[binutils-gdb] RISC-V: Stop generating mapping symbol $x, replace with $x<isa>.
Nelson Chu
nelsonc1225@sourceware.org
Mon Mar 3 03:38:48 GMT 2025
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=759b09f492d764edfba15c49d12a6f8adfeda019
commit 759b09f492d764edfba15c49d12a6f8adfeda019
Author: Nelson Chu <nelson@rivosinc.com>
Date: Mon Feb 24 15:36:53 2025 +0800
RISC-V: Stop generating mapping symbol $x, replace with $x<isa>.
The psABI defined $x to the architecture which is same as the file elf
attribute. But GNU defined it to that is same as the previous $x<isa>,
and always generated $x<isa> at the begining of each section. That is
because considering two objects have different architecture in their elf
attributes, then $x will always be wrong after linking since the merged
arch string will be changed. For example, object A with rv32ic and object
B with rv32ia, $x from A is rv32ic and $x from B is rv32ia, but the final
output is rv32ica, so $x from A and B need to be updated to rv32ic and
rv32ia by linker respectively. I think let linker to do this is not good,
so in order to follow the psABI, we will stop generating the $x for now.
Instead, all $x will be replaced with the corresponding $x<isa>. The
dis-assembler will also treat $x like what psABI defined.
Diff:
---
gas/config/tc-riscv.c | 51 ++++++++++++++++---------------
gas/testsuite/gas/riscv/mapping-symbols.d | 7 ++---
2 files changed, 30 insertions(+), 28 deletions(-)
diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
index 493c393f5b2..ca269bd9a46 100644
--- a/gas/config/tc-riscv.c
+++ b/gas/config/tc-riscv.c
@@ -531,15 +531,12 @@ make_mapping_symbol (enum riscv_seg_mstate state,
name = "$d";
break;
case MAP_INSN:
- if (arch_str != NULL)
- {
- size_t size = strlen (arch_str) + 3; /* "$x" + '\0' */
- buff = xmalloc (size);
- snprintf (buff, size, "$x%s", arch_str);
- name = buff;
- }
- else
- name = "$x";
+ gas_assert (arch_str);
+
+ size_t size = strlen (arch_str) + 3; /* "$x" + '\0' */
+ buff = xmalloc (size);
+ snprintf (buff, size, "$x%s", arch_str);
+ name = buff;
break;
default:
abort ();
@@ -585,11 +582,22 @@ make_mapping_symbol (enum riscv_seg_mstate state,
if (odd_data_padding)
{
- /* If the removed mapping symbol is $x+arch, then add it back to
- the next $x. */
- const char *str = removed != NULL
- && strncmp (S_GET_NAME (removed), "$xrv", 4) == 0
- ? S_GET_NAME (removed) + 2 : NULL;
+ /* Search and find the previous $x+isa which in the same section.
+ We added $x+isa at the start of all sections, so should find at
+ least that one. */
+ const char *str = NULL;
+ symbolS *p = symbol_previous (symbol);
+ for (; p != NULL; p = symbol_previous (p))
+ {
+ if (now_seg == S_GET_SEGMENT (p)
+ && S_GET_NAME (p)
+ && strncmp (S_GET_NAME (p), "$xrv", 4) == 0
+ && S_GET_VALUE (p) <= S_GET_VALUE (symbol))
+ {
+ str = S_GET_NAME (p) + 2;
+ break;
+ }
+ }
make_mapping_symbol (MAP_INSN, frag->fr_fix + 1, frag, str,
false/* odd_data_padding */);
}
@@ -607,7 +615,6 @@ riscv_mapping_state (enum riscv_seg_mstate to_state,
{
enum riscv_seg_mstate from_state =
seg_info (now_seg)->tc_segment_info_data.map_state;
- bool reset_seg_arch_str = false;
if (!SEG_NORMAL (now_seg)
/* For now we only add the mapping symbols to text sections.
@@ -622,26 +629,22 @@ riscv_mapping_state (enum riscv_seg_mstate to_state,
symbolS *seg_arch_symbol =
seg_info (now_seg)->tc_segment_info_data.arch_map_symbol;
if (to_state == MAP_INSN && seg_arch_symbol == 0)
- {
- /* Always add $x+arch at the first instruction of section. */
- reset_seg_arch_str = true;
- }
+ /* The start of section. */
+ ;
else if (seg_arch_symbol != 0
&& to_state == MAP_INSN
&& !fr_align_code
&& strcmp (riscv_rps_as.subset_list->arch_str,
S_GET_NAME (seg_arch_symbol) + 2) != 0)
- {
- reset_seg_arch_str = true;
- }
+ /* Different architecture string. */
+ ;
else if (from_state == to_state)
return;
valueT value = (valueT) (frag_now_fix () - max_chars);
seg_info (now_seg)->tc_segment_info_data.map_state = to_state;
seg_info (now_seg)->tc_segment_info_data.last_insn16 = false;
- const char *arch_str = reset_seg_arch_str
- ? riscv_rps_as.subset_list->arch_str : NULL;
+ const char *arch_str = riscv_rps_as.subset_list->arch_str;
make_mapping_symbol (to_state, value, frag_now, arch_str,
false/* odd_data_padding */);
}
diff --git a/gas/testsuite/gas/riscv/mapping-symbols.d b/gas/testsuite/gas/riscv/mapping-symbols.d
index 057454bf991..ab1d4700e5f 100644
--- a/gas/testsuite/gas/riscv/mapping-symbols.d
+++ b/gas/testsuite/gas/riscv/mapping-symbols.d
@@ -20,14 +20,13 @@ SYMBOL TABLE:
0+00 l d .text.odd.align.start.insn 0+00 .text.odd.align.start.insn
0+00 l .text.odd.align.start.insn 0+00 \$xrv32i2p1_c2p0
0+02 l .text.odd.align.start.insn 0+00 \$d
-0+08 l .text.odd.align.start.insn 0+00 \$xrv32i2p1
0+00 l d .text.odd.align.start.data 0+00 .text.odd.align.start.data
0+00 l .text.odd.align.start.data 0+00 \$d
0+00 l d .text.zero.fill.first 0+00 .text.zero.fill.first
0+00 l .text.zero.fill.first 0+00 \$xrv32i2p1_c2p0
0+00 l d .text.zero.fill.last 0+00 .text.zero.fill.last
0+00 l .text.zero.fill.last 0+00 \$xrv32i2p1_c2p0
-0+02 l .text.zero.fill.last 0+00 \$x
+0+02 l .text.zero.fill.last 0+00 \$xrv32i2p1_c2p0
0+00 l d .text.zero.fill.align.A 0+00 .text.zero.fill.align.A
0+00 l .text.zero.fill.align.A 0+00 \$xrv32i2p1_c2p0
0+00 l d .text.zero.fill.align.B 0+00 .text.zero.fill.align.B
@@ -42,9 +41,9 @@ SYMBOL TABLE:
0+00 l d .text.relax.align 0+00 .text.relax.align
0+00 l .text.relax.align 0+00 \$xrv32i2p1_c2p0
0+08 l .text.relax.align 0+00 \$xrv32i2p1
-0+0a l .text.section.padding 0+00 \$x
+0+0a l .text.section.padding 0+00 \$xrv32i2p1_c2p0
0+03 l .text.odd.align.start.insn 0+00 \$d
-0+04 l .text.odd.align.start.insn 0+00 \$x
+0+04 l .text.odd.align.start.insn 0+00 \$xrv32i2p1
0+01 l .text.odd.align.start.data 0+00 \$d
0+02 l .text.odd.align.start.data 0+00 \$xrv32i2p1_c2p0
0+00 l d .riscv.attributes 0+00 .riscv.attributes
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