[lld] [RISCV][lld] Gurading lld relaxation for RISCV (PR #130265)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lld

Author: Sharjeel Khan (Sharjeel-Khan)

<details>
<summary>Changes</summary>

Based on the
https://github.com/llvm/llvm-project/issues/123248#issuecomment-2675911618, the relaxation algorithm assumes relaxing a call will shift the later function forward by the same bytes we removed. As some sections are between call and its call target are 32-byte aligned, the call and call target sections might not be the same distance apart anymore. We guard band the relaxation so it stops the relaxation loop and take the last state.

---
Full diff: https://github.com/llvm/llvm-project/pull/130265.diff


1 Files Affected:

- (modified) lld/ELF/Arch/RISCV.cpp (+3) 


``````````diff
diff --git a/lld/ELF/Arch/RISCV.cpp b/lld/ELF/Arch/RISCV.cpp
index 4d8989a21b501..c8a9a7093719e 100644
--- a/lld/ELF/Arch/RISCV.cpp
+++ b/lld/ELF/Arch/RISCV.cpp
@@ -901,6 +901,9 @@ bool RISCV::relaxOnce(int pass) const {
   llvm::TimeTraceScope timeScope("RISC-V relaxOnce");
   if (ctx.arg.relocatable)
     return false;
+  
+  if (pass == 29)
+    return false;
 
   if (pass == 0)
     initSymbolAnchors(ctx);

``````````

</details>


https://github.com/llvm/llvm-project/pull/130265