[PATCH] D98589: [llvm] [dwarf] Fix DWARFListTableHeader::getOffsetEntry off-by-one

[Jan Kratochvil via Phabricator via llvm-commits]

jankratochvil created this revision.
jankratochvil added a reviewer: dblaikie.
jankratochvil added a project: LLVM.
jankratochvil requested review of this revision.

D98289 <https://reviews.llvm.org/D98289> was erroneously reporting `invalid range list offset 0x20110` instead of `invalid range list table index 0`.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D98589

Files:
  llvm/include/llvm/DebugInfo/DWARF/DWARFListTable.h
  llvm/unittests/DebugInfo/DWARF/DWARFListTableTest.cpp


Index: llvm/unittests/DebugInfo/DWARF/DWARFListTableTest.cpp
===================================================================
--- llvm/unittests/DebugInfo/DWARF/DWARFListTableTest.cpp
+++ llvm/unittests/DebugInfo/DWARF/DWARFListTableTest.cpp
@@ -73,4 +73,30 @@
   EXPECT_EQ(Header.length(), 6u);
 }
 
+TEST(DWARFListTableHeader, OffsetEntryCount) {
+  static const char SecData[] = "\x10\x00\x00\x00" // Length
+                                "\x05\x00"         // Version
+                                "\x08"             // Address size
+                                "\x00"             // Segment selector size
+                                "\x01\x00\x00\x00" // Offset entry count
+                                "\x04\x00\x00\x00" // offset[0]
+                                "\x04"             // DW_RLE_offset_pair
+                                "\x01"             // ULEB128 starting offset
+                                "\x02"             // ULEB128 ending offset
+                                "\x00";            // DW_RLE_end_of_list
+  DWARFDataExtractor Extractor(StringRef(SecData, sizeof(SecData) - 1),
+                               /*isLittleEndian=*/true,
+                               /*AddrSize=*/4);
+  DWARFListTableHeader Header(/*SectionName=*/".debug_rnglists",
+                              /*ListTypeString=*/"range");
+  uint64_t Offset = 0;
+  EXPECT_FALSE(!!Header.extract(Extractor, &Offset));
+  Optional<uint64_t> Offset0 = Header.getOffsetEntry(Extractor, 0);
+  EXPECT_TRUE(!!Offset0);
+  EXPECT_EQ(*Offset0, uint64_t(4));
+  Optional<uint64_t> Offset1 = Header.getOffsetEntry(Extractor, 1);
+  EXPECT_FALSE(!!Offset1);
+  EXPECT_EQ(Header.length(), sizeof(SecData) - 1);
+}
+
 } // end anonymous namespace
Index: llvm/include/llvm/DebugInfo/DWARF/DWARFListTable.h
===================================================================
--- llvm/include/llvm/DebugInfo/DWARF/DWARFListTable.h
+++ llvm/include/llvm/DebugInfo/DWARF/DWARFListTable.h
@@ -113,7 +113,7 @@
   void dump(DataExtractor Data, raw_ostream &OS,
             DIDumpOptions DumpOpts = {}) const;
   Optional<uint64_t> getOffsetEntry(DataExtractor Data, uint32_t Index) const {
-    if (Index > HeaderData.OffsetEntryCount)
+    if (Index >= HeaderData.OffsetEntryCount)
       return None;
 
     return getOffsetEntry(Data, getHeaderOffset() + getHeaderSize(Format), Format, Index);


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