[PATCH] D71536: [RISCV] Don't crash on unsupported relocations

[Luís Marques via Phabricator via llvm-commits]

luismarques created this revision.
luismarques added reviewers: asb, lenary.
Herald added subscribers: llvm-commits, apazos, sameer.abuasal, pzheng, s.egerton, benna, psnobl, jocewei, PkmX, rkruppe, the_o, brucehoult, MartinMosbeck, rogfer01, edward-jones, zzheng, MaskRay, jrtc27, shiva0217, kito-cheng, niosHD, sabuasal, simoncook, johnrusso, rbar, hiraditya.
Herald added a project: LLVM.

Instead of crashing due to the `llvm_unreachable`, provide a proper error when invalid fixups/relocs are encountered.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D71536

Files:
  llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp
  llvm/test/MC/RISCV/fixups-invalid.s


Index: llvm/test/MC/RISCV/fixups-invalid.s
===================================================================
--- /dev/null
+++ llvm/test/MC/RISCV/fixups-invalid.s
@@ -0,0 +1,10 @@
+# RUN: not llvm-mc -filetype=obj %s -triple=riscv32 -o /dev/null 2>&1 \
+# RUN:     | FileCheck %s
+
+.byte foo
+# CHECK: error: 1-byte data relocations not supported
+# CHECK-NEXT: foo
+
+.2byte bar
+# CHECK: error: 2-byte data relocations not supported
+# CHECK-NEXT: bar
Index: llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp
===================================================================
--- llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp
+++ llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp
@@ -9,6 +9,7 @@
 #include "MCTargetDesc/RISCVFixupKinds.h"
 #include "MCTargetDesc/RISCVMCExpr.h"
 #include "MCTargetDesc/RISCVMCTargetDesc.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCELFObjectWriter.h"
 #include "llvm/MC/MCFixup.h"
 #include "llvm/MC/MCObjectWriter.h"
@@ -54,7 +55,8 @@
   if (IsPCRel) {
     switch (Kind) {
     default:
-      llvm_unreachable("invalid fixup kind!");
+      Ctx.reportError(Fixup.getLoc(), "Unsupported relocation type");
+      return ELF::R_RISCV_NONE;
     case FK_Data_4:
     case FK_PCRel_4:
       return ELF::R_RISCV_32_PCREL;
@@ -87,7 +89,14 @@
 
   switch (Kind) {
   default:
-    llvm_unreachable("invalid fixup kind!");
+    Ctx.reportError(Fixup.getLoc(), "Unsupported relocation type");
+    return ELF::R_RISCV_NONE;
+  case FK_Data_1:
+    Ctx.reportError(Fixup.getLoc(), "1-byte data relocations not supported");
+    return ELF::R_RISCV_NONE;
+  case FK_Data_2:
+    Ctx.reportError(Fixup.getLoc(), "2-byte data relocations not supported");
+    return ELF::R_RISCV_NONE;
   case FK_Data_4:
     if (Expr->getKind() == MCExpr::Target &&
         cast<RISCVMCExpr>(Expr)->getKind() == RISCVMCExpr::VK_RISCV_32_PCREL)


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