[Autobackout][FunctionalRegression]Revert of change: 1fd886c: Implement DIGlobalVariable handling in DWARF part 1

Partially Implemented global variable handling in DWARF. Now
    global variables with type `DIGlobalVariable` and in global
    addrspace can be visible in debugger.

    This commit skips emmiting DW_AT_Location and DW_OP_addr.

Author: sys-igc

IGC/DebugInfo/DwarfCompileUnit.cpp

@@ -386,7 +386,7 @@ void CompileUnit::addBlock(DIE *Die, dwarf::Attribute Attribute, IGC::DIEBlock *
 /// entry.
 void CompileUnit::addSourceLine(DIE *Die, DIScope *S, unsigned Line) {
   // If the line number is 0, don't add it.
-  if (Line == 0 || !S)
+  if (Line == 0)
     return;
 
   unsigned FileID = DD->getOrCreateSourceID(S->getFilename(), S->getDirectory(), DD->getMD5AsBytes(S->getFile()),
@@ -444,16 +444,6 @@ void CompileUnit::addSourceLine(DIE *Die, DIType *Ty) {
   addSourceLine(Die, Ty, Ty->getLine());
 }
 
-/// addSourceLine - Add location information to specified debug information
-/// entry.
-void CompileUnit::addSourceLine(DIE *Die, DIGlobalVariable *GV) {
-  // Verify type.
-  if (!isa<DIGlobalVariable>(GV))
-    return;
-
-  addSourceLine(Die, GV->getScope(), GV->getLine());
-}
-
 void CompileUnit::addRegOrConst(IGC::DIEBlock *TheDie, unsigned DWReg) {
   // TODO: Confirm if this function is correctly used.
   auto DWRegEncoded = GetEncodedRegNum<RegisterNumbering::GRFBase>(DWReg);
@@ -1515,6 +1505,10 @@ void CompileUnit::constructTemplateValueParameterDIE(DIE &Buffer, DITemplateValu
 /// constructImportedEntityDIE - Create a DIE for DIImportedEntity.
 IGC::DIE *CompileUnit::constructImportedEntityDIE(DIImportedEntity *Module) {
   DINode *Entity = Module->getEntity();
+  if (auto *GV = dyn_cast<DIGlobalVariable>(Entity))
+    return nullptr; // Missing support for imported entity linked to a global
+                    // variable
+
   DIE *IMDie = new DIE(Module->getTag());
   insertDIE(Module, IMDie);
 
@@ -1527,8 +1521,9 @@ IGC::DIE *CompileUnit::constructImportedEntityDIE(DIImportedEntity *Module) {
     EntityDie = getOrCreateSubprogramDIE(SP);
   else if (auto *T = dyn_cast<DIType>(Entity))
     EntityDie = getOrCreateTypeDIE(T);
-  else if (auto *GV = dyn_cast<DIGlobalVariable>(Entity))
-    EntityDie = getOrCreateGlobalVariableDIE(GV, {});
+  // else if (auto* GV = dyn_cast<DIGlobalVariable>(Entity))  // TODO missing
+  // support
+  //    EntityDie = getOrCreateGlobalVariableDIE(GV, {});
   else
     EntityDie = getDIE(Entity);
 
@@ -1561,59 +1556,6 @@ IGC::DIE *CompileUnit::getOrCreateNameSpace(DINamespace *NS) {
   return NDie;
 }
 
-IGC::DIE *CompileUnit::getOrCreateGlobalVariableDIE(DIGlobalVariable *GV, ArrayRef<GlobalExpr> GlobalExprs) {
-  // Check for pre-existence.
-  if (DIE *Die = getDIE(GV))
-    return Die;
-
-  auto *GVContext = GV->getScope();
-  DIType *GTy = GV->getType();
-
-  DIE *ContextDIE = getOrCreateContextDIE(GVContext);
-
-  // Add to map.
-  DIE *VariableDIE = createAndAddDIE(GV->getTag(), *ContextDIE, GV);
-  DIScope *DeclContext;
-  if (auto *SDMDecl = GV->getStaticDataMemberDeclaration()) {
-    DeclContext = SDMDecl->getScope();
-    assert(SDMDecl->isStaticMember() && "Expected static member decl");
-    assert(GV->isDefinition());
-    // We need the declaration DIE that is in the static member's class.
-    DIE *VariableSpecDIE = getOrCreateStaticMemberDIE(SDMDecl);
-    addDIEEntry(VariableDIE, dwarf::DW_AT_specification, VariableSpecDIE);
-    // If the global variable's type is different from the one in the class
-    // member type, assume that it's more specific and also emit it.
-    if (GTy != SDMDecl->getBaseType())
-      addType(VariableDIE, GTy);
-  } else {
-    DeclContext = GV->getScope();
-    // Add name and type.
-    addString(VariableDIE, dwarf::DW_AT_name, GV->getDisplayName());
-    if (GTy)
-      addType(VariableDIE, GTy);
-
-    // Add scoping info.
-    if (!GV->isLocalToUnit())
-      addFlag(VariableDIE, dwarf::DW_AT_external);
-
-    // Add line number info.
-    addSourceLine(VariableDIE, GV);
-  }
-
-  if (!GV->isDefinition())
-    addFlag(VariableDIE, dwarf::DW_AT_declaration);
-
-  if (uint32_t AlignInBytes = GV->getAlignInBytes())
-    addUInt(VariableDIE, dwarf::DW_AT_alignment, dwarf::DW_FORM_udata, AlignInBytes);
-
-  if (MDTuple *TP = GV->getTemplateParams())
-    addTemplateParams(*VariableDIE, DINodeArray(TP));
-
-  // TODO: Add location and relocation entry to Global Variable
-  // addLocationAttribute(VariableDIE, GV, GlobalExprs);
-  return VariableDIE;
-}
-
 /// getOrCreateSubprogramDIE - Create new DIE using SP.
 IGC::DIE *CompileUnit::getOrCreateSubprogramDIE(DISubprogram *SP) {
   // Construct the context before querying for the existence of the DIE in case

IGC/DebugInfo/DwarfCompileUnit.hpp

@@ -24,7 +24,6 @@ See LICENSE.TXT for details.
 #include "llvm/ADT/DenseMap.h"
 #include <llvmWrapper/ADT/Optional.h>
 #include "llvm/ADT/SmallVector.h"
-#include <llvm/ADT/ArrayRef.h>
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Config/llvm-config.h"
@@ -162,12 +161,6 @@ class CompileUnit {
 
   DIEBlock *getDIEBlock() { return new (DIEValueAllocator) DIEBlock(); }
 
-  /// A pair of GlobalVariable and DIExpression.
-  struct GlobalExpr {
-    const llvm::GlobalVariable *Var;
-    const llvm::DIExpression *Expr;
-  };
-
   /// insertDIE - Insert DIE into the map. We delegate the request to DwarfDebug
   /// when the llvm::MDNode can be part of the type system, since DIEs for
   /// the type system can be shared across CUs and the mappings are
@@ -247,7 +240,6 @@ class CompileUnit {
   void addSourceLine(DIE *Die, llvm::DIVariable *V);
   void addSourceLine(DIE *Die, llvm::DISubprogram *SP);
   void addSourceLine(DIE *Die, llvm::DIType *Ty);
-  void addSourceLine(DIE *Die, llvm::DIGlobalVariable *GV);
 
   /// addConstantValue - Add constant value entry in variable DIE.
   void addConstantValue(DIE *Die, const llvm::ConstantInt *CI, bool Unsigned);
@@ -333,9 +325,6 @@ class CompileUnit {
   /// getOrCreateNameSpace - Create a DIE for DINameSpace.
   DIE *getOrCreateNameSpace(llvm::DINamespace *NS);
 
-  /// Get or create global variable DIE.
-  DIE *getOrCreateGlobalVariableDIE(llvm::DIGlobalVariable *GV, llvm::ArrayRef<GlobalExpr> GlobalExprs);
-
   /// getOrCreateSubprogramDIE - Create new DIE using SP.
   DIE *getOrCreateSubprogramDIE(llvm::DISubprogram *SP);
 

IGC/DebugInfo/DwarfDebug.cpp

@@ -1068,28 +1068,6 @@ IGCLLVM::optional<llvm::MD5::MD5Result> DwarfDebug::getMD5AsBytes(const llvm::DI
   return CKMem;
 }
 
-/// Sort and unique GVEs by comparing their fragment offset.
-static SmallVectorImpl<CompileUnit::GlobalExpr> &sortGlobalExprs(SmallVectorImpl<CompileUnit::GlobalExpr> &GVEs) {
-  llvm::sort(GVEs, [](CompileUnit::GlobalExpr A, CompileUnit::GlobalExpr B) {
-    // Sort order: first null exprs, then exprs without fragment
-    // info, then sort by fragment offset in bits.
-    // FIXME: Come up with a more comprehensive comparator so
-    // the sorting isn't non-deterministic, and so the following
-    // std::unique call works correctly.
-    if (!A.Expr || !B.Expr)
-      return !!B.Expr;
-    auto FragmentA = A.Expr->getFragmentInfo();
-    auto FragmentB = B.Expr->getFragmentInfo();
-    if (!FragmentA || !FragmentB)
-      return !!FragmentB;
-    return FragmentA->OffsetInBits < FragmentB->OffsetInBits;
-  });
-  GVEs.erase(std::unique(GVEs.begin(), GVEs.end(),
-                         [](CompileUnit::GlobalExpr A, CompileUnit::GlobalExpr B) { return A.Expr == B.Expr; }),
-             GVEs.end());
-  return GVEs;
-}
-
 // Emit all Dwarf sections that should come prior to the content. Create
 // global DIEs and emit initial debug info sections.
 void DwarfDebug::beginModule() {
@@ -1099,14 +1077,6 @@ void DwarfDebug::beginModule() {
   if (M->debug_compile_units().begin() == M->debug_compile_units().end())
     return;
 
-  DenseMap<DIGlobalVariable *, SmallVector<CompileUnit::GlobalExpr, 1>> GVMap;
-  for (const GlobalVariable &Global : M->globals()) {
-    SmallVector<DIGlobalVariableExpression *, 1> GVs;
-    Global.getDebugInfo(GVs);
-    for (auto *GVE : GVs)
-      GVMap[GVE->getVariable()].push_back({&Global, GVE->getExpression()});
-  }
-
   // discover DISubprogramNodes for all the registered visaModules
   discoverDISPNodes();
   // Emit initial sections so we can reference labels later.
@@ -1115,35 +1085,6 @@ void DwarfDebug::beginModule() {
   DICompileUnit *CUNode = *M->debug_compile_units_begin();
   CompileUnit *CU = constructCompileUnit(CUNode);
 
-  // Global Variables.
-  for (auto *GVE : CUNode->getGlobalVariables()) {
-    // Don't bother adding DIGlobalVariableExpressions listed in the CU if we
-    // already know about the variable and it isn't adding a constant
-    // expression.
-    auto &GVMapEntry = GVMap[GVE->getVariable()];
-    auto *Expr = GVE->getExpression();
-    if (!GVMapEntry.size() || (Expr && Expr->isConstant()))
-      GVMapEntry.push_back({nullptr, Expr});
-  }
-
-  DenseSet<DIGlobalVariable *> Processed;
-  for (auto *GVE : CUNode->getGlobalVariables()) {
-    DIGlobalVariable *GV = GVE->getVariable();
-
-    // Skip variables in different addrspaces than global,
-    // SLM globals and constants will be handled later. This
-    // will avoid duplication.
-    if (GVMap.find(GV) == GVMap.end())
-      continue;
-
-    bool AllInGlobalAS = llvm::all_of(GVMap.find(GV)->second, [](const CompileUnit::GlobalExpr &GE) {
-      return GE.Var && GE.Var->getAddressSpace() == ADDRESS_SPACE_GLOBAL;
-    });
-
-    if (Processed.insert(GV).second && AllInGlobalAS)
-      CU->getOrCreateGlobalVariableDIE(GV, sortGlobalExprs(GVMap[GV]));
-  }
-
   for (auto *DISP : DISubprogramNodes)
     constructSubprogramDIE(CU, DISP);