Make a DWARFDIE class that can help avoid using the wrong DWARFUnit when extracting attributes

Many places pass around a DWARFDebugInfoEntryMinimal and a DWARFUnit. It is easy to get things wrong by using the wrong DWARFUnit with a DWARFDebugInfoEntryMinimal. This patch creates a DWARFDie class that contains the DWARFUnit and DWARFDebugInfoEntryMinimal objects so that they can't get out of sync. All attribute extraction has been moved out of DWARFDebugInfoEntryMinimal and into DWARFDie. DWARFDebugInfoEntryMinimal was also renamed to DWARFDebugInfoEntry.

DWARFDie objects are temporary objects that are used by clients and contain 2 pointers that you always need to have anyway. Keeping them grouped will avoid errors and simplify many of the attribute extracting APIs by not having to pass in a DWARFUnit.

Differential Revision: https://reviews.llvm.org/D27634

llvm-svn: 289565

1 files changed, 19 insertions, 23 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index adcbff78d1c..5982fbbab24 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -156,11 +156,11 @@ void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType, bool DumpEH,
     OS << "\n.debug_line contents:\n";
     for (const auto &CU : compile_units()) {
       savedAddressByteSize = CU->getAddressByteSize();
-      const auto *CUDIE = CU->getUnitDIE();
-      if (CUDIE == nullptr)
+      auto CUDIE = CU->getUnitDIE();
+      if (!CUDIE)
         continue;
-      unsigned stmtOffset = CUDIE->getAttributeValueAsSectionOffset(
-          CU.get(), DW_AT_stmt_list, -1U);
+      unsigned stmtOffset = CUDIE.getAttributeValueAsSectionOffset(
+          DW_AT_stmt_list, -1U);
       if (stmtOffset != -1U) {
         DataExtractor lineData(getLineSection().Data, isLittleEndian(),
                                savedAddressByteSize);
@@ -412,12 +412,12 @@ DWARFContext::getLineTableForUnit(DWARFUnit *U) {
   if (!Line)
     Line.reset(new DWARFDebugLine(&getLineSection().Relocs));
 
-  const auto *UnitDIE = U->getUnitDIE();
-  if (UnitDIE == nullptr)
+  auto UnitDIE = U->getUnitDIE();
+  if (!UnitDIE)
     return nullptr;
 
   unsigned stmtOffset =
-      UnitDIE->getAttributeValueAsSectionOffset(U, DW_AT_stmt_list, -1U);
+      UnitDIE.getAttributeValueAsSectionOffset(DW_AT_stmt_list, -1U);
   if (stmtOffset == -1U)
     return nullptr; // No line table for this compile unit.
 
@@ -477,14 +477,12 @@ static bool getFunctionNameForAddress(DWARFCompileUnit *CU, uint64_t Address,
     return false;
   // The address may correspond to instruction in some inlined function,
   // so we have to build the chain of inlined functions and take the
-  // name of the topmost function in it.
-  const DWARFDebugInfoEntryInlinedChain &InlinedChain =
-      CU->getInlinedChainForAddress(Address);
-  if (InlinedChain.DIEs.size() == 0)
+  // name of the topmost function in it.SmallVectorImpl<DWARFDie> &InlinedChain
+  SmallVector<DWARFDie, 4> InlinedChain;
+  CU->getInlinedChainForAddress(Address, InlinedChain);
+  if (InlinedChain.size() == 0)
     return false;
-  const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain.DIEs[0];
-  if (const char *Name =
-          TopFunctionDIE.getSubroutineName(InlinedChain.U, Kind)) {
+  if (const char *Name = InlinedChain[0].getSubroutineName(Kind)) {
     FunctionName = Name;
     return true;
   }
@@ -559,9 +557,9 @@ DWARFContext::getInliningInfoForAddress(uint64_t Address,
     return InliningInfo;
 
   const DWARFLineTable *LineTable = nullptr;
-  const DWARFDebugInfoEntryInlinedChain &InlinedChain =
-      CU->getInlinedChainForAddress(Address);
-  if (InlinedChain.DIEs.size() == 0) {
+  SmallVector<DWARFDie, 4> InlinedChain;
+  CU->getInlinedChainForAddress(Address, InlinedChain);
+  if (InlinedChain.size() == 0) {
     // If there is no DIE for address (e.g. it is in unavailable .dwo file),
     // try to at least get file/line info from symbol table.
     if (Spec.FLIKind != FileLineInfoKind::None) {
@@ -576,12 +574,11 @@ DWARFContext::getInliningInfoForAddress(uint64_t Address,
   }
 
   uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
-  for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) {
-    const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i];
+  for (uint32_t i = 0, n = InlinedChain.size(); i != n; i++) {
+    DWARFDie &FunctionDIE = InlinedChain[i];
     DILineInfo Frame;
     // Get function name if necessary.
-    if (const char *Name =
-            FunctionDIE.getSubroutineName(InlinedChain.U, Spec.FNKind))
+    if (const char *Name = FunctionDIE.getSubroutineName(Spec.FNKind))
       Frame.FunctionName = Name;
     if (Spec.FLIKind != FileLineInfoKind::None) {
       if (i == 0) {
@@ -603,8 +600,7 @@ DWARFContext::getInliningInfoForAddress(uint64_t Address,
       }
       // Get call file/line/column of a current DIE.
       if (i + 1 < n) {
-        FunctionDIE.getCallerFrame(InlinedChain.U, CallFile, CallLine,
-                                   CallColumn);
+        FunctionDIE.getCallerFrame(CallFile, CallLine, CallColumn);
       }
     }
     InliningInfo.addFrame(Frame);