Use DWARFDataExtractor::getInitialLength in DWARFDebugAddr

[probinson]

LGTM aside from the possible clang-format nit.

llvm/lib/DebugInfo/DWARF/DWARFDebugAddr.cpp

54

clang-format complains; is there an indentation issue here?

[labath]

fix formatting

llvm/lib/DebugInfo/DWARF/DWARFDebugAddr.cpp

while (Count--)
     Addrs.push_back(Data.getRelocatedValue(AddrSize, OffsetPtr));
   return Error::success();
 }
 
 Error DWARFDebugAddrTable::extractV5(const DWARFDataExtractor &Data,
                                      uint64_t *OffsetPtr, uint8_t CUAddrSize,
                                      std::function<void(Error)> WarnCallback) {
   Offset = *OffsetPtr;
-  // Check that we can read the unit length field.
-  if (!Data.isValidOffsetForDataOfSize(Offset, 4))
-    return createStringError(errc::invalid_argument,
-                             "section is not large enough to contain an "
-                             "address table length at offset 0x%" PRIx64,
-                             Offset);
-  Format = dwarf::DwarfFormat::DWARF32;
-  Length = Data.getU32(OffsetPtr);
-  if (Length == dwarf::DW_LENGTH_DWARF64) {
-    // Check that we can read the extended unit length field.
-    if (!Data.isValidOffsetForDataOfSize(*OffsetPtr, 8)) {
-      invalidateLength();
-      return createStringError(
-          errc::invalid_argument,
-          "section is not large enough to contain an extended length field "
-          "of the address table at offset 0x%" PRIx64,
-          Offset);
-    }
-    Format = dwarf::DwarfFormat::DWARF64;
-    Length = Data.getU64(OffsetPtr);
-  } else if (Length >= dwarf::DW_LENGTH_lo_reserved) {
-    uint64_t DiagnosticLength = Length;
+  llvm::Error Err = Error::success();
+  std::tie(Length, Format) = Data.getInitialLength(OffsetPtr, &Err);
+  if (Err) {
     invalidateLength();
-    return createStringError(
-        errc::not_supported,
-        "address table at offset 0x%" PRIx64
-        " has unsupported reserved unit length of value 0x%" PRIx64,
-        Offset, DiagnosticLength);
+    return createStringError(errc::invalid_argument,
+                             "parsing address table at offset 0x%" PRIx64
+                             ": %s",
+                             Offset, toString(std::move(Err)).c_str());
   }
 
   if (!Data.isValidOffsetForDataOfSize(*OffsetPtr, Length)) {
     uint64_t DiagnosticLength = Length;
     invalidateLength();
     return createStringError(
         errc::invalid_argument,
         "section is not large enough to contain an address table "

llvm/test/tools/llvm-dwarfdump/X86/debug_addr_reserved_length.s

 # RUN: llvm-mc %s -filetype obj -triple x86_64-pc-linux -o - | \
 # RUN:   llvm-dwarfdump --debug-addr - 2>&1 | \
 # RUN:   FileCheck %s --implicit-check-not=error
 
-# CHECK: error: address table at offset 0x0 has unsupported reserved unit length of value 0xfffffff0
+# CHECK: error: parsing address table at offset 0x0: unsupported reserved unit length of value 0xfffffff0
 
 .section .debug_addr,"",@progbits
 .long 0xfffffff0

llvm/test/tools/llvm-dwarfdump/X86/debug_addr_too_small_for_extended_length_field.s

 # RUN: llvm-mc %s -filetype obj -triple i386-pc-linux -o - | \
 # RUN: llvm-dwarfdump -debug-addr - 2> %t.err | FileCheck %s
 # RUN: FileCheck %s -input-file %t.err -check-prefix=ERR
 
 # CHECK: .debug_addr contents:
 # CHECK-NOT: {{.}}
-# ERR: section is not large enough to contain an extended length field of the address table at offset 0x0
+# ERR: parsing address table at offset 0x0: unexpected end of data at offset 0x4
 # ERR-NOT: {{.}}
 
 # too small section to contain an extended length field of a DWARF64 address table.
   .section  .debug_addr,"",@progbits
   .long 0xffffffff      # DWARF64 mark
   .space 7              # a DWARF64 unit length field takes 8 bytes.

llvm/test/tools/llvm-dwarfdump/X86/debug_addr_too_small_for_length_field.s

 # RUN: llvm-mc %s -filetype obj -triple i386-pc-linux -o - | \
 # RUN: llvm-dwarfdump -debug-addr - 2> %t.err | FileCheck %s
 # RUN: FileCheck %s -input-file %t.err -check-prefix=ERR
 
 # CHECK: .debug_addr contents:
 # CHECK-NOT: {{.}}
-# ERR: section is not large enough to contain an address table length at offset 0x0
+# ERR: parsing address table at offset 0x0: unexpected end of data at offset 0x0
 # ERR-NOT: {{.}}
 
 # too small section to contain length field
   .section  .debug_addr,"",@progbits
 .Ldebug_addr0:
   .short 1 # unit_length