1 files changed, 46 insertions, 34 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index ee14423ca3d0..047676d4c11e 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -480,7 +480,7 @@ static bool hasObjCCategory(StringRef Name) {
   if (!isObjCClass(Name))
     return false;
 
-  return Name.find(") ") != StringRef::npos;
+  return Name.contains(") ");
 }
 
 static void getObjCClassCategory(StringRef In, StringRef &Class,
@@ -587,14 +587,6 @@ void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &SrcCU,
   }
 }
 
-DIE &DwarfDebug::constructSubprogramDefinitionDIE(const DISubprogram *SP) {
-  DICompileUnit *Unit = SP->getUnit();
-  assert(SP->isDefinition() && "Subprogram not a definition");
-  assert(Unit && "Subprogram definition without parent unit");
-  auto &CU = getOrCreateDwarfCompileUnit(Unit);
-  return *CU.getOrCreateSubprogramDIE(SP);
-}
-
 /// Represents a parameter whose call site value can be described by applying a
 /// debug expression to a register in the forwarded register worklist.
 struct FwdRegParamInfo {
@@ -945,7 +937,7 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
         continue;
 
       unsigned CallReg = 0;
-      DIE *CalleeDIE = nullptr;
+      const DISubprogram *CalleeSP = nullptr;
       const Function *CalleeDecl = nullptr;
       if (CalleeOp.isReg()) {
         CallReg = CalleeOp.getReg();
@@ -955,19 +947,7 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
         CalleeDecl = dyn_cast<Function>(CalleeOp.getGlobal());
         if (!CalleeDecl || !CalleeDecl->getSubprogram())
           continue;
-        const DISubprogram *CalleeSP = CalleeDecl->getSubprogram();
-
-        if (CalleeSP->isDefinition()) {
-          // Ensure that a subprogram DIE for the callee is available in the
-          // appropriate CU.
-          CalleeDIE = &constructSubprogramDefinitionDIE(CalleeSP);
-        } else {
-          // Create the declaration DIE if it is missing. This is required to
-          // support compilation of old bitcode with an incomplete list of
-          // retained metadata.
-          CalleeDIE = CU.getOrCreateSubprogramDIE(CalleeSP);
-        }
-        assert(CalleeDIE && "Must have a DIE for the callee");
+        CalleeSP = CalleeDecl->getSubprogram();
       }
 
       // TODO: Omit call site entries for runtime calls (objc_msgSend, etc).
@@ -1004,7 +984,7 @@ void DwarfDebug::constructCallSiteEntryDIEs(const DISubprogram &SP,
                         << (IsTail ? " [IsTail]" : "") << "\n");
 
       DIE &CallSiteDIE = CU.constructCallSiteEntryDIE(
-          ScopeDIE, CalleeDIE, IsTail, PCAddr, CallAddr, CallReg);
+          ScopeDIE, CalleeSP, IsTail, PCAddr, CallAddr, CallReg);
 
       // Optionally emit call-site-param debug info.
       if (emitDebugEntryValues()) {
@@ -1427,6 +1407,10 @@ void DwarfDebug::finalizeModuleInfo() {
 
 // Emit all Dwarf sections that should come after the content.
 void DwarfDebug::endModule() {
+  // Terminate the pending line table.
+  if (PrevCU)
+    terminateLineTable(PrevCU);
+  PrevCU = nullptr;
   assert(CurFn == nullptr);
   assert(CurMI == nullptr);
 
@@ -2102,12 +2086,22 @@ void DwarfDebug::beginInstruction(const MachineInstr *MI) {
 static DebugLoc findPrologueEndLoc(const MachineFunction *MF) {
   // First known non-DBG_VALUE and non-frame setup location marks
   // the beginning of the function body.
-  for (const auto &MBB : *MF)
-    for (const auto &MI : MBB)
+  DebugLoc LineZeroLoc;
+  for (const auto &MBB : *MF) {
+    for (const auto &MI : MBB) {
       if (!MI.isMetaInstruction() && !MI.getFlag(MachineInstr::FrameSetup) &&
-          MI.getDebugLoc())
-        return MI.getDebugLoc();
-  return DebugLoc();
+          MI.getDebugLoc()) {
+        // Scan forward to try to find a non-zero line number. The prologue_end
+        // marks the first breakpoint in the function after the frame setup, and
+        // a compiler-generated line 0 location is not a meaningful breakpoint.
+        // If none is found, return the first location after the frame setup.
+        if (MI.getDebugLoc().getLine())
+          return MI.getDebugLoc();
+        LineZeroLoc = MI.getDebugLoc();
+      }
+    }
+  }
+  return LineZeroLoc;
 }
 
 /// Register a source line with debug info. Returns the  unique label that was
@@ -2162,24 +2156,42 @@ void DwarfDebug::beginFunctionImpl(const MachineFunction *MF) {
 
   DwarfCompileUnit &CU = getOrCreateDwarfCompileUnit(SP->getUnit());
 
+  Asm->OutStreamer->getContext().setDwarfCompileUnitID(
+      getDwarfCompileUnitIDForLineTable(CU));
+
+  // Record beginning of function.
+  PrologEndLoc = emitInitialLocDirective(
+      *MF, Asm->OutStreamer->getContext().getDwarfCompileUnitID());
+}
+
+unsigned
+DwarfDebug::getDwarfCompileUnitIDForLineTable(const DwarfCompileUnit &CU) {
   // Set DwarfDwarfCompileUnitID in MCContext to the Compile Unit this function
   // belongs to so that we add to the correct per-cu line table in the
   // non-asm case.
   if (Asm->OutStreamer->hasRawTextSupport())
     // Use a single line table if we are generating assembly.
-    Asm->OutStreamer->getContext().setDwarfCompileUnitID(0);
+    return 0;
   else
-    Asm->OutStreamer->getContext().setDwarfCompileUnitID(CU.getUniqueID());
+    return CU.getUniqueID();
+}
 
-  // Record beginning of function.
-  PrologEndLoc = emitInitialLocDirective(
-      *MF, Asm->OutStreamer->getContext().getDwarfCompileUnitID());
+void DwarfDebug::terminateLineTable(const DwarfCompileUnit *CU) {
+  const auto &CURanges = CU->getRanges();
+  auto &LineTable = Asm->OutStreamer->getContext().getMCDwarfLineTable(
+      getDwarfCompileUnitIDForLineTable(*CU));
+  // Add the last range label for the given CU.
+  LineTable.getMCLineSections().addEndEntry(
+      const_cast<MCSymbol *>(CURanges.back().End));
 }
 
 void DwarfDebug::skippedNonDebugFunction() {
   // If we don't have a subprogram for this function then there will be a hole
   // in the range information. Keep note of this by setting the previously used
   // section to nullptr.
+  // Terminate the pending line table.
+  if (PrevCU)
+    terminateLineTable(PrevCU);
   PrevCU = nullptr;
   CurFn = nullptr;
 }