Fix DIStringType length emitting in DWARF

For some cases, there wasn't DW_AT_string_length added to
variable, which resulted in treating vla array as character.

Author: MiloszSkobejko

IGC/DebugInfo/DwarfCompileUnit.cpp

@@ -2034,11 +2034,18 @@ void CompileUnit::constructContainingTypeDIEs() {
   }
 }
 
-IGC::DIE *CompileUnit::constructVariableDIE(DbgVariable &DV, bool isScopeAbstract) {
+IGC::DIE *CompileUnit::constructVariableDIE(DbgVariable &DV) {
   StringRef Name = DV.getName();
   LLVM_DEBUG(dbgs() << "[DwarfDebug] constructing DIE for variable <" << Name << ">\n");
   // Define variable debug information entry.
   DIE *VariableDie = new DIE(DV.getTag());
+  insertDIE(const_cast<DILocalVariable *>(DV.getVariable()), VariableDie);
+  return VariableDie;
+}
+
+void CompileUnit::applyVariableAttributes(DbgVariable &DV, DIE *VariableDie, bool isScopeAbstract) {
+  StringRef Name = DV.getName();
+  LLVM_DEBUG(dbgs() << "[DwarfDebug] applying attributes for DIE variable <" << Name << ">\n");
   DbgVariable *AbsVar = DV.getAbstractVariable();
   DIE *AbsDIE = AbsVar ? AbsVar->getDIE() : NULL;
   if (AbsDIE) {
@@ -2058,7 +2065,7 @@ IGC::DIE *CompileUnit::constructVariableDIE(DbgVariable &DV, bool isScopeAbstrac
   if (isScopeAbstract) {
     DV.setDIE(VariableDie);
     LLVM_DEBUG(dbgs() << "  done. Variable is scope-abstract\n");
-    return VariableDie;
+    return;
   }
 
   // Add variable address.
@@ -2079,21 +2086,20 @@ IGC::DIE *CompileUnit::constructVariableDIE(DbgVariable &DV, bool isScopeAbstrac
 
     DV.setDIE(VariableDie);
     LLVM_DEBUG(dbgs() << "  done. Location is taken from .debug_loc\n");
-    return VariableDie;
+    return;
   }
 
   // Check if variable is described by a DBG_VALUE instruction.
   const Instruction *pDbgInst = DV.getDbgInst();
   if (!pDbgInst || !DV.currentLocationIsInlined()) {
     DV.setDIE(VariableDie);
     LLVM_DEBUG(dbgs() << " done. No dbg.inst assotiated\n");
-    return VariableDie;
+    return;
   }
 
   buildLocation(pDbgInst, DV, VariableDie);
 
   LLVM_DEBUG(dbgs() << " done. Location is emitted directly in DIE\n");
-  return VariableDie;
 }
 
 void CompileUnit::buildLocation(const llvm::Instruction *pDbgInst, DbgVariable &DV, IGC::DIE *VariableDie) {

IGC/DebugInfo/DwarfCompileUnit.hpp

@@ -355,7 +355,10 @@ class CompileUnit {
   void constructContainingTypeDIEs();
 
   /// constructVariableDIE - Construct a DIE for the given DbgVariable.
-  DIE *constructVariableDIE(DbgVariable &DV, bool isScopeAbstract);
+  DIE *constructVariableDIE(DbgVariable &DV);
+
+  /// Apply attributes for DIE created in constructVariableDIE
+  void applyVariableAttributes(DbgVariable &DV, DIE *VariableDie, bool isScopeAbstract);
 
   /// Create a DIE with the given Tag, add the DIE to its parent, and
   /// call insertDIE if MD is not null.

IGC/DebugInfo/DwarfDebug.cpp

@@ -682,7 +682,6 @@ DIE *DwarfDebug::createScopeChildrenDIE(CompileUnit *TheCU, LexicalScope *Scope,
   DIE *ObjectPointer = NULL;
 
   SmallVector<DbgVariable *, 8> dbgVariables;
-
   // Collect arguments for current function.
   if (LScopes.isCurrentFunctionScope(Scope)) {
     std::copy(CurrentFnArguments.begin(), CurrentFnArguments.end(), std::back_inserter(dbgVariables));
@@ -694,15 +693,23 @@ DIE *DwarfDebug::createScopeChildrenDIE(CompileUnit *TheCU, LexicalScope *Scope,
     std::copy(Variables.begin(), Variables.end(), std::back_inserter(dbgVariables));
   }
 
-  // Collect all argument/variable children
+  // Create and collect all argument/variable children
   for (DbgVariable *ArgDV : dbgVariables) {
     if (!ArgDV)
       continue;
-    if (DIE *Arg = TheCU->constructVariableDIE(*ArgDV, Scope->isAbstractScope())) {
-      Children.push_back(Arg);
-      if (ArgDV->isObjectPointer())
-        ObjectPointer = Arg;
-    }
+    DIE *Arg = TheCU->constructVariableDIE(*ArgDV);
+    Children.push_back(Arg);
+    if (ArgDV->isObjectPointer())
+      ObjectPointer = Arg;
+  }
+
+  // Apply attributes to each created DIE. It needs to be done after creating all
+  // subprogram DIEs, beacuse we might need reference to them in addType() function.
+  for (DbgVariable *ArgDV : dbgVariables) {
+    if (!ArgDV)
+      continue;
+    DIE *VarDIE = TheCU->getDIE(const_cast<DILocalVariable*>(ArgDV->getVariable()));
+    TheCU->applyVariableAttributes(*ArgDV, VarDIE, Scope->isAbstractScope());
   }
 
   // There is no need to emit empty lexical block DIE.
@@ -1135,9 +1142,9 @@ void DwarfDebug::collectDeadVariables() {
         if (!isa<DILocalVariable>(DV))
           continue;
         DbgVariable NewVar(cast<DILocalVariable>(DV));
-        if (DIE *VariableDIE = SPCU->constructVariableDIE(NewVar, false)) {
-          SPDIE->addChild(VariableDIE);
-        }
+        DIE *VariableDIE = SPCU->constructVariableDIE(NewVar);
+        SPCU->applyVariableAttributes(NewVar, VariableDIE, false);
+        SPDIE->addChild(VariableDIE);
       }
     }