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llvm-project/llvm/test/MC/RISCV/long-conditional-jump.s
Fangrui Song bb03cdcb44
RISCV: Remove shouldForceRelocation and unneeded relocations 
Follow-up to #140494

`shouldForceRelocation` is conservative and produces redundant
relocations.

For example, RISCVAsmBackend::ForceRelocs (introduced to support mixed
relax/norelax code) leads to redundant relocations in the following
example adapted from #77436

```
.option norelax
j label
// For assembly input, RISCVAsmParser::ParseInstruction sets ForceRelocs (https://reviews.llvm.org/D46423).
// For direct object emission, RISCVELFStreamer sets ForceRelocs (#77436)
.option relax
call foo  // linker-relaxable

.option norelax
j label   // redundant relocation due to ForceRelocs
.option relax

label:
```

Root problem: The `isSymbolRefDifferenceFullyResolvedImpl` condition in
MCAssembler::evaluateFixup does not check whether two locations are
separated by a fragment whose size can be indeterminate due to linker
instruction (e.g. MCDataFragment with relaxation, or MCAlignFragment
due to indeterminate start offst).

This patch

* Updates the fragment walk code in
  `attemptToFoldSymbolOffsetDifference` to treat MCRelaxableFragment
  (for --riscv-asm-relax-branches) as fixed size after finishLayout.
* Adds a condition in `addReloc` to complement
  `isSymbolRefDifferenceFullyResolvedImpl`.
* Removes the no longer needed `shouldForceRelocation`.

This fragment walk code path handles nicely handles
mixed relax/norelax case from
https://discourse.llvm.org/t/possible-problem-related-to-subtarget-usage/75283
and allows us to remove `MCSubtargetInfo` argument (#73721) as a follow-up.

This fragment walk code should be avoided in the absence of
linker-relaxable fragments within the current section.

Adjust two bolt/test/RISCV tests (#141310)

Pull Request: https://github.com/llvm/llvm-project/pull/140692
2025-05-23 18:44:15 -07:00

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# RUN: llvm-mc -filetype=obj -triple=riscv64 %s \
# RUN: | llvm-objdump -d -M no-aliases - \
# RUN: | FileCheck --check-prefix=CHECK-INST %s
# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+c %s \
# RUN: | llvm-objdump -d -M no-aliases - \
# RUN: | FileCheck --check-prefix=CHECK-INST-C %s
# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+relax %s \
# RUN: | llvm-objdump -dr -M no-aliases - \
# RUN: | FileCheck --check-prefix=CHECK-INST-RELAX %s
# RUN: llvm-mc -filetype=obj -triple=riscv64 -mattr=+c,+relax %s \
# RUN: | llvm-objdump -dr -M no-aliases - \
# RUN: | FileCheck --check-prefix=CHECK-INST-C-RELAX %s
.text
.type test,@function
test:
# CHECK-INST: beq a0, a1, 0x8
# CHECK-INST-NEXT: jal zero, 0x1458
# CHECK-INST-C: beq a0, a1, 0x8
# CHECK-INST-C-NEXT: jal zero, 0x1458
# CHECK-INST-RELAX: beq a0, a1, 0x8
# CHECK-INST-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-RELAX-NEXT: R_RISCV_JAL .L1
# CHECK-INST-C-RELAX: beq a0, a1, 0x8
# CHECK-INST-C-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-C-RELAX-NEXT: R_RISCV_JAL .L1
bne a0, a1, .L1
call relax
.fill 1300-2, 4, 0
.L1:
ret
# CHECK-INST: bne a0, a1, 0x1464
# CHECK-INST-NEXT: jal zero, 0x28b4
# CHECK-INST-C: bne a0, a1, 0x1462
# CHECK-INST-C-NEXT: jal zero, 0x28b2
# CHECK-INST-RELAX: bne a0, a1, 0x1464
# CHECK-INST-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-C-RELAX: bne a0, a1, 0x1462
# CHECK-INST-C-RELAX-NEXT: jal zero, {{.*}}
beq a0, a1, .L2
.fill 1300, 4, 0
.L2:
ret
# CHECK-INST: bge a0, a1, 0x28c0
# CHECK-INST-NEXT: jal zero, 0x3d10
# CHECK-INST-C: bge a0, a1, 0x28bc
# CHECK-INST-C-NEXT: jal zero, 0x3d0c
# CHECK-INST-RELAX: bge a0, a1, 0x28c0
# CHECK-INST-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-C-RELAX: bge a0, a1, 0x28bc
# CHECK-INST-C-RELAX-NEXT: jal zero, {{.*}}
blt a0, a1, .L3
.fill 1300, 4, 0
.L3:
ret
# CHECK-INST: blt a0, a1, 0x3d1c
# CHECK-INST-NEXT: jal zero, 0x516c
# CHECK-INST-C: blt a0, a1, 0x3d16
# CHECK-INST-C-NEXT: jal zero, 0x5166
# CHECK-INST-RELAX: blt a0, a1, 0x3d1c
# CHECK-INST-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-C-RELAX: blt a0, a1, 0x3d16
# CHECK-INST-C-RELAX-NEXT: jal zero, {{.*}}
bge a0, a1, .L4
.fill 1300, 4, 0
.L4:
ret
# CHECK-INST: bgeu a0, a1, 0x5178
# CHECK-INST-NEXT: jal zero, 0x65c8
# CHECK-INST-C: bgeu a0, a1, 0x5170
# CHECK-INST-C-NEXT: jal zero, 0x65c0
# CHECK-INST-RELAX: bgeu a0, a1, 0x5178
# CHECK-INST-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-C-RELAX: bgeu a0, a1, 0x5170
# CHECK-INST-C-RELAX-NEXT: jal zero, {{.*}}
bltu a0, a1, .L5
.fill 1300, 4, 0
.L5:
ret
# CHECK-INST: bltu a0, a1, 0x65d4
# CHECK-INST-NEXT: jal zero, 0x7a24
# CHECK-INST-C: bltu a0, a1, 0x65ca
# CHECK-INST-C-NEXT: jal zero, 0x7a1a
# CHECK-INST-RELAX: bltu a0, a1, 0x65d4
# CHECK-INST-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-C-RELAX: bltu a0, a1, 0x65ca
# CHECK-INST-C-RELAX-NEXT: jal zero, {{.*}}
bgeu a0, a1, .L6
.fill 1300, 4, 0
.L6:
ret
# CHECK-INST: bne a0, zero, 0x7a30
# CHECK-INST-NEXT: jal zero, 0x8e80
# CHECK-INST-C: c.bnez a0, 0x7a22
# CHECK-INST-C-NEXT: jal zero, 0x8e72
# CHECK-INST-RELAX: bne a0, zero, 0x7a30
# CHECK-INST-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-C-RELAX: c.bnez a0, 0x7a22
# CHECK-INST-C-RELAX-NEXT: jal zero, {{.*}}
beqz a0, .L7
.fill 1300, 4, 0
.L7:
ret
# CHECK-INST: bne zero, a0, 0x8e8c
# CHECK-INST-NEXT: jal zero, 0xa2dc
# CHECK-INST-C: c.bnez a0, 0x8e7a
# CHECK-INST-C-NEXT: jal zero, 0xa2ca
# CHECK-INST-RELAX: bne zero, a0, 0x8e8c
# CHECK-INST-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-C-RELAX: c.bnez a0, 0x8e7a
# CHECK-INST-C-RELAX-NEXT: jal zero, {{.*}}
beq x0, a0, .L8
.fill 1300, 4, 0
.L8:
ret
# CHECK-INST: beq a0, zero, 0xa2e8
# CHECK-INST-NEXT: jal zero, 0xb738
# CHECK-INST-C: c.beqz a0, 0xa2d2
# CHECK-INST-C-NEXT: jal zero, 0xb722
# CHECK-INST-RELAX: beq a0, zero, 0xa2e8
# CHECK-INST-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-C-RELAX: c.beqz a0, 0xa2d2
# CHECK-INST-C-RELAX-NEXT: jal zero, {{.*}}
bnez a0, .L9
.fill 1300, 4, 0
.L9:
ret
# CHECK-INST: beq a6, zero, 0xb744
# CHECK-INST-NEXT: jal zero, 0xcb94
# CHECK-INST-C: beq a6, zero, 0xb72c
# CHECK-INST-C-NEXT: jal zero, 0xcb7c
# CHECK-INST-RELAX: beq a6, zero, 0xb744
# CHECK-INST-RELAX-NEXT: jal zero, {{.*}}
# CHECK-INST-C-RELAX: beq a6, zero, 0xb72c
# CHECK-INST-C-RELAX-NEXT: jal zero, {{.*}}
bnez x16, .L10
.fill 1300, 4, 0
.L10:
ret
.Lfunc_end0:
.size test, .Lfunc_end0-test
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