[PATCH] D123877: [BPF] Emit fatal error if out of range for FK_PCRel_2 branch target

[Yonghong Song via Phabricator via llvm-commits]

yonghong-song updated this revision to Diff 423720.
yonghong-song retitled this revision from "[BPF] Add assert for the range of FK_PCRel_2 branch target" to "[BPF] Emit fatal error if out of range for FK_PCRel_2 branch target".
yonghong-song edited the summary of this revision.
yonghong-song added a comment.

- use report_fatal_error instead of assert.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D123877/new/

https://reviews.llvm.org/D123877

Files:
  llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp


Index: llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
===================================================================
--- llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
+++ llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
@@ -87,6 +87,11 @@
     }
   } else {
     assert(Fixup.getKind() == FK_PCRel_2);
+
+    int64_t ByteOff = (int64_t)Value - 8;
+    if (ByteOff > INT16_MAX * 8 || ByteOff < INT16_MIN * 8)
+      report_fatal_error("Branch target out of insn range");
+
     Value = (uint16_t)((Value - 8) / 8);
     support::endian::write<uint16_t>(&Data[Fixup.getOffset() + 2], Value,
                                      Endian);


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