[lldb][LoongArch] Fix the incorrect floating-point register dwarf number #120391

wangleiat · 2024-12-18T09:22:02Z

According to the documentation described at
https://github.com/loongson/la-abi-specs/blob/release/ladwarf.adoc, the
dwarf numbers for floating-point registers range from 32 to 63.

An incorrect dwarf number will prevent the register values from being
properly restored during unwinding.

This test reflects this problem:

loongson@linux:~$ cat test.c

void foo() {
  asm volatile ("movgr2fr.d $fs2, $ra":::"$fs2");
}
int main() {
  asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2");
  foo();
  return 0;
}

loongson@linux:~$ clang -g test.c  -o test

Without this patch:

loongson@linux:~$ ./_build/bin/lldb ./t
(lldb) target create "./t"
Current executable set to
'/home/loongson/llvm-project/_build_lldb/t' (loongarch64).
(lldb) b foo
Breakpoint 1: where = t`foo + 20 at test.c:4:1, address =
0x0000000000000714
(lldb) r
Process 2455626 launched: '/home/loongson/llvm-project/_build_lldb/t' (loongarch64)
Process 2455626 stopped
* thread #1, name = 't', stop reason = breakpoint 1.1
    frame #0: 0x0000555555554714 t`foo at test.c:4:1
   1    #include <stdio.h>
   2
   3    void foo() {
-> 4    asm volatile ("movgr2fr.d $fs2, $ra":::"$fs2");
   5    }
   6    int main() {
   7    asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2");
(lldb) si
Process 2455626 stopped
* thread #1, name = 't', stop reason = instruction step into
    frame #0: 0x0000555555554718 t`foo at test.c:4:1
   1    #include <stdio.h>
   2
   3    void foo() {
-> 4    asm volatile ("movgr2fr.d $fs2, $ra":::"$fs2");
   5    }
   6    int main() {
   7    asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2");
(lldb) f 1
frame #1: 0x0000555555554768 t`main at test.c:8:1
   5    }
   6    int main() {
   7    asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2");
-> 8    foo();
   9    return 0;
   10   }
(lldb) register read -a
General Purpose Registers:
        r1 = 0x0000555555554768  t`main + 40 at test.c:8:1
        r3 = 0x00007ffffffef780
       r22 = 0x00007ffffffef7b0
       r23 = 0x00007ffffffef918
       r24 = 0x0000000000000001
       r25 = 0x0000000000000000
       r26 = 0x000055555555be08  t`__do_global_dtors_aux_fini_array_entry
       r27 = 0x0000555555554740  t`main at test.c:6
       r28 = 0x00007ffffffef928
       r29 = 0x00007ffff7febc88  ld-linux-loongarch-lp64d.so.1`_rtld_global_ro
       r30 = 0x000055555555be08  t`__do_global_dtors_aux_fini_array_entry
        pc = 0x0000555555554768  t`main + 40 at test.c:8:1
33 registers were unavailable.

Floating Point Registers:
       f13 = 0x00007ffffffef780 !!!!! wrong register
       f24 = 0xffffffffffffffff
       f25 = 0xffffffffffffffff
       f26 = 0x0000555555554768  t`main + 40 at test.c:8:1
       f27 = 0xffffffffffffffff
       f28 = 0xffffffffffffffff
       f29 = 0xffffffffffffffff
       f30 = 0xffffffffffffffff
       f31 = 0xffffffffffffffff
32 registers were unavailable.

With this patch:

The previous operations are the same.
(lldb) register read -a
General Purpose Registers:
        r1 = 0x0000555555554768  t`main + 40 at test.c:8:1
        r3 = 0x00007ffffffef780
       r22 = 0x00007ffffffef7b0
       r23 = 0x00007ffffffef918
       r24 = 0x0000000000000001
       r25 = 0x0000000000000000
       r26 = 0x000055555555be08  t`__do_global_dtors_aux_fini_array_entry
       r27 = 0x0000555555554740  t`main at test.c:6
       r28 = 0x00007ffffffef928
       r29 = 0x00007ffff7febc88  ld-linux-loongarch-lp64d.so.1`_rtld_global_ro
       r30 = 0x000055555555be08  t`__do_global_dtors_aux_fini_array_entry
        pc = 0x0000555555554768  t`main + 40 at test.c:8:1
33 registers were unavailable.

Floating Point Registers:
       f24 = 0xffffffffffffffff
       f25 = 0xffffffffffffffff
       f26 = 0x00007ffffffef780
       f27 = 0xffffffffffffffff
       f28 = 0xffffffffffffffff
       f29 = 0xffffffffffffffff
       f30 = 0xffffffffffffffff
       f31 = 0xffffffffffffffff
33 registers were unavailable.

Created using spr 1.3.5-bogner

llvmbot · 2024-12-18T09:22:41Z

@llvm/pr-subscribers-lldb

Author: wanglei (wangleiat)

Changes

According to the documentation described at
https://github.com/loongson/la-abi-specs/blob/release/ladwarf.adoc, the
dwarf numbers for floating-point registers range from 32 to 63.

An incorrect dwarf number will prevent the register values from being
properly restored during unwinding.

This test reflects this problem:

loongson@<!-- -->linux:~$ cat test.c

void foo() {
  asm volatile ("movgr2fr.d $fs2, $ra":::"$fs2");
}
int main() {
  asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2");
  foo();
  return 0;
}

loongson@<!-- -->linux:~$ clang -g test.c  -o test

Without this patch:

loongson@<!-- -->linux:~$ ./_build/bin/lldb ./t
(lldb) target create "./t"
Current executable set to
'/home/loongson/llvm-project/_build_lldb/t' (loongarch64).
(lldb) b foo
Breakpoint 1: where = t`foo + 20 at test.c:4:1, address =
0x0000000000000714
(lldb) r
Process 2455626 launched: '/home/loongson/llvm-project/_build_lldb/t' (loongarch64)
Process 2455626 stopped
* thread #<!-- -->1, name = 't', stop reason = breakpoint 1.1
    frame #<!-- -->0: 0x0000555555554714 t`foo at test.c:4:1
   1    #include &lt;stdio.h&gt;
   2
   3    void foo() {
-&gt; 4    asm volatile ("movgr2fr.d $fs2, $ra":::"$fs2");
   5    }
   6    int main() {
   7    asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2");
(lldb) si
Process 2455626 stopped
* thread #<!-- -->1, name = 't', stop reason = instruction step into
    frame #<!-- -->0: 0x0000555555554718 t`foo at test.c:4:1
   1    #include &lt;stdio.h&gt;
   2
   3    void foo() {
-&gt; 4    asm volatile ("movgr2fr.d $fs2, $ra":::"$fs2");
   5    }
   6    int main() {
   7    asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2");
(lldb) f 1
frame #<!-- -->1: 0x0000555555554768 t`main at test.c:8:1
   5    }
   6    int main() {
   7    asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2");
-&gt; 8    foo();
   9    return 0;
   10   }
(lldb) register read -a
General Purpose Registers:
        r1 = 0x0000555555554768  t`main + 40 at test.c:8:1
        r3 = 0x00007ffffffef780
       r22 = 0x00007ffffffef7b0
       r23 = 0x00007ffffffef918
       r24 = 0x0000000000000001
       r25 = 0x0000000000000000
       r26 = 0x000055555555be08  t`__do_global_dtors_aux_fini_array_entry
       r27 = 0x0000555555554740  t`main at test.c:6
       r28 = 0x00007ffffffef928
       r29 = 0x00007ffff7febc88  ld-linux-loongarch-lp64d.so.1`_rtld_global_ro
       r30 = 0x000055555555be08  t`__do_global_dtors_aux_fini_array_entry
        pc = 0x0000555555554768  t`main + 40 at test.c:8:1
33 registers were unavailable.

Floating Point Registers:
       f13 = 0x00007ffffffef780 !!!!! wrong register
       f24 = 0xffffffffffffffff
       f25 = 0xffffffffffffffff
       f26 = 0x0000555555554768  t`main + 40 at test.c:8:1
       f27 = 0xffffffffffffffff
       f28 = 0xffffffffffffffff
       f29 = 0xffffffffffffffff
       f30 = 0xffffffffffffffff
       f31 = 0xffffffffffffffff
32 registers were unavailable.

With this patch:

The previous operations are the same.
(lldb) register read -a
General Purpose Registers:
        r1 = 0x0000555555554768  t`main + 40 at test.c:8:1
        r3 = 0x00007ffffffef780
       r22 = 0x00007ffffffef7b0
       r23 = 0x00007ffffffef918
       r24 = 0x0000000000000001
       r25 = 0x0000000000000000
       r26 = 0x000055555555be08  t`__do_global_dtors_aux_fini_array_entry
       r27 = 0x0000555555554740  t`main at test.c:6
       r28 = 0x00007ffffffef928
       r29 = 0x00007ffff7febc88  ld-linux-loongarch-lp64d.so.1`_rtld_global_ro
       r30 = 0x000055555555be08  t`__do_global_dtors_aux_fini_array_entry
        pc = 0x0000555555554768  t`main + 40 at test.c:8:1
33 registers were unavailable.

Floating Point Registers:
       f24 = 0xffffffffffffffff
       f25 = 0xffffffffffffffff
       f26 = 0x00007ffffffef780
       f27 = 0xffffffffffffffff
       f28 = 0xffffffffffffffff
       f29 = 0xffffffffffffffff
       f30 = 0xffffffffffffffff
       f31 = 0xffffffffffffffff
33 registers were unavailable.

Full diff: https://github.com/llvm/llvm-project/pull/120391.diff

1 Files Affected:

(modified) lldb/source/Utility/LoongArch_DWARF_Registers.h (+19-17)

diff --git a/lldb/source/Utility/LoongArch_DWARF_Registers.h b/lldb/source/Utility/LoongArch_DWARF_Registers.h
index 34e40a066051ee..596806348ee245 100644
--- a/lldb/source/Utility/LoongArch_DWARF_Registers.h
+++ b/lldb/source/Utility/LoongArch_DWARF_Registers.h
@@ -47,22 +47,7 @@ enum {
   dwarf_gpr_r30,
   dwarf_gpr_r31 = 31,
 
-  dwarf_gpr_orig_a0,
-  dwarf_gpr_pc,
-  dwarf_gpr_badv,
-
-  dwarf_gpr_reserved0 = 35,
-  dwarf_gpr_reserved1,
-  dwarf_gpr_reserved2,
-  dwarf_gpr_reserved3,
-  dwarf_gpr_reserved4,
-  dwarf_gpr_reserved5,
-  dwarf_gpr_reserved6,
-  dwarf_gpr_reserved7,
-  dwarf_gpr_reserved8,
-  dwarf_gpr_reserved9,
-
-  dwarf_fpr_f0 = 45,
+  dwarf_fpr_f0 = 32,
   dwarf_fpr_f1,
   dwarf_fpr_f2,
   dwarf_fpr_f3,
@@ -93,7 +78,7 @@ enum {
   dwarf_fpr_f28,
   dwarf_fpr_f29,
   dwarf_fpr_f30,
-  dwarf_fpr_f31 = 76,
+  dwarf_fpr_f31 = 63,
 
   dwarf_fpr_fcc0,
   dwarf_fpr_fcc1,
@@ -170,6 +155,23 @@ enum {
   dwarf_fpr_fs5 = dwarf_fpr_f29,
   dwarf_fpr_fs6 = dwarf_fpr_f30,
   dwarf_fpr_fs7 = dwarf_fpr_f31,
+
+  // mock pc regnum
+  dwarf_gpr_pc = 57005,
+
+  // fake registers are only used to define `RegisterInfo`
+  dwarf_gpr_orig_a0,
+  dwarf_gpr_badv,
+  dwarf_gpr_reserved0,
+  dwarf_gpr_reserved1,
+  dwarf_gpr_reserved2,
+  dwarf_gpr_reserved3,
+  dwarf_gpr_reserved4,
+  dwarf_gpr_reserved5,
+  dwarf_gpr_reserved6,
+  dwarf_gpr_reserved7,
+  dwarf_gpr_reserved8,
+  dwarf_gpr_reserved9,
 };
 
 } // namespace loongarch_dwarf

…r dwarf number According to the documentation described at https://github.com/loongson/la-abi-specs/blob/release/ladwarf.adoc, the dwarf numbers for floating-point registers range from 32 to 63. An incorrect dwarf number will prevent the register values from being properly restored during unwinding. This test reflects this problem: ``` loongson@linux:~$ cat test.c void foo() { asm volatile ("movgr2fr.d $fs2, $ra":::"$fs2"); } int main() { asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2"); foo(); return 0; } loongson@linux:~$ clang -g test.c -o test ``` Without this patch: ``` loongson@linux:~$ ./_build/bin/lldb ./t (lldb) target create "./t" Current executable set to '/home/loongson/llvm-project/_build_lldb/t' (loongarch64). (lldb) b foo Breakpoint 1: where = t`foo + 20 at test.c:4:1, address = 0x0000000000000714 (lldb) r Process 2455626 launched: '/home/loongson/llvm-project/_build_lldb/t' (loongarch64) Process 2455626 stopped * thread #1, name = 't', stop reason = breakpoint 1.1 frame #0: 0x0000555555554714 t`foo at test.c:4:1 1 #include <stdio.h> 2 3 void foo() { -> 4 asm volatile ("movgr2fr.d $fs2, $ra":::"$fs2"); 5 } 6 int main() { 7 asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2"); (lldb) si Process 2455626 stopped * thread #1, name = 't', stop reason = instruction step into frame #0: 0x0000555555554718 t`foo at test.c:4:1 1 #include <stdio.h> 2 3 void foo() { -> 4 asm volatile ("movgr2fr.d $fs2, $ra":::"$fs2"); 5 } 6 int main() { 7 asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2"); (lldb) f 1 frame #1: 0x0000555555554768 t`main at test.c:8:1 5 } 6 int main() { 7 asm volatile ("movgr2fr.d $fs2, $sp":::"$fs2"); -> 8 foo(); 9 return 0; 10 } (lldb) register read -a General Purpose Registers: r1 = 0x0000555555554768 t`main + 40 at test.c:8:1 r3 = 0x00007ffffffef780 r22 = 0x00007ffffffef7b0 r23 = 0x00007ffffffef918 r24 = 0x0000000000000001 r25 = 0x0000000000000000 r26 = 0x000055555555be08 t`__do_global_dtors_aux_fini_array_entry r27 = 0x0000555555554740 t`main at test.c:6 r28 = 0x00007ffffffef928 r29 = 0x00007ffff7febc88 ld-linux-loongarch-lp64d.so.1`_rtld_global_ro r30 = 0x000055555555be08 t`__do_global_dtors_aux_fini_array_entry pc = 0x0000555555554768 t`main + 40 at test.c:8:1 33 registers were unavailable. Floating Point Registers: f13 = 0x00007ffffffef780 !!!!! wrong register f24 = 0xffffffffffffffff f25 = 0xffffffffffffffff f26 = 0x0000555555554768 t`main + 40 at test.c:8:1 f27 = 0xffffffffffffffff f28 = 0xffffffffffffffff f29 = 0xffffffffffffffff f30 = 0xffffffffffffffff f31 = 0xffffffffffffffff 32 registers were unavailable. ``` With this patch: ``` The previous operations are the same. (lldb) register read -a General Purpose Registers: r1 = 0x0000555555554768 t`main + 40 at test.c:8:1 r3 = 0x00007ffffffef780 r22 = 0x00007ffffffef7b0 r23 = 0x00007ffffffef918 r24 = 0x0000000000000001 r25 = 0x0000000000000000 r26 = 0x000055555555be08 t`__do_global_dtors_aux_fini_array_entry r27 = 0x0000555555554740 t`main at test.c:6 r28 = 0x00007ffffffef928 r29 = 0x00007ffff7febc88 ld-linux-loongarch-lp64d.so.1`_rtld_global_ro r30 = 0x000055555555be08 t`__do_global_dtors_aux_fini_array_entry pc = 0x0000555555554768 t`main + 40 at test.c:8:1 33 registers were unavailable. Floating Point Registers: f24 = 0xffffffffffffffff f25 = 0xffffffffffffffff f26 = 0x00007ffffffef780 f27 = 0xffffffffffffffff f28 = 0xffffffffffffffff f29 = 0xffffffffffffffff f30 = 0xffffffffffffffff f31 = 0xffffffffffffffff 33 registers were unavailable. ``` Reviewed By: SixWeining Pull Request: llvm/llvm-project#120391

[𝘀𝗽𝗿] initial version

2aa4bcf

Created using spr 1.3.5-bogner

wangleiat requested a review from JDevlieghere as a code owner December 18, 2024 09:22

llvmbot added the lldb label Dec 18, 2024

wangleiat requested a review from SixWeining December 18, 2024 09:22

SixWeining approved these changes Dec 19, 2024

View reviewed changes

wangleiat merged commit eb1b9fc into main Dec 20, 2024
9 checks passed

wangleiat deleted the users/wangleiat/spr/lldbloongarch-fix-the-incorrect-floating-point-register-dwarf-number branch December 20, 2024 01:03

SixWeining mentioned this pull request Dec 20, 2024

LLDB LoongArch support #112693

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[lldb][LoongArch] Fix the incorrect floating-point register dwarf number #120391

[lldb][LoongArch] Fix the incorrect floating-point register dwarf number #120391

wangleiat commented Dec 18, 2024

llvmbot commented Dec 18, 2024

[lldb][LoongArch] Fix the incorrect floating-point register dwarf number #120391

[lldb][LoongArch] Fix the incorrect floating-point register dwarf number #120391

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wangleiat commented Dec 18, 2024

llvmbot commented Dec 18, 2024