[DWARF] Set discriminator to 0 for DW_LNS_copy

Summary:
Make DW_LNS_copy set the discriminator register to 0, to conform to
DWARF 4 & 5: "Then it sets the discriminator register to 0, and sets the
basic_block, prologue_end and epilogue_begin registers to false."

Because all of DW_LNE_end_sequence, DN_LNS_copy, and special opcodes reset
discriminator to 0, we can move discriminator=0 to appendRowToMatrix.

Also, make DW_LNS_copy print before appending the row, as it is similar
to a address+=0,line+=0 special opcode, which prints before appending
the row.

Reviewers: dblaikie, probinson, aprantl

Reviewed By: dblaikie

Subscribers: danielcdh, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60364

llvm-svn: 358148

1 files changed, 3 insertions, 5 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
index 9a720651ebb..8299be38ac6 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -347,6 +347,7 @@ Error DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
 DWARFDebugLine::Row::Row(bool DefaultIsStmt) { reset(DefaultIsStmt); }
 
 void DWARFDebugLine::Row::postAppend() {
+  Discriminator = 0;
   BasicBlock = false;
   PrologueEnd = false;
   EpilogueBegin = false;
@@ -640,15 +641,14 @@ Error DWARFDebugLine::LineTable::parse(
       // Standard Opcodes
       case DW_LNS_copy:
         // Takes no arguments. Append a row to the matrix using the
-        // current values of the state-machine registers. Then set
-        // the basic_block register to false.
-        State.appendRowToMatrix();
+        // current values of the state-machine registers.
         if (OS) {
           *OS << "\n";
           OS->indent(12);
           State.Row.dump(*OS);
           *OS << "\n";
         }
+        State.appendRowToMatrix();
         break;
 
       case DW_LNS_advance_pc:
@@ -828,8 +828,6 @@ Error DWARFDebugLine::LineTable::parse(
       }
 
       State.appendRowToMatrix();
-      // Reset discriminator to 0.
-      State.Row.Discriminator = 0;
     }
     if(OS)
       *OS << "\n";