[binutils-gdb] x86/disasm: rework comment handling
Jan Beulich
jbeulich@sourceware.org
Fri May 22 06:50:40 GMT 2026
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=aeced13ee0cd570d78cb37ab1f9bba840958515a
commit aeced13ee0cd570d78cb37ab1f9bba840958515a
Author: Jan Beulich <jbeulich@suse.com>
Date: Fri May 22 08:49:12 2026 +0200
x86/disasm: rework comment handling
Model this after operand handling, such that comments can be emitted in
the same order as operands. %rip-relative address comments remain
separate for now. While there correct style for the symbols associated
with immediates: These aren't "comment starts", but symbol names.
Diff:
---
.../testsuite/binutils-all/x86-64/comments-intel.d | 14 ++++++
binutils/testsuite/binutils-all/x86-64/comments.d | 14 ++++++
binutils/testsuite/binutils-all/x86-64/comments.s | 9 ++++
opcodes/i386-dis.c | 52 +++++++++++++++-------
4 files changed, 74 insertions(+), 15 deletions(-)
diff --git a/binutils/testsuite/binutils-all/x86-64/comments-intel.d b/binutils/testsuite/binutils-all/x86-64/comments-intel.d
new file mode 100644
index 00000000000..3ebdafd6703
--- /dev/null
+++ b/binutils/testsuite/binutils-all/x86-64/comments-intel.d
@@ -0,0 +1,14 @@
+#name: disassembly comments (Intel)
+#source: comments.s
+#ld:
+#objdump: -dwMannotate,intel
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+[0-9a-f]+ <_start>:
+[ ]*[0-9a-f]+: 48 c7 05 [0-9a-f ]+ mov QWORD PTR \[rip\+0x[0-9a-f]+\],0x[0-9a-f]+ +# [0-9a-f]+ <fptr>, \[_start\]
+[ ]*[0-9a-f]+: 31 c0 xor eax,eax
+[ ]*[0-9a-f]+: c3 ret
diff --git a/binutils/testsuite/binutils-all/x86-64/comments.d b/binutils/testsuite/binutils-all/x86-64/comments.d
new file mode 100644
index 00000000000..15d35853411
--- /dev/null
+++ b/binutils/testsuite/binutils-all/x86-64/comments.d
@@ -0,0 +1,14 @@
+#name: disassembly comments (AT&T)
+#ld:
+#objdump: -dwMannotate,att
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+[0-9a-f]+ <_start>:
+[ ]*[0-9a-f]+: 48 c7 05 [0-9a-f ]+ movq \$0x[0-9a-f]+,0x[0-9a-f]+\(%rip\) +# \[_start\], [0-9a-f]+ <fptr>
+[ ]*[0-9a-f]+: 31 c0 xor %eax,%eax
+[ ]*[0-9a-f]+: c3 ret
+#pass
diff --git a/binutils/testsuite/binutils-all/x86-64/comments.s b/binutils/testsuite/binutils-all/x86-64/comments.s
new file mode 100644
index 00000000000..443dea7e3fa
--- /dev/null
+++ b/binutils/testsuite/binutils-all/x86-64/comments.s
@@ -0,0 +1,9 @@
+ .text
+ .global _start
+_start:
+ movq $_start, fptr(%rip)
+ xor %eax, %eax
+ ret
+
+ .data
+fptr: .quad -1
diff --git a/opcodes/i386-dis.c b/opcodes/i386-dis.c
index ad0593cedd7..1faf1fa7785 100644
--- a/opcodes/i386-dis.c
+++ b/opcodes/i386-dis.c
@@ -179,8 +179,7 @@ struct instr_info
char obuf[MAX_OPERAND_BUFFER_SIZE];
char *obufp;
- char cbuf[COMMENT_BUFFER_SIZE];
- char * cbufp;
+ char *cbufp;
char *mnemonicendp;
const uint8_t *start_codep;
uint8_t *codep;
@@ -258,6 +257,7 @@ struct instr_info
signed char op_index[MAX_OPERANDS];
bool op_riprel[MAX_OPERANDS];
char *op_out[MAX_OPERANDS];
+ char *cm_out[MAX_OPERANDS];
bfd_vma op_address[MAX_OPERANDS];
bfd_vma start_pc;
@@ -9749,7 +9749,6 @@ print_insn (bfd_vma pc, disassemble_info *info, int intel_syntax)
.start_codep = priv.the_buffer,
.codep = priv.the_buffer,
.obufp = ins.obuf,
- .cbufp = ins.cbuf,
.last_lock_prefix = -1,
.last_repz_prefix = -1,
.last_repnz_prefix = -1,
@@ -9761,6 +9760,7 @@ print_insn (bfd_vma pc, disassemble_info *info, int intel_syntax)
.fwait_prefix = -1,
};
char op_out[MAX_OPERANDS][MAX_OPERAND_BUFFER_SIZE];
+ char cm_out[MAX_OPERANDS][COMMENT_BUFFER_SIZE];
priv.orig_sizeflag = AFLAG | DFLAG;
if ((info->mach & bfd_mach_i386_i386) != 0)
@@ -9874,6 +9874,8 @@ print_insn (bfd_vma pc, disassemble_info *info, int intel_syntax)
{
op_out[i][0] = 0;
ins.op_out[i] = op_out[i];
+ cm_out[i][0] = 0;
+ ins.cm_out[i] = cm_out[i];
}
sizeflag = priv.orig_sizeflag;
@@ -9992,6 +9994,7 @@ print_insn (bfd_vma pc, disassemble_info *info, int intel_syntax)
for (i = 0; i < MAX_OPERANDS; ++i)
{
ins.obufp = ins.op_out[i];
+ ins.cbufp = ins.cm_out[i];
ins.op_ad = MAX_OPERANDS - 1 - i;
if (dp->op[i].rtn
&& !dp->op[i].rtn (&ins, dp->op[i].bytemode, sizeflag))
@@ -10317,6 +10320,10 @@ print_insn (bfd_vma pc, disassemble_info *info, int intel_syntax)
riprel = ins.op_riprel[i];
ins.op_riprel[i] = ins.op_riprel[MAX_OPERANDS - 1 - i];
ins.op_riprel[MAX_OPERANDS - 1 - i] = riprel;
+
+ char *tmp = ins.cm_out[i];
+ ins.cm_out[i] = ins.cm_out[MAX_OPERANDS - 1 - i];
+ ins.cm_out[MAX_OPERANDS - 1 - i] = tmp;
}
}
else
@@ -10364,22 +10371,23 @@ print_insn (bfd_vma pc, disassemble_info *info, int intel_syntax)
needcomma = 1;
}
+ const char *sep = " # ";
for (i = 0; i < MAX_OPERANDS; i++)
if (ins.op_index[i] != -1 && ins.op_riprel[i])
{
- i386_dis_printf (info, dis_style_comment_start, " # ");
+ i386_dis_printf (info, dis_style_comment_start, sep);
+ sep = ", ";
(*info->print_address_func)
((bfd_vma)(ins.start_pc + (ins.codep - ins.start_codep)
+ ins.op_address[ins.op_index[i]]),
- info);
- break;
+ info);
+ }
+ else if (*ins.cm_out[i])
+ {
+ i386_dis_printf (info, dis_style_comment_start, sep);
+ sep = ", ";
+ i386_dis_printf (info, dis_style_symbol, "%s", ins.cm_out[i]);
}
- if (ins.cbufp != ins.cbuf)
- {
- if (i == MAX_OPERANDS)
- i386_dis_printf (info, dis_style_comment_start, " # ");
- i386_dis_printf (info, dis_style_comment_start, "%s", ins.cbuf);
- }
ret = ins.codep - priv.the_buffer;
out:
@@ -10760,6 +10768,7 @@ dofloat (instr_info *ins, int sizeflag)
putop (ins, float_mem[fp_indx], sizeflag);
ins->obufp = ins->op_out[0];
+ ins->cbufp = ins->cm_out[0];
ins->op_ad = 2;
return OP_E (ins, float_mem_mode[fp_indx], sizeflag);
}
@@ -10781,12 +10790,14 @@ dofloat (instr_info *ins, int sizeflag)
putop (ins, dp->name, sizeflag);
ins->obufp = ins->op_out[0];
+ ins->cbufp = ins->cm_out[0];
ins->op_ad = 2;
if (dp->op[0].rtn
&& !dp->op[0].rtn (ins, dp->op[0].bytemode, sizeflag))
return false;
ins->obufp = ins->op_out[1];
+ ins->cbufp = ins->cm_out[1];
ins->op_ad = 1;
if (dp->op[1].rtn
&& !dp->op[1].rtn (ins, dp->op[1].bytemode, sizeflag))
@@ -11588,16 +11599,19 @@ static void
cappend_with_style (instr_info *ins, const char *s,
enum disassembler_style style)
{
- if (ins->cbufp + strlen (s) + 4 >= ins->cbuf + COMMENT_BUFFER_SIZE)
+ size_t len = strlen (ins->cbufp);
+
+ if (len + !!len + strlen (s) + 4 >= COMMENT_BUFFER_SIZE)
return;
unsigned num = (unsigned) style;
+ if (len)
+ *ins->cbufp++ = ' ';
*ins->cbufp++ = STYLE_MARKER_CHAR;
*ins->cbufp++ = (num < 10 ? ('0' + num)
: ((num < 16) ? ('a' + (num - 10)) : '0'));
*ins->cbufp++ = STYLE_MARKER_CHAR;
- *ins->cbufp = '\0';
ins->cbufp = stpcpy (ins->cbufp, s);
}
@@ -11697,7 +11711,7 @@ oappend_immediate (instr_info *ins, bfd_vma imm)
char * annotation = NULL;
- if (asprintf (& annotation, " [%s]", sym->name) > 0)
+ if (asprintf (& annotation, "[%s]", sym->name) > 0)
{
/* Display the symbol associated with address 'imm'. */
cappend_with_style (ins, annotation, dis_style_symbol);
@@ -14255,6 +14269,10 @@ OP_VexW (instr_info *ins, int bytemode, int sizeflag)
ins->op_out[2] = ins->op_out[1];
ins->op_out[1] = tmp;
+
+ tmp = ins->cm_out[2];
+ ins->cm_out[2] = ins->cm_out[1];
+ ins->cm_out[1] = tmp;
}
return true;
}
@@ -14288,6 +14306,10 @@ OP_REG_VexI4 (instr_info *ins, int bytemode, int sizeflag ATTRIBUTE_UNUSED)
ins->op_out[3] = ins->op_out[2];
ins->op_out[2] = tmp;
+
+ tmp = ins->cm_out[2];
+ ins->cm_out[3] = ins->cm_out[2];
+ ins->cm_out[2] = tmp;
}
return true;
}
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