a/gas/dw2gencfi.c b/gas/dw2gencfi.c
index 49a23ad..3cb5dff 100644
--- a/gas/dw2gencfi.c
+++ b/gas/dw2gencfi.c
@@ -58,6 +58,10 @@
# define tc_cfi_frame_initial_instructions() ((void)0)
#endif
+#ifndef DWARF2_ADDR_SIZE
+# define DWARF2_ADDR_SIZE(bfd) (bfd_arch_bits_per_address (bfd) / 8)
+#endif
+
struct cfi_insn_data
{
@@ -86,6 +90,11 @@ struct cfi_insn_data
struct cfi_escape_data *next;
expressionS exp;
} *esc;
+
+ struct {
+ unsigned reg, encoding;
+ expressionS exp;
+ } ea;
} u;
};
@@ -376,6 +385,7 @@ static void dot_cfi_startproc (int);
static void dot_cfi_endproc (int);
static void dot_cfi_personality (int);
static void dot_cfi_lsda (int);
+static void dot_cfi_val_encoded_addr (int);
/* Fake CFI type; outside the byte range of any real CFI insn. */
#define CFI_adjust_cfa_offset 0x100
@@ -383,6 +393,7 @@ static void dot_cfi_lsda (int);
#define CFI_rel_offset 0x102
#define CFI_escape 0x103
#define CFI_signal_frame 0x104
+#define CFI_val_encoded_addr 0x105
const pseudo_typeS cfi_pseudo_table[] =
{
@@ -406,6 +417,7 @@ const pseudo_typeS cfi_pseudo_table[] =
{ "cfi_signal_frame", dot_cfi, CFI_signal_frame },
{ "cfi_personality", dot_cfi_personality, 0 },
{ "cfi_lsda", dot_cfi_lsda, 0 },
+ { "cfi_val_encoded_addr", dot_cfi_val_encoded_addr, 0 },
{ NULL, NULL, 0 }
};
@@ -654,7 +666,7 @@ dot_cfi_personality (int ignored ATTRIBUTE_UNUSED)
}
fde = frchain_now->frch_cfi_data->cur_fde_data;
- encoding = get_absolute_expression ();
+ encoding = cfi_parse_const ();
if (encoding == DW_EH_PE_omit)
{
demand_empty_rest_of_line ();
@@ -724,7 +736,7 @@ dot_cfi_lsda (int ignored ATTRIBUTE_UNUSED)
}
fde = frchain_now->frch_cfi_data->cur_fde_data;
- encoding = get_absolute_expression ();
+ encoding = cfi_parse_const ();
if (encoding == DW_EH_PE_omit)
{
demand_empty_rest_of_line ();
@@ -783,6 +795,71 @@ dot_cfi_lsda (int ignored ATTRIBUTE_UNUSED)
}
static void
+dot_cfi_val_encoded_addr (int ignored ATTRIBUTE_UNUSED)
+{
+ struct cfi_insn_data *insn_ptr;
+ offsetT encoding;
+
+ if (frchain_now->frch_cfi_data == NULL)
+ {
+ as_bad (_("CFI instruction used without previous .cfi_startproc"));
+ ignore_rest_of_line ();
+ return;
+ }
+
+ /* If the last address was not at the current PC, advance to current. */
+ if (symbol_get_frag (frchain_now->frch_cfi_data->last_address) != frag_now
+ || S_GET_VALUE (frchain_now->frch_cfi_data->last_address)
+ != frag_now_fix ())
+ cfi_add_advance_loc (symbol_temp_new_now ());
+
+ insn_ptr = alloc_cfi_insn_data ();
+ insn_ptr->insn = CFI_val_encoded_addr;
+
+ insn_ptr->u.ea.reg = cfi_parse_reg ();
+
+ cfi_parse_separator ();
+ encoding = cfi_parse_const ();
+ if ((encoding & 0xff) != encoding
+ || ((encoding & 0x70) != 0
+#if CFI_DIFF_EXPR_OK || defined tc_cfi_emit_pcrel_expr
+ && (encoding & 0x70) != DW_EH_PE_pcrel
+#endif
+ )
+ /* leb128 can be handled, but does something actually need it? */
+ || (encoding & 7) == DW_EH_PE_uleb128
+ || (encoding & 7) > DW_EH_PE_udata8)
+ {
+ as_bad (_("invalid or unsupported encoding in .cfi_lsda"));
+ encoding = DW_EH_PE_omit;
+ }
+
+ cfi_parse_separator ();
+ expression_and_evaluate (&insn_ptr->u.ea.exp);
+ switch (insn_ptr->u.ea.exp.X_op)
+ {
+ case O_symbol:
+ break;
+ case O_constant:
+ if ((encoding & 0x70) != DW_EH_PE_pcrel)
+ break;
+ default:
+ encoding = DW_EH_PE_omit;
+ break;
+ }
+
+ insn_ptr->u.ea.encoding = encoding;
+ if (encoding == DW_EH_PE_omit)
+ {
+ as_bad (_("wrong third argument to .cfi_val_encoded_addr"));
+ ignore_rest_of_line ();
+ return;
+ }
+
+ demand_empty_rest_of_line ();
+}
+
+static void
dot_cfi_startproc (int ignored ATTRIBUTE_UNUSED)
{
int simple = 0;
@@ -1028,6 +1105,64 @@ output_cfi_insn (struct cfi_insn_data *insn)
break;
}
+ case CFI_val_encoded_addr:
+ {
+ unsigned encoding = insn->u.ea.encoding;
+ offsetT encoding_size;
+
+ if (encoding == DW_EH_PE_omit)
+ break;
+ out_one (DW_CFA_val_expression);
+ out_uleb128 (insn->u.ea.reg);
+
+ switch (encoding & 0x7)
+ {
+ case DW_EH_PE_absptr:
+ encoding_size = DWARF2_ADDR_SIZE (stdoutput);
+ break;
+ case DW_EH_PE_udata2:
+ encoding_size = 2;
+ break;
+ case DW_EH_PE_udata4:
+ encoding_size = 4;
+ break;
+ case DW_EH_PE_udata8:
+ encoding_size = 8;
+ break;
+ default:
+ abort ();
+ }
+
+ /* If the user has requested absolute encoding,
+ then use the smaller DW_OP_addr encoding. */
+ if (insn->u.ea.encoding == DW_EH_PE_absptr)
+ {
+ out_uleb128 (1 + encoding_size);
+ out_one (DW_OP_addr);
+ }
+ else
+ {
+ out_uleb128 (1 + 1 + encoding_size);
+ out_one (DW_OP_GNU_encoded_addr);
+ out_one (encoding);
+
+ if ((encoding & 0x70) == DW_EH_PE_pcrel)
+ {
+#if CFI_DIFF_EXPR_OK
+ insn->u.ea.exp.X_op = O_subtract;
+ insn->u.ea.exp.X_op_symbol = symbol_temp_new_now ();
+#elif defined (tc_cfi_emit_pcrel_expr)
+ tc_cfi_emit_pcrel_expr (&insn.u.ea.exp, encoding_size);
+ break;
+#else
+ abort ();
+#endif
+ }
+ }
+ emit_expr (&insn->u.ea.exp, encoding_size);
+ }
+ break;
+
default:
abort ();
}
@@ -1292,6 +1427,7 @@ select_cie_for_fde (struct fde_entry *fde, struct cfi_insn_data **pfirst)
break;
case CFI_escape:
+ case CFI_val_encoded_addr:
/* Don't bother matching these for now. */
goto fail;
@@ -1307,7 +1443,8 @@ select_cie_for_fde (struct fde_entry *fde, struct cfi_insn_data **pfirst)
&& (!j
|| j->insn == DW_CFA_advance_loc
|| j->insn == DW_CFA_remember_state
- || j->insn == CFI_escape))
+ || j->insn == CFI_escape
+ || j->insn == CFI_val_encoded_addr))
{
*pfirst = j;
return cie;
@@ -1329,7 +1466,8 @@ select_cie_for_fde (struct fde_entry *fde, struct cfi_insn_data **pfirst)
for (i = cie->first; i ; i = i->next)
if (i->insn == DW_CFA_advance_loc
|| i->insn == DW_CFA_remember_state
- || i->insn == CFI_escape)
+ || i->insn == CFI_escape
+ || i->insn == CFI_val_encoded_addr)
break;
cie->last = i;