llvm-dwarfdump: fix the counting when printing DW_OP_entry_value

[aprantl]

Summary

The block size is in bytes, and not number of operands.

[JDevlieghere]

Nice catch!

[djtodoro]

cool, thanks!

llvm/lib/DebugInfo/DWARF/DWARFExpression.cpp

bool DWARFExpression::Operation::print(raw_ostream &OS, DIDumpOptions DumpOpts,
   }
   return true;
 }
 
 void DWARFExpression::print(raw_ostream &OS, DIDumpOptions DumpOpts,
                             const MCRegisterInfo *RegInfo, DWARFUnit *U,
                             bool IsEH) const {
   uint32_t EntryValExprSize = 0;
+  uint64_t EntryValStartOffset = 0;
   for (auto &Op : *this) {
     if (!Op.print(OS, DumpOpts, this, RegInfo, U, IsEH)) {
       uint64_t FailOffset = Op.getEndOffset();
       while (FailOffset < Data.getData().size())
         OS << format(" %02x", Data.getU8(&FailOffset));
       return;
     }
 
     if (Op.getCode() == DW_OP_entry_value ||
         Op.getCode() == DW_OP_GNU_entry_value) {
       OS << "(";
       EntryValExprSize = Op.getRawOperand(0);
+      EntryValStartOffset = Op.getEndOffset();
       continue;
     }
 
     if (EntryValExprSize) {
-      EntryValExprSize--;
+      EntryValExprSize -= Op.getEndOffset() - EntryValStartOffset;
       if (EntryValExprSize == 0)
         OS << ")";
     }
 
     if (Op.getEndOffset() < Data.getData().size())
       OS << ", ";
   }
 }

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

 # RUN: llvm-mc -triple x86_64-pc-linux %s -filetype=obj | llvm-dwarfdump - | FileCheck %s
 #
 # CHECK: DW_TAG_variable
 # CHECK-NEXT: DW_AT_name ("a")
 # CHECK-NEXT: DW_AT_location
-# CHECK-NEXT: DW_OP_entry_value(DW_OP_reg5 RDI), DW_OP_stack_value)
+# CHECK-NEXT: DW_OP_entry_value(DW_OP_breg5 RDI+0), DW_OP_stack_value)
 
   .section  .debug_str,"MS",@progbits,1
 .Linfo_producer:
   .asciz  "hand-written DWARF"
 .Lname_a:
   .asciz  "a"
 
   .section  .debug_loc,"",@progbits
 .Ldebug_loc0:
   .quad 0
   .quad 1
   .short  .Lloc0_end-.Lloc0_start # Loc expr size
 .Lloc0_start:
   .byte   163                     # DW_OP_entry_value
-  .byte 1                       # 1
-  .byte 85                      # super-register DW_OP_reg5
+  .byte 2                       # 2
+  .byte 117                     # DW_OP_breg5
+  .byte 0                       # +0
   .byte 159                     # DW_OP_stack_value
 .Lloc0_end:
   .quad 0
   .quad 0
   .section  .debug_abbrev,"",@progbits
   .byte 1                       # Abbreviation Code
   .byte 17                      # DW_TAG_compile_unit
   .byte 1                       # DW_CHILDREN_yes