[AVR] Emit relocation record for local branch #145291

tomtor · 2025-06-23T08:42:34Z

Fix #133579 -mrelax issue

tomtor · 2025-06-23T08:51:40Z

@Patryk27 Please review

tomtor · 2025-06-23T09:17:42Z

The failing tests are related to the emitting of a relocation label. So this is expected, and we should adapt these tests if we agree on this PR.

benshi001

Thanks for your patch. But please learn some basic points before committing a functional change.

Unit tests are needed to show the impact by the functional change.
Run make check-all locally to ensure that no other unit tests are impacted.

Unfortunately this change leads the many failures, here is the log on my local CentOS.

Failed Tests (25):
  LLVM :: CodeGen/AVR/branch-relaxation-long-backward.ll
  LLVM :: CodeGen/AVR/branch-relaxation-long-forward.ll
  LLVM :: CodeGen/AVR/jmp.ll
  LLVM :: MC/AVR/inst-brbc.s
  LLVM :: MC/AVR/inst-brbs.s
  LLVM :: MC/AVR/inst-brcc.s
  LLVM :: MC/AVR/inst-brcs.s
  LLVM :: MC/AVR/inst-breq.s
  LLVM :: MC/AVR/inst-brge.s
  LLVM :: MC/AVR/inst-brhc.s
  LLVM :: MC/AVR/inst-brhs.s
  LLVM :: MC/AVR/inst-brid.s
  LLVM :: MC/AVR/inst-brie.s
  LLVM :: MC/AVR/inst-brlo.s
  LLVM :: MC/AVR/inst-brlt.s
  LLVM :: MC/AVR/inst-brmi.s
  LLVM :: MC/AVR/inst-brne.s
  LLVM :: MC/AVR/inst-brpl.s
  LLVM :: MC/AVR/inst-brsh.s
  LLVM :: MC/AVR/inst-brtc.s
  LLVM :: MC/AVR/inst-brts.s
  LLVM :: MC/AVR/inst-brvc.s
  LLVM :: MC/AVR/inst-brvs.s
  LLVM :: MC/AVR/inst-rcall.s
  LLVM :: MC/AVR/inst-rjmp.s


Testing Time: 89.38s

Total Discovered Tests: 66002
  Skipped          :   372 (0.56%)
  Unsupported      : 31014 (46.99%)
  Passed           : 34518 (52.30%)
  Expectedly Failed:    73 (0.11%)
  Failed           :    25 (0.04%)
make[3]: *** [test/CMakeFiles/check-llvm.dir/build.make:71: test/CMakeFiles/check-llvm] Error 1
make[2]: *** [CMakeFiles/Makefile2:199872: test/CMakeFiles/check-llvm.dir/all] Error 2
make[1]: *** [CMakeFiles/Makefile2:199879: test/CMakeFiles/check-llvm.dir/rule] Error 2
make: *** [Makefile:34184: check-llvm] Error 2

tomtor · 2025-06-23T10:11:22Z

The failing tests are related to the emitting of a relocation label. So this is expected, and we should adapt these tests if we agree on this PR.

@benshi001 This was my comment before your comment. These failing tests are logical, because we generate different assembly now. Will study the tests, but these tests should be changed in the context of this PR.
However, it makes no sense to change them unless we decide that we are interested in fixing -mrelax for AVR.

tomtor · 2025-06-23T10:31:25Z

The PR in the current state will still fix #133579
but PCREL_7 cases could fail with -mrelax.

@benshi001 Rewite just the two tests for the changed assembly (instead of exit 0) ?
Rewrite all tests if we agree that PCREL_7 should be changed too? How to proceed?

Edit: two MC/* calls still fail, but I will not make any changes to this PR until it is clear how to proceed.

Patryk27 · 2025-06-23T18:43:53Z

We don't emit relocations for jumps deliberately, as a fix for something else:

I recall we - cc @benshi001 -'ve had some discussion on whether we should emit relocations always (as GCC does) or only when needed (which is the current approach), but I can't find it on GitHub now. Anywhere, the system is what the system does and so the current approach is to avoid emitting relocations, which - in a hindsight, of course - is not compatible with relaxation.

I think the proper fix would be to go back to emitting relocations always, not only conditionally - i.e. change this:

llvm-project/llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp

Line 522 in b215c8e

case AVR::fixup_7_pcrel:

... into:

  case AVR::fixup_7_pcrel:
  case AVR::fixup_13_pcrel:
  case AVR::fixup_call:
    return true;

The only downside I see is that the generated *.elf files will be somewhat bigger (every jump will need to have its own relocation), but this doesn't really affect the final binary (which is linked and thus doesn't contain relocations anyway).

Thoughts?

tomtor · 2025-06-23T20:34:41Z

@Patryk27 Thanks for the (historic) info. I will study the current code base a bit more to gain a deeper understanding.

As you already mentioned, ELF object size cannot be a valid reason to generate broken code, as the current default is -mrelax

tomtor · 2025-06-24T10:38:10Z

@Patryk27 I updated one of the now failing tests:

For the ATTINY85 test the brne .+2 is replaced by a brne .-2 and a next line with the relocation (+0x8 looks good).
The .+2 makes no sense, but this isn't an issue because it is fixed when loading? I will check that, but it does not look very natural. The ; AVR3-NEXT: jmp 0x0 at the end is better, the 0x0 signaling that it is not yet known.

Before I proceed with editing the tests (a lot of them), does this look OK to you?

--- a/llvm/test/CodeGen/AVR/branch-relaxation-long-forward.ll
+++ b/llvm/test/CodeGen/AVR/branch-relaxation-long-forward.ll
@@ -5,15 +5,18 @@
 ; ATTINY85: <main>:
 ; ATTINY85-NEXT: andi r24, 0x1
 ; ATTINY85-NEXT: cpi r24, 0x0
-; ATTINY85-NEXT: brne .+2
-; ATTINY85-NEXT: rjmp .-4092
+; ATTINY85-NEXT: brne .-2
+; ATTINY85-NEXT: R_AVR_7_PCREL .text+0x8
+; ATTINY85-NEXT: rjmp .-2
+; ATTINY85-NEXT: R_AVR_13_PCREL .text+0x100c
 ; ATTINY85: ldi r24, 0x3
 ; ATTINY85-NEXT: ret

 ; AVR25: <main>:
 ; AVR25-NEXT: andi r24, 0x1
 ; AVR25-NEXT: cpi r24, 0x0
-; AVR25-NEXT: brne .+2
+; AVR25-NEXT: brne .-2
+; AVR25-NEXT: R_AVR_7_PCREL .text+0x8
 ; AVR25-NEXT: rjmp .-2
 ; AVR25-NEXT: R_AVR_13_PCREL .text+0x100c
 ; AVR25: ldi r24, 0x3
@@ -22,7 +25,8 @@
 ; AVR3: <main>:
 ; AVR3-NEXT: andi r24, 0x1
 ; AVR3-NEXT: cpi r24, 0x0
-; AVR3-NEXT: brne .+4
+; AVR3-NEXT: brne .-2
+; AVR3-NEXT: R_AVR_7_PCREL .text+0xa
 ; AVR3-NEXT: jmp 0x0
 ; AVR3-NEXT: R_AVR_CALL .text+0x100e
 ; AVR3: ldi r24, 0x3

Patryk27 · 2025-06-24T11:35:38Z

Yes, that's alright - -2 stems from the fact that relocatable jumps are emitted with offset of zero (after all, linker will overwrite the instruction anyway) and because jumps are relative to the beginning of the current instruction, so you end up with Value = -2 right after this bit:

llvm-project/llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp

Line 63 in 1dc46d4

// Jumps are relative to the current instruction.

llvmbot · 2025-06-24T13:50:04Z

@llvm/pr-subscribers-mc

Author: Tom Vijlbrief (tomtor)

Changes

Fix #133579 -mrelax issue

Full diff: https://github.com/llvm/llvm-project/pull/145291.diff

26 Files Affected:

(modified) llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp (+1-13)
(modified) llvm/test/CodeGen/AVR/branch-relaxation-long-backward.ll (+8-4)
(modified) llvm/test/CodeGen/AVR/branch-relaxation-long-forward.ll (+8-4)
(modified) llvm/test/CodeGen/AVR/jmp.ll (+2-1)
(modified) llvm/test/MC/AVR/inst-brbc.s (+4-2)
(modified) llvm/test/MC/AVR/inst-brbs.s (+4-2)
(modified) llvm/test/MC/AVR/inst-brcc.s (+8-4)
(modified) llvm/test/MC/AVR/inst-brcs.s (+7-4)
(modified) llvm/test/MC/AVR/inst-breq.s (+6-4)
(modified) llvm/test/MC/AVR/inst-brge.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brhc.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brhs.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brid.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brie.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brlo.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brlt.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brmi.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brne.s (+6-4)
(modified) llvm/test/MC/AVR/inst-brpl.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brsh.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brtc.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brts.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brvc.s (+6-3)
(modified) llvm/test/MC/AVR/inst-brvs.s (+6-3)
(modified) llvm/test/MC/AVR/inst-rcall.s (+7-5)
(modified) llvm/test/MC/AVR/inst-rjmp.s (+18-8)

diff --git a/llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp b/llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp
index 41341387b42c2..b26bbdb514c24 100644
--- a/llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp
+++ b/llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp
@@ -520,19 +520,7 @@ bool AVRAsmBackend::forceRelocation(const MCFragment &F, const MCFixup &Fixup,
     return false;
 
   case AVR::fixup_7_pcrel:
-  case AVR::fixup_13_pcrel: {
-    uint64_t Offset = Target.getConstant();
-    uint64_t Size = AVRAsmBackend::getFixupKindInfo(Fixup.getKind()).TargetSize;
-
-    // If the jump is too large to encode it, fall back to a relocation.
-    //
-    // Note that trying to actually link that relocation *would* fail, but the
-    // hopes are that the module we're currently compiling won't be actually
-    // linked to the final binary.
-    return !adjust::adjustRelativeBranch(Size, Fixup, Offset,
-                                         getContext().getSubtargetInfo());
-  }
-
+  case AVR::fixup_13_pcrel:
   case AVR::fixup_call:
     return true;
   }
diff --git a/llvm/test/CodeGen/AVR/branch-relaxation-long-backward.ll b/llvm/test/CodeGen/AVR/branch-relaxation-long-backward.ll
index 3562b93a22503..f49624d7ea059 100644
--- a/llvm/test/CodeGen/AVR/branch-relaxation-long-backward.ll
+++ b/llvm/test/CodeGen/AVR/branch-relaxation-long-backward.ll
@@ -5,15 +5,18 @@
 ; ATTINY85: <main>:
 ; ATTINY85-NEXT: andi r24, 0x1
 ; ATTINY85: cpi r24, 0x0
-; ATTINY85-NEXT: breq .+2
-; ATTINY85-NEXT: rjmp .+4086
+; ATTINY85-NEXT: breq .-2
+; ATTINY85-NEXT: R_AVR_7_PCREL .text+0x100c
+; ATTINY85-NEXT: rjmp .-2
+; ATTINY85-NEXT: R_AVR_13_PCREL .text+0x2
 ; ATTINY85: ldi r24, 0x3
 ; ATTINY85-NEXT: ret
 
 ; AVR25: <main>:
 ; AVR25-NEXT: andi r24, 0x1
 ; AVR25: cpi r24, 0x0
-; AVR25-NEXT: breq .+2
+; AVR25-NEXT: breq .-2
+; AVR25-NEXT: R_AVR_7_PCREL .text+0x100c
 ; AVR25-NEXT: rjmp .-2
 ; AVR25-NEXT: R_AVR_13_PCREL .text+0x2
 ; AVR25: ldi r24, 0x3
@@ -22,7 +25,8 @@
 ; AVR3: <main>:
 ; AVR3-NEXT: andi r24, 0x1
 ; AVR3: cpi r24, 0x0
-; AVR3-NEXT: breq .+4
+; AVR3-NEXT: breq .-2
+; AVR3-NEXT: R_AVR_7_PCREL .text+0x100e
 ; AVR3-NEXT: jmp 0x0
 ; AVR3-NEXT: R_AVR_CALL .text+0x2
 ; AVR3: ldi r24, 0x3
diff --git a/llvm/test/CodeGen/AVR/branch-relaxation-long-forward.ll b/llvm/test/CodeGen/AVR/branch-relaxation-long-forward.ll
index a51cf42d5de8b..de4d4465a021d 100644
--- a/llvm/test/CodeGen/AVR/branch-relaxation-long-forward.ll
+++ b/llvm/test/CodeGen/AVR/branch-relaxation-long-forward.ll
@@ -5,15 +5,18 @@
 ; ATTINY85: <main>:
 ; ATTINY85-NEXT: andi r24, 0x1
 ; ATTINY85-NEXT: cpi r24, 0x0
-; ATTINY85-NEXT: brne .+2
-; ATTINY85-NEXT: rjmp .-4092
+; ATTINY85-NEXT: brne .-2
+; ATTINY85-NEXT: R_AVR_7_PCREL .text+0x8
+; ATTINY85-NEXT: rjmp .-2
+; ATTINY85-NEXT: R_AVR_13_PCREL .text+0x100c
 ; ATTINY85: ldi r24, 0x3
 ; ATTINY85-NEXT: ret
 
 ; AVR25: <main>:
 ; AVR25-NEXT: andi r24, 0x1
 ; AVR25-NEXT: cpi r24, 0x0
-; AVR25-NEXT: brne .+2
+; AVR25-NEXT: brne .-2
+; AVR25-NEXT: R_AVR_7_PCREL .text+0x8
 ; AVR25-NEXT: rjmp .-2
 ; AVR25-NEXT: R_AVR_13_PCREL .text+0x100c
 ; AVR25: ldi r24, 0x3
@@ -22,7 +25,8 @@
 ; AVR3: <main>:
 ; AVR3-NEXT: andi r24, 0x1
 ; AVR3-NEXT: cpi r24, 0x0
-; AVR3-NEXT: brne .+4
+; AVR3-NEXT: brne .-2
+; AVR3-NEXT: R_AVR_7_PCREL .text+0xa
 ; AVR3-NEXT: jmp 0x0
 ; AVR3-NEXT: R_AVR_CALL .text+0x100e
 ; AVR3: ldi r24, 0x3
diff --git a/llvm/test/CodeGen/AVR/jmp.ll b/llvm/test/CodeGen/AVR/jmp.ll
index 95dfff4836b4e..1cbc6375dea17 100644
--- a/llvm/test/CodeGen/AVR/jmp.ll
+++ b/llvm/test/CodeGen/AVR/jmp.ll
@@ -18,7 +18,8 @@ declare i8 @bar(i8);
 ; CHECK: rcall   .-2
 ; CHECK-NEXT: 00000000: R_AVR_13_PCREL bar
 ; CHECK-NEXT: cpi     r24, 0x7b
-; CHECK-NEXT: brne    .+4
+; CHECK-NEXT: brne    .-2
+; CHECK-NEXT: R_AVR_7_PCREL .text+0xa
 ; CHECK-NEXT: ldi     r24, 0x64
 ; CHECK-NEXT: ret
 ; CHECK-NEXT: ldi     r24, 0xc8
diff --git a/llvm/test/MC/AVR/inst-brbc.s b/llvm/test/MC/AVR/inst-brbc.s
index 6d96393b42ad1..bf73188cf7c3f 100644
--- a/llvm/test/MC/AVR/inst-brbc.s
+++ b/llvm/test/MC/AVR/inst-brbc.s
@@ -15,8 +15,10 @@ foo:
 ; CHECK: brcc .Ltmp1-16+2  ; encoding: [0bAAAAA000,0b111101AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 23 f4   brvc .+8
-; INST-NEXT: c0 f7   brsh .-16
+; INST-NEXT: fb f7   brvc .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0xa
+; INST-NEXT: f8 f7   brsh .-2
+; INST-NEXT: R_AVR_7_PCREL .text-0xc
 ; INST-NEXT: 59 f7   brne .-42
 ; INST-NEXT: 52 f7   brpl .-44
 ; INST-NEXT: 4c f7   brge .-46
diff --git a/llvm/test/MC/AVR/inst-brbs.s b/llvm/test/MC/AVR/inst-brbs.s
index 9dde5e16abde3..3e64ebce542b8 100644
--- a/llvm/test/MC/AVR/inst-brbs.s
+++ b/llvm/test/MC/AVR/inst-brbs.s
@@ -14,8 +14,10 @@ foo:
 ; CHECK: brcs .Ltmp1-12+2  ; encoding: [0bAAAAA000,0b111100AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 23 f0   brvs .+8
-; INST-NEXT: d0 f3   brlo .-12
+; INST-NEXT: fb f3   brvs .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0xa
+; INST-NEXT: f8 f3   brlo .-2
+; INST-NEXT: R_AVR_7_PCREL .text-0x8
 ; INST-NEXT: 59 f3   breq .-42
 ; INST-NEXT: 52 f3   brmi .-44
 ; INST-NEXT: 4c f3   brlt .-46
diff --git a/llvm/test/MC/AVR/inst-brcc.s b/llvm/test/MC/AVR/inst-brcc.s
index 0edefa167ac44..eba05e06bb43b 100644
--- a/llvm/test/MC/AVR/inst-brcc.s
+++ b/llvm/test/MC/AVR/inst-brcc.s
@@ -18,7 +18,11 @@ bar:
 ; CHECK: brcc bar            ; encoding: [0bAAAAA000,0b111101AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 08 f5      brsh .+66
-; INST-NEXT: a8 f7      brsh .-22
-; INST-NEXT: 08 f5      brsh .+66
-; INST-NEXT: 00 f4      brsh .+0
+; INST-NEXT: f8 f7      brsh .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x44
+; INST-NEXT: f8 f7      brsh .-2
+; INST-NEXT: R_AVR_7_PCREL .text-0x12
+; INST-NEXT: f8 f7      brsh .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x48
+; INST-NEXT: f8 f7      brsh .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x8
diff --git a/llvm/test/MC/AVR/inst-brcs.s b/llvm/test/MC/AVR/inst-brcs.s
index ea8a3f527c9e4..1aea7216a13de 100644
--- a/llvm/test/MC/AVR/inst-brcs.s
+++ b/llvm/test/MC/AVR/inst-brcs.s
@@ -18,7 +18,10 @@ bar:
 ; CHECK: brcs bar           ; encoding: [0bAAAAA000,0b111100AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 20 f0      brlo .+8
-; INST-NEXT: 10 f0      brlo .+4
-; INST-NEXT: 20 f0      brlo .+8
-; INST-NEXT: 00 f0      brlo .+0
+; INST-NEXT: f8 f3      brlo .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0xa
+; INST-NEXT: f8 f3      brlo .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x8
+; INST-NEXT: f8 f3      brlo .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0xe
+; INST-NEXT: f8 f3      brlo .-2
diff --git a/llvm/test/MC/AVR/inst-breq.s b/llvm/test/MC/AVR/inst-breq.s
index d916f6dc18c8f..59bbb13df13e0 100644
--- a/llvm/test/MC/AVR/inst-breq.s
+++ b/llvm/test/MC/AVR/inst-breq.s
@@ -18,7 +18,9 @@ bar:
 ; CHECK: brbs    1, bar            ; encoding: [0bAAAAA001,0b111100AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: b9 f3      breq .-18
-; INST-NEXT: d1 f3      breq .-12
-; INST-NEXT: b9 f3      breq .-18
-; INST-NEXT: 01 f0      breq .+0
+; INST-NEXT: f9 f3      breq .-2
+; INST-NEXT: R_AVR_7_PCREL .text-0x10
+; INST-NEXT: f9 f3      breq .-2
+; INST-NEXT: R_AVR_7_PCREL .text-0x8
+; INST-NEXT: f9 f3      breq .-2
+; INST-NEXT: R_AVR_7_PCREL .text-0xc
diff --git a/llvm/test/MC/AVR/inst-brge.s b/llvm/test/MC/AVR/inst-brge.s
index 3a8fd727d773e..ed96d8961ba16 100644
--- a/llvm/test/MC/AVR/inst-brge.s
+++ b/llvm/test/MC/AVR/inst-brge.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brge bar            ; encoding: [0bAAAAA100,0b111101AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: cc f4      brge .+50
-; INST-NEXT: ac f4      brge .+42
-; INST-NEXT: 04 f4      brge .+0
+; INST-NEXT: fc f7      brge .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x34
+; INST-NEXT: fc f7      brge .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x2e
+; INST-NEXT: fc f7      brge .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brhc.s b/llvm/test/MC/AVR/inst-brhc.s
index 4fc55b6ab0347..8421c9112edd6 100644
--- a/llvm/test/MC/AVR/inst-brhc.s
+++ b/llvm/test/MC/AVR/inst-brhc.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brhc bar            ; encoding: [0bAAAAA101,0b111101AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 35 f4      brhc .+12
-; INST-NEXT: 3d f4      brhc .+14
-; INST-NEXT: 05 f4      brhc .+0
+; INST-NEXT: fd f7      brhc .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0xe
+; INST-NEXT: fd f7      brhc .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x12
+; INST-NEXT: fd f7      brhc .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brhs.s b/llvm/test/MC/AVR/inst-brhs.s
index d0968753cded2..a3777b40b25d0 100644
--- a/llvm/test/MC/AVR/inst-brhs.s
+++ b/llvm/test/MC/AVR/inst-brhs.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brhs bar            ; encoding: [0bAAAAA101,0b111100AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: fd f2      brhs .-66
-; INST-NEXT: 3d f0      brhs .+14
-; INST-NEXT: 05 f0      brhs .+0
+; INST-NEXT: fd f3      brhs .-2
+; INST-NEXT: R_AVR_7_PCREL .text-0x40
+; INST-NEXT: fd f3      brhs .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x12
+; INST-NEXT: fd f3      brhs .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brid.s b/llvm/test/MC/AVR/inst-brid.s
index 2a3a30f905cf5..888ae02ed6522 100644
--- a/llvm/test/MC/AVR/inst-brid.s
+++ b/llvm/test/MC/AVR/inst-brid.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brid bar            ; encoding: [0bAAAAA111,0b111101AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: af f4      brid .+42
-; INST-NEXT: ff f4      brid .+62
-; INST-NEXT: 07 f4      brid .+0
+; INST-NEXT: ff f7      brid .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x2c
+; INST-NEXT: ff f7      brid .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x42
+; INST-NEXT: ff f7      brid .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brie.s b/llvm/test/MC/AVR/inst-brie.s
index 4f867ae99852a..1d175f184baa7 100644
--- a/llvm/test/MC/AVR/inst-brie.s
+++ b/llvm/test/MC/AVR/inst-brie.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brie bar            ; encoding: [0bAAAAA111,0b111100AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 57 f0      brie .+20
-; INST-NEXT: a7 f0      brie .+40
-; INST-NEXT: 07 f0      brie .+0
+; INST-NEXT: ff f3      brie .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x16
+; INST-NEXT: ff f3      brie .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x2c
+; INST-NEXT: ff f3      brie .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brlo.s b/llvm/test/MC/AVR/inst-brlo.s
index 48499aa69926b..4b57e77ed77b1 100644
--- a/llvm/test/MC/AVR/inst-brlo.s
+++ b/llvm/test/MC/AVR/inst-brlo.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brlo bar            ; encoding: [0bAAAAA000,0b111100AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 30 f0      brlo .+12
-; INST-NEXT: 70 f0      brlo .+28
-; INST-NEXT: 00 f0      brlo .+0
+; INST-NEXT: f8 f3      brlo .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0xe
+; INST-NEXT: f8 f3      brlo .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x20
+; INST-NEXT: f8 f3      brlo .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brlt.s b/llvm/test/MC/AVR/inst-brlt.s
index e16fd05b3e144..58e57c4dc7e1d 100644
--- a/llvm/test/MC/AVR/inst-brlt.s
+++ b/llvm/test/MC/AVR/inst-brlt.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brlt bar            ; encoding: [0bAAAAA100,0b111100AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 44 f0    brlt .+16
-; INST-NEXT: 0c f0    brlt .+2
-; INST-NEXT: 04 f0    brlt .+0
+; INST-NEXT: fc f3    brlt .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x12
+; INST-NEXT: fc f3    brlt .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
+; INST-NEXT: fc f3    brlt .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brmi.s b/llvm/test/MC/AVR/inst-brmi.s
index 0d46af8b75969..c40644885fdcf 100644
--- a/llvm/test/MC/AVR/inst-brmi.s
+++ b/llvm/test/MC/AVR/inst-brmi.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brmi bar            ; encoding: [0bAAAAA010,0b111100AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 0a f1      brmi .+66
-; INST-NEXT: ea f0      brmi .+58
-; INST-NEXT: 02 f0      brmi .+0
+; INST-NEXT: fa f3      brmi .-2
+; INST-NEXT: VR_7_PCREL .text+0x44
+; INST-NEXT: fa f3      brmi .-2
+; INST-NEXT: VR_7_PCREL .text+0x3e
+; INST-NEXT: fa f3      brmi .-2
+; INST-NEXT: VR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brne.s b/llvm/test/MC/AVR/inst-brne.s
index e87813a60b504..cf7e70d919659 100644
--- a/llvm/test/MC/AVR/inst-brne.s
+++ b/llvm/test/MC/AVR/inst-brne.s
@@ -18,7 +18,9 @@ bar:
 ; CHECK: brbc    1, bar            ; encoding: [0bAAAAA001,0b111101AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 29 f4      brne .+10
-; INST-NEXT: 09 f4      brne .+2
-; INST-NEXT: 29 f4      brne .+10
-; INST-NEXT: 01 f4      brne .+0
+; INST-NEXT: f9 f7      brne .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0xc
+; INST-NEXT: f9 f7      brne .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
+; INST-NEXT: f9 f7      brne .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x10
diff --git a/llvm/test/MC/AVR/inst-brpl.s b/llvm/test/MC/AVR/inst-brpl.s
index 34877961bf328..9049e24197b89 100644
--- a/llvm/test/MC/AVR/inst-brpl.s
+++ b/llvm/test/MC/AVR/inst-brpl.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brpl bar            ; encoding: [0bAAAAA010,0b111101AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: d2 f7      brpl .-12
-; INST-NEXT: 4a f4      brpl .+18
-; INST-NEXT: 02 f4      brpl .+0
+; INST-NEXT: fa f7      brpl .-2
+; INST-NEXT: R_AVR_7_PCREL .text-0xa
+; INST-NEXT: fa f7      brpl .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x16
+; INST-NEXT: fa f7      brpl .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brsh.s b/llvm/test/MC/AVR/inst-brsh.s
index be0a06c445e65..0f32fbae73357 100644
--- a/llvm/test/MC/AVR/inst-brsh.s
+++ b/llvm/test/MC/AVR/inst-brsh.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brsh bar            ; encoding: [0bAAAAA000,0b111101AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 80 f4      brsh .+32
-; INST-NEXT: 18 f5      brsh .+70
-; INST-NEXT: 00 f4      brsh .+0
+; INST-NEXT: f8 f7      brsh .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x22
+; INST-NEXT: f8 f7      brsh .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x4a
+; INST-NEXT: f8 f7      brsh .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brtc.s b/llvm/test/MC/AVR/inst-brtc.s
index 312c55c3f4729..731b495a787ea 100644
--- a/llvm/test/MC/AVR/inst-brtc.s
+++ b/llvm/test/MC/AVR/inst-brtc.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brtc bar            ; encoding: [0bAAAAA110,0b111101AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: d6 f4      brtc .+52
-; INST-NEXT: ce f4      brtc .+50
-; INST-NEXT: 06 f4      brtc .+0
+; INST-NEXT: fe f7      brtc .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x36
+; INST-NEXT: fe f7      brtc .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x36
+; INST-NEXT: fe f7      brtc .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brts.s b/llvm/test/MC/AVR/inst-brts.s
index 40ef6af5eef16..bb00acb55d28c 100644
--- a/llvm/test/MC/AVR/inst-brts.s
+++ b/llvm/test/MC/AVR/inst-brts.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brts bar            ; encoding: [0bAAAAA110,0b111100AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 4e f0      brts .+18
-; INST-NEXT: 5e f0      brts .+22
-; INST-NEXT: 06 f0      brts .+0
+; INST-NEXT: fe f3      brts .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x14
+; INST-NEXT: fe f3      brts .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x1a
+; INST-NEXT: fe f3      brts .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brvc.s b/llvm/test/MC/AVR/inst-brvc.s
index d493ff1fbf544..f65e735440274 100644
--- a/llvm/test/MC/AVR/inst-brvc.s
+++ b/llvm/test/MC/AVR/inst-brvc.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brvc bar            ; encoding: [0bAAAAA011,0b111101AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 93 f7      brvc .-28
-; INST-NEXT: 0b f7      brvc .-62
-; INST-NEXT: 03 f4      brvc .+0
+; INST-NEXT: fb f7      brvc .-2
+; INST-NEXT: R_AVR_7_PCREL .text-0x1a
+; INST-NEXT: fb f7      brvc .-2
+; INST-NEXT: R_AVR_7_PCREL .text-0x3a
+; INST-NEXT: fb f7      brvc .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-brvs.s b/llvm/test/MC/AVR/inst-brvs.s
index 07755d8aea21f..a5b7e4b7904e6 100644
--- a/llvm/test/MC/AVR/inst-brvs.s
+++ b/llvm/test/MC/AVR/inst-brvs.s
@@ -16,6 +16,9 @@ bar:
 ; CHECK: brvs bar            ; encoding: [0bAAAAA011,0b111100AA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 4b f0      brvs .+18
-; INST-NEXT: 83 f0      brvs .+32
-; INST-NEXT: 03 f0      brvs .+0
+; INST-NEXT: fb f3      brvs .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x14
+; INST-NEXT: fb f3      brvs .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x24
+; INST-NEXT: fb f3      brvs .-2
+; INST-NEXT: R_AVR_7_PCREL .text+0x6
diff --git a/llvm/test/MC/AVR/inst-rcall.s b/llvm/test/MC/AVR/inst-rcall.s
index 1da6e7f5dddf9..572153c15996b 100644
--- a/llvm/test/MC/AVR/inst-rcall.s
+++ b/llvm/test/MC/AVR/inst-rcall.s
@@ -17,8 +17,10 @@ foo:
 ; CHECK: rcall .Ltmp3+46+2  ; encoding: [A,0b1101AAAA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 00 d0    rcall .+0
-; INST-NEXT: fc df    rcall .-8
-; INST-NEXT: 06 d0    rcall .+12
-; INST-NEXT: 17 d0    rcall .+46
-; INST-NEXT: ea df    rcall .-44
+; INST-NEXT: ff df    rcall .-2
+; INST-NEXT: R_AVR_13_PCREL .text+0x2
+; INST-NEXT: ff df    rcall .-2
+; INST-NEXT: R_AVR_13_PCREL .text-0x4
+; INST-NEXT: ff df    rcall .-2
+; INST-NEXT: R_AVR_13_PCREL .text+0x12
+; INST-NEXT: ff df    rcall .-2
diff --git a/llvm/test/MC/AVR/inst-rjmp.s b/llvm/test/MC/AVR/inst-rjmp.s
index 6712319bbc268..6ac6343894cb8 100644
--- a/llvm/test/MC/AVR/inst-rjmp.s
+++ b/llvm/test/MC/AVR/inst-rjmp.s
@@ -33,18 +33,28 @@ x:
 ; CHECK: rjmp .Ltmp6+4094+2 ; encoding: [A,0b1100AAAA]
 
 ; INST-LABEL: <foo>:
-; INST-NEXT: 01 c0      rjmp  .+2
 ; INST-NEXT: ff cf      rjmp  .-2
-; INST-NEXT: fd cf      rjmp  .-6
-; INST-NEXT: 04 c0      rjmp  .+8
-; INST-NEXT: 01 c0      rjmp  .+2
-; INST-NEXT: 00 c0      rjmp  .+0
+; INST-NEXT: R_AVR_13_PCREL .text+0x4
+; INST-NEXT: ff cf      rjmp  .-2
+; INST-NEXT: R_AVR_13_PCREL .text+0x2
+; INST-NEXT: ff cf      rjmp  .-2
+; INST-NEXT: R_AVR_13_PCREL .text
+; INST-NEXT: ff cf      rjmp  .-2
+; INST-NEXT: R_AVR_13_PCREL .text+0x10
+; INST-NEXT: ff cf      rjmp  .-2
+; INST-NEXT: R_AVR_13_PCREL .text+0xc
+; INST-NEXT: ff cf      rjmp  .-2
+; INST-NEXT: R_AVR_13_PCREL .text+0xc
 ; INST-EMPTY:
 ; INST-LABEL: <end>:
-; INST-NEXT: fe cf      rjmp  .-4
-; INST-NEXT: fd cf      rjmp  .-6
+; INST-NEXT: ff cf      rjmp  .-2
+; INST-NEXT: R_AVR_13_PCREL .text+0xa
+; INST-NEXT: ff cf      rjmp  .-2
+; INST-NEXT: R_AVR_13_PCREL .text+0xa
 ; INST-EMPTY:
 ; INST-LABEL: <x>:
 ; INST-NEXT: ff cf      rjmp  .-2
+; INST-NEXT: R_AVR_13_PCREL .text+0x10
 ; INST-NEXT: 0f c0      rjmp  .+30
-; INST-NEXT: ff c7      rjmp  .+4094
+; INST-NEXT: ff cf      rjmp  .-2
+; INST-NEXT: R_AVR_13_PCREL .text+0x1014

benshi001 · 2025-06-25T01:38:49Z

llvm/lib/Target/AVR/MCTargetDesc/AVRAsmBackend.cpp

-                                         getContext().getSubtargetInfo());
-  }
-
+  case AVR::fixup_13_pcrel:


As previous discussion with @Patryk27 eariler this year, such change is so aggressive, which I have to consider more than just fix the -mrelax issue.

benshi001 self-requested a review June 23, 2025 09:40

benshi001 requested changes Jun 23, 2025

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benshi001 mentioned this pull request Jun 24, 2025

[AVR] -mrelax does not work for a simple LED blink program #133579

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[AVR] Emit relocation record for local branch

ac2988a

tomtor force-pushed the avr_fix_reloc_local_branch branch from 3bf719f to ac2988a Compare June 24, 2025 13:49

llvmbot added the mc Machine (object) code label Jun 24, 2025

tomtor requested a review from benshi001 June 24, 2025 15:41

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[AVR] Emit relocation record for local branch #145291

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