1 files changed, 277 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
new file mode 100644
index 00000000000..b7a56e32513
--- /dev/null
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -0,0 +1,277 @@
+#include "DwarfCompileUnit.h"
+
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/GlobalValue.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Target/TargetLoweringObjectFile.h"
+
+namespace llvm {
+
+DwarfCompileUnit::DwarfCompileUnit(unsigned UID, DICompileUnit Node,
+                                   AsmPrinter *A, DwarfDebug *DW,
+                                   DwarfFile *DWU)
+    : DwarfUnit(UID, dwarf::DW_TAG_compile_unit, Node, A, DW, DWU) {
+  insertDIE(Node, &getUnitDie());
+}
+
+/// addLabelAddress - Add a dwarf label attribute data and value using
+/// DW_FORM_addr or DW_FORM_GNU_addr_index.
+///
+void DwarfCompileUnit::addLabelAddress(DIE &Die, dwarf::Attribute Attribute,
+                                       const MCSymbol *Label) {
+
+  // Don't use the address pool in non-fission or in the skeleton unit itself.
+  // FIXME: Once GDB supports this, it's probably worthwhile using the address
+  // pool from the skeleton - maybe even in non-fission (possibly fewer
+  // relocations by sharing them in the pool, but we have other ideas about how
+  // to reduce the number of relocations as well/instead).
+  if (!DD->useSplitDwarf() || !Skeleton)
+    return addLocalLabelAddress(Die, Attribute, Label);
+
+  if (Label)
+    DD->addArangeLabel(SymbolCU(this, Label));
+
+  unsigned idx = DD->getAddressPool().getIndex(Label);
+  DIEValue *Value = new (DIEValueAllocator) DIEInteger(idx);
+  Die.addValue(Attribute, dwarf::DW_FORM_GNU_addr_index, Value);
+}
+
+void DwarfCompileUnit::addLocalLabelAddress(DIE &Die,
+                                            dwarf::Attribute Attribute,
+                                            const MCSymbol *Label) {
+  if (Label)
+    DD->addArangeLabel(SymbolCU(this, Label));
+
+  Die.addValue(Attribute, dwarf::DW_FORM_addr,
+               Label ? (DIEValue *)new (DIEValueAllocator) DIELabel(Label)
+                     : new (DIEValueAllocator) DIEInteger(0));
+}
+
+unsigned DwarfCompileUnit::getOrCreateSourceID(StringRef FileName, StringRef DirName) {
+  // If we print assembly, we can't separate .file entries according to
+  // compile units. Thus all files will belong to the default compile unit.
+
+  // FIXME: add a better feature test than hasRawTextSupport. Even better,
+  // extend .file to support this.
+  return Asm->OutStreamer.EmitDwarfFileDirective(
+      0, DirName, FileName,
+      Asm->OutStreamer.hasRawTextSupport() ? 0 : getUniqueID());
+}
+
+// Return const expression if value is a GEP to access merged global
+// constant. e.g.
+// i8* getelementptr ({ i8, i8, i8, i8 }* @_MergedGlobals, i32 0, i32 0)
+static const ConstantExpr *getMergedGlobalExpr(const Value *V) {
+  const ConstantExpr *CE = dyn_cast_or_null<ConstantExpr>(V);
+  if (!CE || CE->getNumOperands() != 3 ||
+      CE->getOpcode() != Instruction::GetElementPtr)
+    return nullptr;
+
+  // First operand points to a global struct.
+  Value *Ptr = CE->getOperand(0);
+  if (!isa<GlobalValue>(Ptr) ||
+      !isa<StructType>(cast<PointerType>(Ptr->getType())->getElementType()))
+    return nullptr;
+
+  // Second operand is zero.
+  const ConstantInt *CI = dyn_cast_or_null<ConstantInt>(CE->getOperand(1));
+  if (!CI || !CI->isZero())
+    return nullptr;
+
+  // Third operand is offset.
+  if (!isa<ConstantInt>(CE->getOperand(2)))
+    return nullptr;
+
+  return CE;
+}
+
+/// getOrCreateGlobalVariableDIE - get or create global variable DIE.
+DIE *DwarfCompileUnit::getOrCreateGlobalVariableDIE(DIGlobalVariable GV) {
+  // Check for pre-existence.
+  if (DIE *Die = getDIE(GV))
+    return Die;
+
+  assert(GV.isGlobalVariable());
+
+  DIScope GVContext = GV.getContext();
+  DIType GTy = DD->resolve(GV.getType());
+
+  // If this is a static data member definition, some attributes belong
+  // to the declaration DIE.
+  DIE *VariableDIE = nullptr;
+  bool IsStaticMember = false;
+  DIDerivedType SDMDecl = GV.getStaticDataMemberDeclaration();
+  if (SDMDecl.Verify()) {
+    assert(SDMDecl.isStaticMember() && "Expected static member decl");
+    // We need the declaration DIE that is in the static member's class.
+    VariableDIE = getOrCreateStaticMemberDIE(SDMDecl);
+    IsStaticMember = true;
+  }
+
+  // If this is not a static data member definition, create the variable
+  // DIE and add the initial set of attributes to it.
+  if (!VariableDIE) {
+    // Construct the context before querying for the existence of the DIE in
+    // case such construction creates the DIE.
+    DIE *ContextDIE = getOrCreateContextDIE(GVContext);
+
+    // Add to map.
+    VariableDIE = &createAndAddDIE(GV.getTag(), *ContextDIE, GV);
+
+    // Add name and type.
+    addString(*VariableDIE, dwarf::DW_AT_name, GV.getDisplayName());
+    addType(*VariableDIE, GTy);
+
+    // Add scoping info.
+    if (!GV.isLocalToUnit())
+      addFlag(*VariableDIE, dwarf::DW_AT_external);
+
+    // Add line number info.
+    addSourceLine(*VariableDIE, GV);
+  }
+
+  // Add location.
+  bool addToAccelTable = false;
+  DIE *VariableSpecDIE = nullptr;
+  bool isGlobalVariable = GV.getGlobal() != nullptr;
+  if (isGlobalVariable) {
+    addToAccelTable = true;
+    DIELoc *Loc = new (DIEValueAllocator) DIELoc();
+    const MCSymbol *Sym = Asm->getSymbol(GV.getGlobal());
+    if (GV.getGlobal()->isThreadLocal()) {
+      // FIXME: Make this work with -gsplit-dwarf.
+      unsigned PointerSize = Asm->getDataLayout().getPointerSize();
+      assert((PointerSize == 4 || PointerSize == 8) &&
+             "Add support for other sizes if necessary");
+      // Based on GCC's support for TLS:
+      if (!DD->useSplitDwarf()) {
+        // 1) Start with a constNu of the appropriate pointer size
+        addUInt(*Loc, dwarf::DW_FORM_data1,
+                PointerSize == 4 ? dwarf::DW_OP_const4u : dwarf::DW_OP_const8u);
+        // 2) containing the (relocated) offset of the TLS variable
+        //    within the module's TLS block.
+        addExpr(*Loc, dwarf::DW_FORM_udata,
+                Asm->getObjFileLowering().getDebugThreadLocalSymbol(Sym));
+      } else {
+        addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_const_index);
+        addUInt(*Loc, dwarf::DW_FORM_udata,
+                DD->getAddressPool().getIndex(Sym, /* TLS */ true));
+      }
+      // 3) followed by a custom OP to make the debugger do a TLS lookup.
+      addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_push_tls_address);
+    } else {
+      DD->addArangeLabel(SymbolCU(this, Sym));
+      addOpAddress(*Loc, Sym);
+    }
+    // A static member's declaration is already flagged as such.
+    if (!SDMDecl.Verify() && !GV.isDefinition())
+      addFlag(*VariableDIE, dwarf::DW_AT_declaration);
+    // Do not create specification DIE if context is either compile unit
+    // or a subprogram.
+    if (GVContext && GV.isDefinition() && !GVContext.isCompileUnit() &&
+        !GVContext.isFile() && !DD->isSubprogramContext(GVContext)) {
+      // Create specification DIE.
+      VariableSpecDIE = &createAndAddDIE(dwarf::DW_TAG_variable, UnitDie);
+      addDIEEntry(*VariableSpecDIE, dwarf::DW_AT_specification, *VariableDIE);
+      addBlock(*VariableSpecDIE, dwarf::DW_AT_location, Loc);
+      // A static member's declaration is already flagged as such.
+      if (!SDMDecl.Verify())
+        addFlag(*VariableDIE, dwarf::DW_AT_declaration);
+    } else {
+      addBlock(*VariableDIE, dwarf::DW_AT_location, Loc);
+    }
+    // Add the linkage name.
+    StringRef LinkageName = GV.getLinkageName();
+    if (!LinkageName.empty())
+      // From DWARF4: DIEs to which DW_AT_linkage_name may apply include:
+      // TAG_common_block, TAG_constant, TAG_entry_point, TAG_subprogram and
+      // TAG_variable.
+      addString(IsStaticMember && VariableSpecDIE ? *VariableSpecDIE
+                                                  : *VariableDIE,
+                DD->getDwarfVersion() >= 4 ? dwarf::DW_AT_linkage_name
+                                           : dwarf::DW_AT_MIPS_linkage_name,
+                GlobalValue::getRealLinkageName(LinkageName));
+  } else if (const ConstantInt *CI =
+                 dyn_cast_or_null<ConstantInt>(GV.getConstant())) {
+    // AT_const_value was added when the static member was created. To avoid
+    // emitting AT_const_value multiple times, we only add AT_const_value when
+    // it is not a static member.
+    if (!IsStaticMember)
+      addConstantValue(*VariableDIE, CI, GTy);
+  } else if (const ConstantExpr *CE = getMergedGlobalExpr(GV.getConstant())) {
+    addToAccelTable = true;
+    // GV is a merged global.
+    DIELoc *Loc = new (DIEValueAllocator) DIELoc();
+    Value *Ptr = CE->getOperand(0);
+    MCSymbol *Sym = Asm->getSymbol(cast<GlobalValue>(Ptr));
+    DD->addArangeLabel(SymbolCU(this, Sym));
+    addOpAddress(*Loc, Sym);
+    addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_constu);
+    SmallVector<Value *, 3> Idx(CE->op_begin() + 1, CE->op_end());
+    addUInt(*Loc, dwarf::DW_FORM_udata,
+            Asm->getDataLayout().getIndexedOffset(Ptr->getType(), Idx));
+    addUInt(*Loc, dwarf::DW_FORM_data1, dwarf::DW_OP_plus);
+    addBlock(*VariableDIE, dwarf::DW_AT_location, Loc);
+  }
+
+  DIE *ResultDIE = VariableSpecDIE ? VariableSpecDIE : VariableDIE;
+
+  if (addToAccelTable) {
+    DD->addAccelName(GV.getName(), *ResultDIE);
+
+    // If the linkage name is different than the name, go ahead and output
+    // that as well into the name table.
+    if (GV.getLinkageName() != "" && GV.getName() != GV.getLinkageName())
+      DD->addAccelName(GV.getLinkageName(), *ResultDIE);
+  }
+
+  addGlobalName(GV.getName(), *ResultDIE, GV.getContext());
+  return ResultDIE;
+}
+
+void DwarfCompileUnit::addRange(RangeSpan Range) {
+  bool SameAsPrevCU = this == DD->getPrevCU();
+  DD->setPrevCU(this);
+  // If we have no current ranges just add the range and return, otherwise,
+  // check the current section and CU against the previous section and CU we
+  // emitted into and the subprogram was contained within. If these are the
+  // same then extend our current range, otherwise add this as a new range.
+  if (CURanges.empty() || !SameAsPrevCU ||
+      (&CURanges.back().getEnd()->getSection() !=
+       &Range.getEnd()->getSection())) {
+    CURanges.push_back(Range);
+    return;
+  }
+
+  CURanges.back().setEnd(Range.getEnd());
+}
+
+void DwarfCompileUnit::initStmtList(MCSymbol *DwarfLineSectionSym) {
+  // Define start line table label for each Compile Unit.
+  MCSymbol *LineTableStartSym =
+      Asm->OutStreamer.getDwarfLineTableSymbol(getUniqueID());
+
+  stmtListIndex = UnitDie.getValues().size();
+
+  // DW_AT_stmt_list is a offset of line number information for this
+  // compile unit in debug_line section. For split dwarf this is
+  // left in the skeleton CU and so not included.
+  // The line table entries are not always emitted in assembly, so it
+  // is not okay to use line_table_start here.
+  if (Asm->MAI->doesDwarfUseRelocationsAcrossSections())
+    addSectionLabel(UnitDie, dwarf::DW_AT_stmt_list, LineTableStartSym);
+  else
+    addSectionDelta(UnitDie, dwarf::DW_AT_stmt_list, LineTableStartSym,
+                    DwarfLineSectionSym);
+}
+
+void DwarfCompileUnit::applyStmtList(DIE &D) {
+  D.addValue(dwarf::DW_AT_stmt_list,
+             UnitDie.getAbbrev().getData()[stmtListIndex].getForm(),
+             UnitDie.getValues()[stmtListIndex]);
+}
+
+} // end llvm namespace