Fix segfault in AArch64 backend with -g and -mbig-endian

Fix a null pointer dereference when trying to swap the endianness of
fixups in the .eh_frame section in the AArch64 backend.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218311 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp b/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
index 260c7fd5c4fe764f1351328ace43b37059199a02..0bc2f777d25a8a9f460b173a9291d8ef2557cc66 100644 (file)
--- a/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
+++ b/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
@@ -535,8 +535,8 @@ void ELFAArch64AsmBackend::applyFixup(const MCFixup &Fixup, char *Data,
   // store fixups in .eh_frame section in big endian order
   if (!IsLittleEndian && Fixup.getKind() == FK_Data_4) {
     const MCSection *Sec = Fixup.getValue()->FindAssociatedSection();
-    const MCSectionELF *SecELF = static_cast<const MCSectionELF *>(Sec);
-    if (SecELF->getSectionName() == ".eh_frame")
+    const MCSectionELF *SecELF = dyn_cast_or_null<const MCSectionELF>(Sec);
+    if (SecELF && SecELF->getSectionName() == ".eh_frame")
       Value = ByteSwap_32(unsigned(Value));
   }
   AArch64AsmBackend::applyFixup (Fixup, Data, DataSize, Value, IsPCRel);

diff --git a/test/DebugInfo/AArch64/big-endian.ll b/test/DebugInfo/AArch64/big-endian.ll
new file mode 100644 (file)
index 0000000..15699e0
--- /dev/null
+++ b/test/DebugInfo/AArch64/big-endian.ll
@@ -0,0 +1,22 @@
+; RUN: llc %s -filetype=asm -o -
+
+target datalayout = "E-m:e-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64_be--none-eabi"
+
+@a = common global i32 0, align 4
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!8, !9}
+!llvm.ident = !{!10}
+
+!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.6.0 ", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !2, metadata !3, metadata !2, metadata !"", i32 1} ; [ DW_TAG_compile_unit ] [/work/validation/-] [DW_LANG_C99]
+!1 = metadata !{metadata !"-", metadata !"/work/validation"}
+!2 = metadata !{}
+!3 = metadata !{metadata !4}
+!4 = metadata !{i32 786484, i32 0, null, metadata !"a", metadata !"a", metadata !"", metadata !5, i32 1, metadata !7, i32 0, i32 1, i32* @a, null} ; [ DW_TAG_variable ] [a] [line 1] [def]
+!5 = metadata !{i32 786473, metadata !6}          ; [ DW_TAG_file_type ] [/work/validation/<stdin>]
+!6 = metadata !{metadata !"<stdin>", metadata !"/work/validation"}
+!7 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!8 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
+!9 = metadata !{i32 2, metadata !"Debug Info Version", i32 1}
+!10 = metadata !{metadata !"clang version 3.6.0 "}