[lld] [lld] Add thunks for hexagon (PR #111217)

[Fangrui Song via llvm-commits]

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@@ -252,6 +259,34 @@ static uint32_t findMaskR16(Ctx &ctx, uint32_t insn) {
 
 static void or32le(uint8_t *p, int32_t v) { write32le(p, read32le(p) | v); }
 
+bool Hexagon::inBranchRange(RelType type, uint64_t src, uint64_t dst) const {
+  int64_t offset = dst - src;
+  switch (type) {
+  case llvm::ELF::R_HEX_B22_PCREL:
+  case llvm::ELF::R_HEX_PLT_B22_PCREL:
+  case llvm::ELF::R_HEX_GD_PLT_B22_PCREL:
+  case llvm::ELF::R_HEX_LD_PLT_B22_PCREL:
+    return llvm::isInt<22>(offset >> 2);
+  case llvm::ELF::R_HEX_B15_PCREL:
+    return llvm::isInt<15>(offset >> 2);
+    break;
+  case llvm::ELF::R_HEX_B13_PCREL:
+    return llvm::isInt<13>(offset >> 2);
+    break;
+  case llvm::ELF::R_HEX_B9_PCREL:
+    return llvm::isInt<9>(offset >> 2);
+  default:
+    return true;
+  }
+  llvm_unreachable("unsupported relocation");
+}
+
+bool Hexagon::needsThunk(RelExpr expr, RelType type, const InputFile *file,
+                         uint64_t branchAddr, const Symbol &s,
+                         int64_t a) const {
+  return !ctx.target->inBranchRange(type, branchAddr, s.getVA(ctx, a));
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MaskRay wrote:

if type is unexpected, needsThunk should return false to avoid a unreachable failure in inBranchRange.

https://github.com/llvm/llvm-project/pull/111217