[binutils-gdb] opcodes/riscv: Hide '.L0 ' fake symbols
Andrew Burgess
aburgess@sourceware.org
Thu Dec 6 09:42:00 GMT 2018
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=884b49e3a91504b9c5528343823d67f4419b73bb
commit 884b49e3a91504b9c5528343823d67f4419b73bb
Author: Andrew Burgess <andrew.burgess@embecosm.com>
Date: Mon Dec 3 14:46:18 2018 +0000
opcodes/riscv: Hide '.L0 ' fake symbols
The RISC-V assembler generates fake labels with the name '.L0 ' as
part of the debug information (see
gas/config/tc-riscv.h:FAKE_LABEL_NAME).
The problem is that currently, when disassembling an object file, the
output looks like this (this is an example from the GDB testsuite, but
is pretty representative of anything with debug information):
000000000000001e <main>:
1e: 7179 addi sp,sp,-48
20: f406 sd ra,40(sp)
22: f022 sd s0,32(sp)
24: 1800 addi s0,sp,48
0000000000000026 <.L0 >:
26: 87aa mv a5,a0
28: feb43023 sd a1,-32(s0)
2c: fcc43c23 sd a2,-40(s0)
30: fef42623 sw a5,-20(s0)
0000000000000034 <.L0 >:
34: fec42783 lw a5,-20(s0)
38: 0007871b sext.w a4,a5
3c: 678d lui a5,0x3
3e: 03978793 addi a5,a5,57 # 3039 <.LASF30+0x2a9d>
42: 02f71463 bne a4,a5,6a <.L0 >
0000000000000046 <.L0 >:
46: 000007b7 lui a5,0x0
4a: 0007b783 ld a5,0(a5) # 0 <need_malloc>
4e: 6f9c ld a5,24(a5)
0000000000000050 <.L0 >:
50: 86be mv a3,a5
52: 466d li a2,27
54: 4585 li a1,1
56: 000007b7 lui a5,0x0
5a: 00078513 mv a0,a5
5e: 00000097 auipc ra,0x0
62: 000080e7 jalr ra # 5e <.L0 +0xe>
0000000000000066 <.L0 >:
66: 4785 li a5,1
68: a869 j 102 <.L0 >
000000000000006a <.L0 >:
6a: 000007b7 lui a5,0x0
6e: 00078513 mv a0,a5
72: 00000097 auipc ra,0x0
76: 000080e7 jalr ra # 72 <.L0 +0x8>
The frequent repeated '.L0 ' labels are pointless, as they are
non-unique there's no way to match a use of '.L0 ' to its appearence
in the output, so we'd be better off just not printing it at all.
That's what this patch does by defining a 'symbol_is_valid' method for
RISC-V. With this commit, the same disassembly now looks like this:
000000000000001e <main>:
1e: 7179 addi sp,sp,-48
20: f406 sd ra,40(sp)
22: f022 sd s0,32(sp)
24: 1800 addi s0,sp,48
26: 87aa mv a5,a0
28: feb43023 sd a1,-32(s0)
2c: fcc43c23 sd a2,-40(s0)
30: fef42623 sw a5,-20(s0)
34: fec42783 lw a5,-20(s0)
38: 0007871b sext.w a4,a5
3c: 678d lui a5,0x3
3e: 03978793 addi a5,a5,57 # 3039 <.LASF30+0x2a9d>
42: 02f71463 bne a4,a5,6a <.L4>
46: 000007b7 lui a5,0x0
4a: 0007b783 ld a5,0(a5) # 0 <need_malloc>
4e: 6f9c ld a5,24(a5)
50: 86be mv a3,a5
52: 466d li a2,27
54: 4585 li a1,1
56: 000007b7 lui a5,0x0
5a: 00078513 mv a0,a5
5e: 00000097 auipc ra,0x0
62: 000080e7 jalr ra # 5e <main+0x40>
66: 4785 li a5,1
68: a869 j 102 <.L5>
000000000000006a <.L4>:
6a: 000007b7 lui a5,0x0
6e: 00078513 mv a0,a5
72: 00000097 auipc ra,0x0
76: 000080e7 jalr ra # 72 <.L4+0x8>
In order to share the fake label between the assembler and the
libopcodes library, I've added some new defines RISCV_FAKE_LABEL_NAME
and RISCV_FAKE_LABEL_CHAR in include/opcode/riscv.h. I could have
just moved FAKE_LABEL_NAME to the include file, however, I thnk this
would be confusing, someone working on the assembler would likely not
expect to find FAKE_LABEL_NAME defined outside of the assembler source
tree. By introducing the RISCV_FAKE_LABEL_* defines I can leave the
assembler standard FAKE_LABEL_ defines in the assembler source, but
still share the RISCV_FAKE_LABEL_* with libopcodes.
gas/ChangeLog:
* config/tc-riscv.h (FAKE_LABEL_NAME): Define as
RISCV_FAKE_LABEL_NAME.
(FAKE_LABEL_CHAR): Define as RISCV_FAKE_LABEL_CHAR.
include/ChangeLog:
* dis-asm.h (riscv_symbol_is_valid): Declare.
* opcode/riscv.h (RISCV_FAKE_LABEL_NAME): Define.
(RISCV_FAKE_LABEL_CHAR): Define.
opcodes/ChangeLog:
* disassembler.c (disassemble_init_for_target): Add RISC-V
initialisation.
* riscv-dis.c (riscv_symbol_is_valid): New function.
Diff:
---
gas/ChangeLog | 6 ++++++
gas/config/tc-riscv.h | 4 ++--
include/ChangeLog | 6 ++++++
include/dis-asm.h | 1 +
include/opcode/riscv.h | 6 ++++++
opcodes/ChangeLog | 6 ++++++
opcodes/disassemble.c | 5 +++++
opcodes/riscv-dis.c | 17 +++++++++++++++++
8 files changed, 49 insertions(+), 2 deletions(-)
diff --git a/gas/ChangeLog b/gas/ChangeLog
index 73cadc7..a4e0767 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,9 @@
+2018-12-06 Andrew Burgess <andrew.burgess@embecosm.com>
+
+ * config/tc-riscv.h (FAKE_LABEL_NAME): Define as
+ RISCV_FAKE_LABEL_NAME.
+ (FAKE_LABEL_CHAR): Define as RISCV_FAKE_LABEL_CHAR.
+
2018-12-05 Sam Tebbs <sam.tebbs@arm.com>
* dw2gencfi.c (struct cie_entry): Add tc_cie_entry_extras invocation.
diff --git a/gas/config/tc-riscv.h b/gas/config/tc-riscv.h
index 5e59740..41a18be 100644
--- a/gas/config/tc-riscv.h
+++ b/gas/config/tc-riscv.h
@@ -38,10 +38,10 @@ struct expressionS;
/* Symbols named FAKE_LABEL_NAME are emitted when generating DWARF, so make
sure FAKE_LABEL_NAME is printable. It still must be distinct from any
real label name. So, append a space, which other labels can't contain. */
-#define FAKE_LABEL_NAME ".L0 "
+#define FAKE_LABEL_NAME RISCV_FAKE_LABEL_NAME
/* Changing the special character in FAKE_LABEL_NAME requires changing
FAKE_LABEL_CHAR too. */
-#define FAKE_LABEL_CHAR ' '
+#define FAKE_LABEL_CHAR RISCV_FAKE_LABEL_CHAR
#define md_relax_frag(segment, fragp, stretch) \
riscv_relax_frag (segment, fragp, stretch)
diff --git a/include/ChangeLog b/include/ChangeLog
index 7375bac..b3fd56b 100644
--- a/include/ChangeLog
+++ b/include/ChangeLog
@@ -1,3 +1,9 @@
+2018-12-06 Andrew Burgess <andrew.burgess@embecosm.com>
+
+ * dis-asm.h (riscv_symbol_is_valid): Declare.
+ * opcode/riscv.h (RISCV_FAKE_LABEL_NAME): Define.
+ (RISCV_FAKE_LABEL_CHAR): Define.
+
2018-12-03 Kito Cheng <kito@andestech.com>
* opcode/riscv.h (riscv_opcode): Change type of xlen_requirement to
diff --git a/include/dis-asm.h b/include/dis-asm.h
index 8462795..6a55f3c 100644
--- a/include/dis-asm.h
+++ b/include/dis-asm.h
@@ -302,6 +302,7 @@ extern void print_wasm32_disassembler_options (FILE *);
extern bfd_boolean aarch64_symbol_is_valid (asymbol *, struct disassemble_info *);
extern bfd_boolean arm_symbol_is_valid (asymbol *, struct disassemble_info *);
extern bfd_boolean csky_symbol_is_valid (asymbol *, struct disassemble_info *);
+extern bfd_boolean riscv_symbol_is_valid (asymbol *, struct disassemble_info *);
extern void disassemble_init_powerpc (struct disassemble_info *);
extern void disassemble_init_s390 (struct disassemble_info *);
extern void disassemble_init_wasm32 (struct disassemble_info *);
diff --git a/include/opcode/riscv.h b/include/opcode/riscv.h
index 12cb4ca..d57f45b 100644
--- a/include/opcode/riscv.h
+++ b/include/opcode/riscv.h
@@ -270,6 +270,12 @@ static const char * const riscv_pred_succ[16] =
#define NGPR 32
#define NFPR 32
+/* These fake label defines are use by both the assembler, and
+ libopcodes. The assembler uses this when it needs to generate a fake
+ label, and libopcodes uses it to hide the fake labels in its output. */
+#define RISCV_FAKE_LABEL_NAME ".L0 "
+#define RISCV_FAKE_LABEL_CHAR ' '
+
/* Replace bits MASK << SHIFT of STRUCT with the equivalent bits in
VALUE << SHIFT. VALUE is evaluated exactly once. */
#define INSERT_BITS(STRUCT, VALUE, MASK, SHIFT) \
diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index b04cf0e..753be9f 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,9 @@
+2018-12-06 Andrew Burgess <andrew.burgess@embecosm.com>
+
+ * disassembler.c (disassemble_init_for_target): Add RISC-V
+ initialisation.
+ * riscv-dis.c (riscv_symbol_is_valid): New function.
+
2018-12-03 Kito Cheng <kito@andestech.com>
* riscv-opc.c: Change the type of xlen, because type of
diff --git a/opcodes/disassemble.c b/opcodes/disassemble.c
index 750d76a..7370bd1 100644
--- a/opcodes/disassemble.c
+++ b/opcodes/disassemble.c
@@ -656,6 +656,11 @@ disassemble_init_for_target (struct disassemble_info * info)
disassemble_init_powerpc (info);
break;
#endif
+#ifdef ARCH_riscv
+ case bfd_arch_riscv:
+ info->symbol_is_valid = riscv_symbol_is_valid;
+ break;
+#endif
#ifdef ARCH_wasm32
case bfd_arch_wasm32:
disassemble_init_wasm32 (info);
diff --git a/opcodes/riscv-dis.c b/opcodes/riscv-dis.c
index 9790820..f1bbfdb 100644
--- a/opcodes/riscv-dis.c
+++ b/opcodes/riscv-dis.c
@@ -518,6 +518,23 @@ print_insn_riscv (bfd_vma memaddr, struct disassemble_info *info)
return riscv_disassemble_insn (memaddr, insn, info);
}
+/* Prevent use of the fake labels that are generated as part of the DWARF
+ and for relaxable relocations in the assembler. */
+
+bfd_boolean
+riscv_symbol_is_valid (asymbol * sym,
+ struct disassemble_info * info ATTRIBUTE_UNUSED)
+{
+ const char * name;
+
+ if (sym == NULL)
+ return FALSE;
+
+ name = bfd_asymbol_name (sym);
+
+ return (strcmp (name, RISCV_FAKE_LABEL_NAME) != 0);
+}
+
void
print_riscv_disassembler_options (FILE *stream)
{
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