[PATCH] D75188: [NFC][DebugInfo] Refactor address advancing operations to share code

[James Henderson via Phabricator via llvm-commits]

jhenderson created this revision.
jhenderson added reviewers: labath, ikudrin, JDevlieghere, dblaikie, probinson.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.
jhenderson added a child revision: D74819: [DebugInfo] Report unsupported maximum_operations_per_instruction values.

On its own, this change won't achieve much, but it provides a good place to do extra error checks that I plan on adding in D43470 <https://reviews.llvm.org/D43470>, D74819 <https://reviews.llvm.org/D74819> and another TBD patch. See the full patch series for context.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D75188

Files:
  llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp


Index: llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
===================================================================
--- llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ llvm/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -569,6 +569,24 @@
   return LT;
 }
 
+struct AdvanceAddrProperties {
+  uint8_t AdjustedOpcode;
+  uint8_t OperationAdvance;
+};
+
+static AdvanceAddrProperties
+getOperationAdvance(uint8_t Opcode, uint8_t OpcodeBase, uint8_t LineRange) {
+  AdvanceAddrProperties Result;
+  Result.AdjustedOpcode = Opcode - OpcodeBase;
+  Result.OperationAdvance = Result.AdjustedOpcode / LineRange;
+  return Result;
+}
+
+static uint64_t advanceAddr(uint64_t OperationAdvance,
+                            const DWARFDebugLine::Prologue &Prologue) {
+  return OperationAdvance * Prologue.MinInstLength;
+}
+
 Error DWARFDebugLine::LineTable::parse(
     DWARFDataExtractor &DebugLineData, uint64_t *OffsetPtr,
     const DWARFContext &Ctx, const DWARFUnit *U,
@@ -796,7 +814,7 @@
         // result to the address register of the state machine.
         {
           uint64_t AddrOffset =
-              DebugLineData.getULEB128(OffsetPtr) * Prologue.MinInstLength;
+              advanceAddr(DebugLineData.getULEB128(OffsetPtr), Prologue);
           State.Row.Address.Address += AddrOffset;
           if (OS)
             *OS << " (" << AddrOffset << ")";
@@ -852,13 +870,13 @@
         // than twice that range will it need to use both DW_LNS_advance_pc
         // and a special opcode, requiring three or more bytes.
         {
-          uint8_t AdjustOpcode = 255 - Prologue.OpcodeBase;
+          AdvanceAddrProperties AdvanceAddr =
+              getOperationAdvance(255, Prologue.OpcodeBase, Prologue.LineRange);
           uint64_t AddrOffset =
-              (AdjustOpcode / Prologue.LineRange) * Prologue.MinInstLength;
+              advanceAddr(AdvanceAddr.OperationAdvance, Prologue);
           State.Row.Address.Address += AddrOffset;
           if (OS)
-            *OS
-                << format(" (0x%16.16" PRIx64 ")", AddrOffset);
+            *OS << format(" (0x%16.16" PRIx64 ")", AddrOffset);
         }
         break;
 
@@ -951,11 +969,11 @@
       //
       // line increment = line_base + (adjusted opcode % line_range)
 
-      uint8_t AdjustOpcode = Opcode - Prologue.OpcodeBase;
-      uint64_t AddrOffset =
-          (AdjustOpcode / Prologue.LineRange) * Prologue.MinInstLength;
+      AdvanceAddrProperties AdvanceAddr =
+          getOperationAdvance(Opcode, Prologue.OpcodeBase, Prologue.LineRange);
+      uint64_t AddrOffset = advanceAddr(AdvanceAddr.OperationAdvance, Prologue);
       int32_t LineOffset =
-          Prologue.LineBase + (AdjustOpcode % Prologue.LineRange);
+          Prologue.LineBase + (AdvanceAddr.AdjustedOpcode % Prologue.LineRange);
       State.Row.Line += LineOffset;
       State.Row.Address.Address += AddrOffset;
 


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