[llvm] cc61283 - [DebugInfo] Avoid crashing on an invalid section identifier.

[Igor Kudrin via llvm-commits]

Author: Igor Kudrin
Date: 2020-03-05T10:54:43+07:00
New Revision: cc61283bf6c4cb88d23c6cbdb58b8c7481709b7e

URL: https://github.com/llvm/llvm-project/commit/cc61283bf6c4cb88d23c6cbdb58b8c7481709b7e
DIFF: https://github.com/llvm/llvm-project/commit/cc61283bf6c4cb88d23c6cbdb58b8c7481709b7e.diff

LOG: [DebugInfo] Avoid crashing on an invalid section identifier.

A DWARFSectionKind is read from input. It is not validated on parsing,
so an unexpected value may result in reaching llvm_unreachable() in
DWARFUnitIndex::getColumnHeader() when dumping the index section.

Differential Revision: https://reviews.llvm.org/D75609

Added: 
    llvm/test/DebugInfo/X86/debug-cu-index-unknown-section.s

Modified: 
    llvm/lib/DebugInfo/DWARF/DWARFUnitIndex.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/DebugInfo/DWARF/DWARFUnitIndex.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnitIndex.cpp
index f29c1e6cc5c7..91b561993ad9 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFUnitIndex.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFUnitIndex.cpp
@@ -118,7 +118,7 @@ StringRef DWARFUnitIndex::getColumnHeader(DWARFSectionKind DS) {
     CASE(MACINFO);
     CASE(MACRO);
   }
-  llvm_unreachable("unknown DWARFSectionKind");
+  return "<unknown>";
 }
 
 void DWARFUnitIndex::dump(raw_ostream &OS) const {

diff  --git a/llvm/test/DebugInfo/X86/debug-cu-index-unknown-section.s b/llvm/test/DebugInfo/X86/debug-cu-index-unknown-section.s
new file mode 100644
index 000000000000..05b202a32547
--- /dev/null
+++ b/llvm/test/DebugInfo/X86/debug-cu-index-unknown-section.s
@@ -0,0 +1,33 @@
+# RUN: llvm-mc -triple x86_64-unknown-linux %s -filetype=obj -o - | \
+# RUN:   llvm-dwarfdump -debug-cu-index - | \
+# RUN:   FileCheck %s
+
+# CHECK:      .debug_cu_index contents:
+# CHECK-NEXT: version = 2 slots = 2
+# CHECK-EMPTY:
+# CHECK-NEXT: Index Signature          INFO                     <unknown>
+# CHECK-NEXT: ----- ------------------ ------------------------ ------------------------
+# CHECK-NEXT:     1 0x1100001122222222 [0x00001000, 0x00001010) [0x00002000, 0x00002020)
+
+    .section .debug_cu_index, "", @progbits
+## Header:
+    .long 2             # Version
+    .long 2             # Section count
+    .long 1             # Unit count
+    .long 2             # Slot count
+## Hash Table of Signatures:
+    .quad 0x1100001122222222
+    .quad 0
+## Parallel Table of Indexes:
+    .long 1
+    .long 0
+## Table of Section Offsets:
+## Row 0:
+    .long 1             # DW_SECT_INFO
+    .long 9             # Invalid section identifier
+# Row 1:
+    .long 0x1000        # Offset in .debug_info.dwo
+    .long 0x2000
+## Table of Section Sizes:
+    .long 0x10          # Size in .debug_info.dwo
+    .long 0x20