[PATCH] D153541: [JITLink][RISCV] Support relaxable edges without relaxation pass

[Job Noorman via Phabricator via llvm-commits]

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Relaxable edges are created unconditionally, even when the relaxation
pass will not run. However, they were not recognized by applyFixup
causing them to not be applied.

To support configurations without the relaxation pass, this patch adds
these relaxable edges to applyFixup:

- CallRelaxable: Can be treated as R_RISCV_CALL
- AlignRelaxable: Can simply be ignored

An alternative could be to unconditionally run the relaxation pass, even
in contexts where shouldAddDefaultTargetPasses returns false. However, I
could imagine there being use cases for disabling relaxation which
wouldn't be possible anymore then.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D153541

Files:
  llvm/lib/ExecutionEngine/JITLink/ELF_riscv.cpp


Index: llvm/lib/ExecutionEngine/JITLink/ELF_riscv.cpp
===================================================================
--- llvm/lib/ExecutionEngine/JITLink/ELF_riscv.cpp
+++ llvm/lib/ExecutionEngine/JITLink/ELF_riscv.cpp
@@ -233,6 +233,8 @@
           (RawInstr & 0xFFF) | Imm20 | Imm10_1 | Imm11 | Imm19_12;
       break;
     }
+    case CallRelaxable:
+      // Treat as R_RISCV_CALL when the relaxation pass did not run
     case R_RISCV_CALL_PLT:
     case R_RISCV_CALL: {
       int64_t Value = E.getTarget().getAddress() + E.getAddend() - FixupAddress;
@@ -451,6 +453,9 @@
       *(little32_t *)FixupPtr = Word32;
       break;
     }
+    case AlignRelaxable:
+      // Ignore when the relaxation pass did not run
+      break;
     }
     return Error::success();
   }


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