Cleanup how DWARFDie attributes are accessed and decoded.

Removed all DWARFDie::getAttributeValueAs*() calls.
Renamed:
  Optional<DWARFFormValue> DWARFDie::getAttributeValue(dwarf::Attribute);
To:
  Optional<DWARFFormValue> DWARFDie::find(dwarf::Attribute);
Added:
  Optional<DWARFFormValue> DWARFDie::findRecursively(dwarf::Attribute);
  
All decoding of Optional<DWARFFormValue> values are now done using the dwarf::to*() functions from DWARFFormValue.h:

Old code:
  
  auto DeclLine = DWARFDie.getAttributeValueAsSignedConstant(DW_AT_decl_line).getValueOr(0);
  
New code:

  auto DeclLine = toUnsigned(DWARFDie.find(DW_AT_decl_line), 0);
  
This composition helps us since we can now easily do:

  auto DeclLine = toUnsigned(DWARFDie.findRecursively(DW_AT_decl_line), 0);
  
This allows us to easily find attribute values in the current DIE only (the first new code above) or in any DW_AT_abstract_origin or DW_AT_specification Dies using the line above. Note that the code line length is shorter and more concise.

Differential Revision: https://reviews.llvm.org/D28581

llvm-svn: 291959

4 files changed, 46 insertions, 89 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
index 77f6f65ee13..adc15b0481f 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFContext.cpp
@@ -128,8 +128,7 @@ void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType, bool DumpEH,
       auto CUDIE = CU->getUnitDIE();
       if (!CUDIE)
         continue;
-      if (auto StmtOffset =
-              CUDIE.getAttributeValueAsSectionOffset(DW_AT_stmt_list)) {
+      if (auto StmtOffset = toSectionOffset(CUDIE.find(DW_AT_stmt_list))) {
         DataExtractor lineData(getLineSection().Data, isLittleEndian(),
                                savedAddressByteSize);
         DWARFDebugLine::LineTable LineTable;
@@ -387,7 +386,7 @@ DWARFContext::getLineTableForUnit(DWARFUnit *U) {
   if (!UnitDIE)
     return nullptr;
 
-  auto Offset = UnitDIE.getAttributeValueAsSectionOffset(DW_AT_stmt_list);
+  auto Offset = toSectionOffset(UnitDIE.find(DW_AT_stmt_list));
   if (!Offset)
     return nullptr; // No line table for this compile unit.
 
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
index c4d347cf33d..11fb726f433 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
@@ -134,7 +134,7 @@ bool DWARFDie::isSubroutineDIE() const {
 }
 
 Optional<DWARFFormValue>
-DWARFDie::getAttributeValue(dwarf::Attribute Attr) const {
+DWARFDie::find(dwarf::Attribute Attr) const {
   if (!isValid())
     return None;
   auto AbbrevDecl = getAbbreviationDeclarationPtr();
@@ -143,54 +143,24 @@ DWARFDie::getAttributeValue(dwarf::Attribute Attr) const {
   return None;
 }
 
-const char *DWARFDie::getAttributeValueAsString(dwarf::Attribute Attr,
-                                                const char *FailValue) const {
-  auto FormValue = getAttributeValue(Attr);
-  if (!FormValue)
-    return FailValue;
-  Optional<const char *> Result = FormValue->getAsCString();
-  return Result.hasValue() ? Result.getValue() : FailValue;
-}
-
-Optional<uint64_t>
-DWARFDie::getAttributeValueAsAddress(dwarf::Attribute Attr) const {
-  if (auto FormValue = getAttributeValue(Attr))
-    return FormValue->getAsAddress();
-  return None;
-}
-
-Optional<int64_t>
-DWARFDie::getAttributeValueAsSignedConstant(dwarf::Attribute Attr) const {
-  if (auto FormValue = getAttributeValue(Attr))
-    return FormValue->getAsSignedConstant();
-  return None;
-}
-
-Optional<uint64_t>
-DWARFDie::getAttributeValueAsUnsignedConstant(dwarf::Attribute Attr) const {
-  if (auto FormValue = getAttributeValue(Attr))
-    return FormValue->getAsUnsignedConstant();
-  return None;
-}
-
-Optional<uint64_t>
-DWARFDie::getAttributeValueAsReference(dwarf::Attribute Attr) const {
-  if (auto FormValue = getAttributeValue(Attr))
-    return FormValue->getAsReference();
-  return None;
-}
-
-Optional<uint64_t>
-DWARFDie::getAttributeValueAsSectionOffset(dwarf::Attribute Attr) const {
-  if (auto FormValue = getAttributeValue(Attr))
-    return FormValue->getAsSectionOffset();
+Optional<DWARFFormValue>
+DWARFDie::findRecursively(dwarf::Attribute Attr) const {
+  if (!isValid())
+    return None;
+  if (auto Value = find(Attr))
+    return Value;
+  if (auto Die = getAttributeValueAsReferencedDie(DW_AT_abstract_origin))
+    if (auto Value = Die.find(Attr))
+      return Value;
+  if (auto Die = getAttributeValueAsReferencedDie(DW_AT_specification))
+    if (auto Value = Die.find(Attr))
+      return Value;
   return None;
 }
 
-
 DWARFDie
 DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
-  auto SpecRef = getAttributeValueAsReference(Attr);
+  auto SpecRef = toReference(find(Attr));
   if (SpecRef) {
     auto SpecUnit = U->getUnitSection().getUnitForOffset(*SpecRef);
     if (SpecUnit)
@@ -201,14 +171,14 @@ DWARFDie::getAttributeValueAsReferencedDie(dwarf::Attribute Attr) const {
 
 Optional<uint64_t>
 DWARFDie::getRangesBaseAttribute() const {
-  auto Result = getAttributeValueAsSectionOffset(DW_AT_rnglists_base);
+  auto Result = toSectionOffset(find(DW_AT_rnglists_base));
   if (Result)
     return Result;
-  return getAttributeValueAsSectionOffset(DW_AT_GNU_ranges_base);
+  return toSectionOffset(find(DW_AT_GNU_ranges_base));
 }
 
 Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
-  if (auto FormValue = getAttributeValue(DW_AT_high_pc)) {
+  if (auto FormValue = find(DW_AT_high_pc)) {
     if (auto Address = FormValue->getAsAddress()) {
       // High PC is an address.
       return Address;
@@ -222,7 +192,7 @@ Optional<uint64_t> DWARFDie::getHighPC(uint64_t LowPC) const {
 }
 
 bool DWARFDie::getLowAndHighPC(uint64_t &LowPC, uint64_t &HighPC) const {
-  auto LowPcAddr = getAttributeValueAsAddress(DW_AT_low_pc);
+  auto LowPcAddr = toAddress(find(DW_AT_low_pc));
   if (!LowPcAddr)
     return false;
   if (auto HighPcAddr = getHighPC(*LowPcAddr)) {
@@ -243,7 +213,7 @@ DWARFDie::getAddressRanges() const {
     return DWARFAddressRangesVector(1, std::make_pair(LowPC, HighPC));
   }
   // Multiple ranges from .debug_ranges section.
-  auto RangesOffset = getAttributeValueAsSectionOffset(DW_AT_ranges);
+  auto RangesOffset = toSectionOffset(find(DW_AT_ranges));
   if (RangesOffset) {
     DWARFDebugRangeList RangeList;
     if (U->extractRangeList(*RangesOffset, RangeList))
@@ -284,33 +254,25 @@ const char *
 DWARFDie::getName(DINameKind Kind) const {
   if (!isValid() || Kind == DINameKind::None)
     return nullptr;
-  const char *name = nullptr;
   // Try to get mangled name only if it was asked for.
   if (Kind == DINameKind::LinkageName) {
-    if ((name = getAttributeValueAsString(DW_AT_MIPS_linkage_name, nullptr)))
-      return name;
-    if ((name = getAttributeValueAsString(DW_AT_linkage_name, nullptr)))
-      return name;
+    if (auto Name = dwarf::toString(findRecursively(DW_AT_MIPS_linkage_name),
+                                    nullptr))
+      return Name;
+    if (auto Name = dwarf::toString(findRecursively(DW_AT_linkage_name),
+                                    nullptr))
+      return Name;
   }
-  if ((name = getAttributeValueAsString(DW_AT_name, nullptr)))
-    return name;
-  // Try to get name from specification DIE.
-  DWARFDie SpecDie = getAttributeValueAsReferencedDie(DW_AT_specification);
-  if (SpecDie && (name = SpecDie.getName(Kind)))
-    return name;
-  // Try to get name from abstract origin DIE.
-  DWARFDie AbsDie = getAttributeValueAsReferencedDie(DW_AT_abstract_origin);
-  if (AbsDie && (name = AbsDie.getName(Kind)))
-    return name;
+  if (auto Name = dwarf::toString(findRecursively(DW_AT_name), nullptr))
+    return Name;
   return nullptr;
 }
 
 void DWARFDie::getCallerFrame(uint32_t &CallFile, uint32_t &CallLine,
                               uint32_t &CallColumn) const {
-  CallFile = getAttributeValueAsUnsignedConstant(DW_AT_call_file).getValueOr(0);
-  CallLine = getAttributeValueAsUnsignedConstant(DW_AT_call_line).getValueOr(0);
-  CallColumn =
-      getAttributeValueAsUnsignedConstant(DW_AT_call_column).getValueOr(0);
+  CallFile = toUnsigned(find(DW_AT_call_file), 0);
+  CallLine = toUnsigned(find(DW_AT_call_line), 0);
+  CallColumn = toUnsigned(find(DW_AT_call_column), 0);
 }
 
 void DWARFDie::dump(raw_ostream &OS, unsigned RecurseDepth,
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp
index 88fb20381f9..b468ba28c94 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFTypeUnit.cpp
@@ -26,7 +26,7 @@ bool DWARFTypeUnit::extractImpl(DataExtractor debug_info,
 
 void DWARFTypeUnit::dump(raw_ostream &OS, bool SummarizeTypes) {
   DWARFDie TD = getDIEForOffset(TypeOffset + getOffset());
-  const char *Name = TD.getAttributeValueAsString(llvm::dwarf::DW_AT_name, "");
+  const char *Name = TD.getName(DINameKind::ShortName);
 
   if (SummarizeTypes) {
     OS << "name = '" << Name << "'"
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
index ee2c569b0bc..e0dcd9b20b2 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -13,6 +13,7 @@
 #include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
+#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/Casting.h"
@@ -151,11 +152,11 @@ void DWARFUnit::clear() {
 }
 
 const char *DWARFUnit::getCompilationDir() {
-  return getUnitDIE().getAttributeValueAsString(DW_AT_comp_dir, nullptr);
+  return toString(getUnitDIE().find(DW_AT_comp_dir), nullptr);
 }
 
 Optional<uint64_t> DWARFUnit::getDWOId() {
-  return getUnitDIE().getAttributeValueAsUnsignedConstant(DW_AT_GNU_dwo_id);
+  return toUnsigned(getUnitDIE().find(DW_AT_GNU_dwo_id));
 }
 
 void DWARFUnit::extractDIEsToVector(
@@ -225,17 +226,13 @@ size_t DWARFUnit::extractDIEsIfNeeded(bool CUDieOnly) {
   // If CU DIE was just parsed, copy several attribute values from it.
   if (!HasCUDie) {
     DWARFDie UnitDie = getUnitDIE();
-    auto BaseAddr = UnitDie.getAttributeValueAsAddress(DW_AT_low_pc);
+    auto BaseAddr = toAddress(UnitDie.find(DW_AT_low_pc));
     if (!BaseAddr)
-      BaseAddr = UnitDie.getAttributeValueAsAddress(DW_AT_entry_pc);
+      BaseAddr = toAddress(UnitDie.find(DW_AT_entry_pc));
     if (BaseAddr)
       setBaseAddress(*BaseAddr);
-    AddrOffsetSectionBase =
-        UnitDie.getAttributeValueAsSectionOffset(DW_AT_GNU_addr_base)
-            .getValueOr(0);
-    RangeSectionBase =
-        UnitDie.getAttributeValueAsSectionOffset(DW_AT_rnglists_base)
-            .getValueOr(0);
+    AddrOffsetSectionBase = toSectionOffset(UnitDie.find(DW_AT_GNU_addr_base), 0);
+    RangeSectionBase = toSectionOffset(UnitDie.find(DW_AT_rnglists_base), 0);
     // Don't fall back to DW_AT_GNU_ranges_base: it should be ignored for
     // skeleton CU DIE, so that DWARF users not aware of it are not broken.
   }
@@ -266,17 +263,16 @@ bool DWARFUnit::parseDWO() {
   DWARFDie UnitDie = getUnitDIE();
   if (!UnitDie)
     return false;
-  const char *DWOFileName =
-      UnitDie.getAttributeValueAsString(DW_AT_GNU_dwo_name, nullptr);
+  auto DWOFileName = toString(UnitDie.find(DW_AT_GNU_dwo_name));
   if (!DWOFileName)
     return false;
-  const char *CompilationDir =
-      UnitDie.getAttributeValueAsString(DW_AT_comp_dir, nullptr);
+  auto CompilationDir = toString(UnitDie.find(DW_AT_comp_dir));
   SmallString<16> AbsolutePath;
-  if (sys::path::is_relative(DWOFileName) && CompilationDir != nullptr) {
-    sys::path::append(AbsolutePath, CompilationDir);
+  if (sys::path::is_relative(*DWOFileName) && CompilationDir &&
+      *CompilationDir) {
+    sys::path::append(AbsolutePath, *CompilationDir);
   }
-  sys::path::append(AbsolutePath, DWOFileName);
+  sys::path::append(AbsolutePath, *DWOFileName);
   DWO = llvm::make_unique<DWOHolder>(AbsolutePath);
   DWARFUnit *DWOCU = DWO->getUnit();
   // Verify that compile unit in .dwo file is valid.