DWARF parser: remove duplicated code and fix code style in DIE extractors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179023 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 81 insertions, 268 deletions

diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.cpp b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
index 02b15d6904..0fd5d488ae 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.cpp
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
@@ -94,279 +94,87 @@ void DWARFDebugInfoEntryMinimal::dumpAttribute(raw_ostream &OS,
   OS << ")\n";
 }
 
-bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFCompileUnit *cu,
-                                             const uint8_t *fixed_form_sizes,
-                                             uint32_t *offset_ptr) {
-  Offset = *offset_ptr;
-
-  DataExtractor debug_info_data = cu->getDebugInfoExtractor();
-  uint64_t abbrCode = debug_info_data.getULEB128(offset_ptr);
-
-  assert(fixed_form_sizes); // For best performance this should be specified!
-
-  if (abbrCode) {
-    uint32_t offset = *offset_ptr;
-
-    AbbrevDecl = cu->getAbbreviations()->getAbbreviationDeclaration(abbrCode);
-
-    // Skip all data in the .debug_info for the attributes
-    const uint32_t numAttributes = AbbrevDecl->getNumAttributes();
-    uint32_t i;
-    uint16_t form;
-    for (i=0; i<numAttributes; ++i) {
-
-      form = AbbrevDecl->getFormByIndex(i);
-
-      // FIXME: Currently we're checking if this is less than the last
-      // entry in the fixed_form_sizes table, but this should be changed
-      // to use dynamic dispatch.
-      const uint8_t fixed_skip_size = (form < DW_FORM_ref_sig8) ?
-                                       fixed_form_sizes[form] : 0;
-      if (fixed_skip_size)
-        offset += fixed_skip_size;
-      else {
-        bool form_is_indirect = false;
-        do {
-          form_is_indirect = false;
-          uint32_t form_size = 0;
-          switch (form) {
-          // Blocks if inlined data that have a length field and the data bytes
-          // inlined in the .debug_info.
-          case DW_FORM_exprloc:
-          case DW_FORM_block:
-            form_size = debug_info_data.getULEB128(&offset);
-            break;
-          case DW_FORM_block1:
-            form_size = debug_info_data.getU8(&offset);
-            break;
-          case DW_FORM_block2:
-            form_size = debug_info_data.getU16(&offset);
-            break;
-          case DW_FORM_block4:
-            form_size = debug_info_data.getU32(&offset);
-            break;
-
-          // Inlined NULL terminated C-strings
-          case DW_FORM_string:
-            debug_info_data.getCStr(&offset);
-            break;
-
-          // Compile unit address sized values
-          case DW_FORM_addr:
-          case DW_FORM_ref_addr:
-            form_size = cu->getAddressByteSize();
-            break;
-
-          // 0 sized form.
-          case DW_FORM_flag_present:
-            form_size = 0;
-            break;
-
-          // 1 byte values
-          case DW_FORM_data1:
-          case DW_FORM_flag:
-          case DW_FORM_ref1:
-            form_size = 1;
-            break;
-
-          // 2 byte values
-          case DW_FORM_data2:
-          case DW_FORM_ref2:
-            form_size = 2;
-            break;
-
-          // 4 byte values
-          case DW_FORM_strp:
-          case DW_FORM_data4:
-          case DW_FORM_ref4:
-            form_size = 4;
-            break;
-
-          // 8 byte values
-          case DW_FORM_data8:
-          case DW_FORM_ref8:
-          case DW_FORM_ref_sig8:
-            form_size = 8;
-            break;
-
-          // signed or unsigned LEB 128 values
-          case DW_FORM_sdata:
-          case DW_FORM_udata:
-          case DW_FORM_ref_udata:
-          case DW_FORM_GNU_str_index:
-          case DW_FORM_GNU_addr_index:
-            debug_info_data.getULEB128(&offset);
-            break;
-
-          case DW_FORM_indirect:
-            form_is_indirect = true;
-            form = debug_info_data.getULEB128(&offset);
-            break;
-
-            // FIXME: 64-bit for DWARF64
-          case DW_FORM_sec_offset:
-            debug_info_data.getU32(offset_ptr);
-            break;
-
-          default:
-            *offset_ptr = Offset;
-            return false;
-          }
-          offset += form_size;
-        } while (form_is_indirect);
-      }
-    }
-    *offset_ptr = offset;
-    return true;
-  } else {
+bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFCompileUnit *CU,
+                                             const uint8_t *FixedFormSizes,
+                                             uint32_t *OffsetPtr) {
+  Offset = *OffsetPtr;
+  DataExtractor DebugInfoData = CU->getDebugInfoExtractor();
+  uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
+  if (0 == AbbrCode) {
+    // NULL debug tag entry.
     AbbrevDecl = NULL;
-    return true; // NULL debug tag entry
+    return true;
+  }
+  AbbrevDecl = CU->getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
+  assert(AbbrevDecl);
+  assert(FixedFormSizes); // For best performance this should be specified!
+
+  // Skip all data in the .debug_info for the attributes
+  for (uint32_t i = 0, n = AbbrevDecl->getNumAttributes(); i < n; ++i) {
+    uint16_t Form = AbbrevDecl->getFormByIndex(i);
+
+    // FIXME: Currently we're checking if this is less than the last
+    // entry in the fixed_form_sizes table, but this should be changed
+    // to use dynamic dispatch.
+    uint8_t FixedFormSize =
+        (Form < DW_FORM_ref_sig8) ? FixedFormSizes[Form] : 0;
+    if (FixedFormSize)
+      *OffsetPtr += FixedFormSize;
+    else if (!DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr,
+                                        CU)) {
+      // Restore the original offset.
+      *OffsetPtr = Offset;
+      return false;
+    }
   }
+  return true;
 }
 
 bool
-DWARFDebugInfoEntryMinimal::extract(const DWARFCompileUnit *cu,
-                                    uint32_t *offset_ptr) {
-  DataExtractor debug_info_data = cu->getDebugInfoExtractor();
-  const uint32_t cu_end_offset = cu->getNextCompileUnitOffset();
-  const uint8_t cu_addr_size = cu->getAddressByteSize();
-  uint32_t offset = *offset_ptr;
-  if ((offset < cu_end_offset) && debug_info_data.isValidOffset(offset)) {
-    Offset = offset;
-
-    uint64_t abbrCode = debug_info_data.getULEB128(&offset);
-
-    if (abbrCode) {
-      AbbrevDecl = cu->getAbbreviations()->getAbbreviationDeclaration(abbrCode);
-
-      if (AbbrevDecl) {
-        uint16_t tag = AbbrevDecl->getTag();
-
-        bool isCompileUnitTag = tag == DW_TAG_compile_unit;
-        if(cu && isCompileUnitTag)
-          const_cast<DWARFCompileUnit*>(cu)->setBaseAddress(0);
-
-        // Skip all data in the .debug_info for the attributes
-        const uint32_t numAttributes = AbbrevDecl->getNumAttributes();
-        for (uint32_t i = 0; i != numAttributes; ++i) {
-          uint16_t attr = AbbrevDecl->getAttrByIndex(i);
-          uint16_t form = AbbrevDecl->getFormByIndex(i);
-
-          if (isCompileUnitTag &&
-              ((attr == DW_AT_entry_pc) || (attr == DW_AT_low_pc))) {
-            DWARFFormValue form_value(form);
-            if (form_value.extractValue(debug_info_data, &offset, cu)) {
-              if (attr == DW_AT_low_pc || attr == DW_AT_entry_pc)
-                const_cast<DWARFCompileUnit*>(cu)
-                  ->setBaseAddress(form_value.getUnsigned());
-            }
-          } else {
-            bool form_is_indirect = false;
-            do {
-              form_is_indirect = false;
-              register uint32_t form_size = 0;
-              switch (form) {
-              // Blocks if inlined data that have a length field and the data
-              // bytes // inlined in the .debug_info
-              case DW_FORM_exprloc:
-              case DW_FORM_block:
-                form_size = debug_info_data.getULEB128(&offset);
-                break;
-              case DW_FORM_block1:
-                form_size = debug_info_data.getU8(&offset);
-                break;
-              case DW_FORM_block2:
-                form_size = debug_info_data.getU16(&offset);
-                break;
-              case DW_FORM_block4:
-                form_size = debug_info_data.getU32(&offset);
-                break;
-
-              // Inlined NULL terminated C-strings
-              case DW_FORM_string:
-                debug_info_data.getCStr(&offset);
-                break;
-
-              // Compile unit address sized values
-              case DW_FORM_addr:
-              case DW_FORM_ref_addr:
-                form_size = cu_addr_size;
-                break;
-
-              // 0 byte value
-              case DW_FORM_flag_present:
-                form_size = 0;
-                break;
-
-              // 1 byte values
-              case DW_FORM_data1:
-              case DW_FORM_flag:
-              case DW_FORM_ref1:
-                form_size = 1;
-                break;
-
-              // 2 byte values
-              case DW_FORM_data2:
-              case DW_FORM_ref2:
-                form_size = 2;
-                break;
-
-                // 4 byte values
-              case DW_FORM_strp:
-                form_size = 4;
-                break;
-
-              case DW_FORM_data4:
-              case DW_FORM_ref4:
-                form_size = 4;
-                break;
-
-              // 8 byte values
-              case DW_FORM_data8:
-              case DW_FORM_ref8:
-              case DW_FORM_ref_sig8:
-                form_size = 8;
-                break;
-
-              // signed or unsigned LEB 128 values
-              case DW_FORM_sdata:
-              case DW_FORM_udata:
-              case DW_FORM_ref_udata:
-              case DW_FORM_GNU_str_index:
-              case DW_FORM_GNU_addr_index:
-                debug_info_data.getULEB128(&offset);
-                break;
-
-              case DW_FORM_indirect:
-                form = debug_info_data.getULEB128(&offset);
-                form_is_indirect = true;
-                break;
-
-                // FIXME: 64-bit for DWARF64.
-              case DW_FORM_sec_offset:
-                debug_info_data.getU32(offset_ptr);
-                break;
-
-              default:
-                *offset_ptr = offset;
-                return false;
-              }
-
-              offset += form_size;
-            } while (form_is_indirect);
-          }
-        }
-        *offset_ptr = offset;
-        return true;
+DWARFDebugInfoEntryMinimal::extract(const DWARFCompileUnit *CU,
+                                    uint32_t *OffsetPtr) {
+  DataExtractor DebugInfoData = CU->getDebugInfoExtractor();
+  const uint32_t CUEndOffset = CU->getNextCompileUnitOffset();
+  Offset = *OffsetPtr;
+  if ((Offset >= CUEndOffset) || !DebugInfoData.isValidOffset(Offset))
+    return false;
+  uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
+  if (0 == AbbrCode) {
+    // NULL debug tag entry.
+    AbbrevDecl = NULL;
+    return true;
+  }
+  AbbrevDecl = CU->getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
+  if (0 == AbbrevDecl) {
+    // Restore the original offset.
+    *OffsetPtr = Offset;
+    return false;
+  }
+  bool IsCompileUnitTag = (AbbrevDecl->getTag() == DW_TAG_compile_unit);
+  if (IsCompileUnitTag)
+    const_cast<DWARFCompileUnit*>(CU)->setBaseAddress(0);
+
+  // Skip all data in the .debug_info for the attributes
+  for (uint32_t i = 0, n = AbbrevDecl->getNumAttributes(); i < n; ++i) {
+    uint16_t Attr = AbbrevDecl->getAttrByIndex(i);
+    uint16_t Form = AbbrevDecl->getFormByIndex(i);
+
+    if (IsCompileUnitTag &&
+        ((Attr == DW_AT_entry_pc) || (Attr == DW_AT_low_pc))) {
+      DWARFFormValue FormValue(Form);
+      if (FormValue.extractValue(DebugInfoData, OffsetPtr, CU)) {
+        if (Attr == DW_AT_low_pc || Attr == DW_AT_entry_pc)
+          const_cast<DWARFCompileUnit*>(CU)
+            ->setBaseAddress(FormValue.getUnsigned());
       }
-    } else {
-      AbbrevDecl = NULL;
-      *offset_ptr = offset;
-      return true;    // NULL debug tag entry
+    } else if (!DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr,
+                                          CU)) {
+      // Restore the original offset.
+      *OffsetPtr = Offset;
+      return false;
     }
   }
-
-  return false;
+  return true;
 }
 
 bool DWARFDebugInfoEntryMinimal::isSubprogramDIE() const {
diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.h b/lib/DebugInfo/DWARFDebugInfoEntry.h
index 9c1b2be0a7..9003591cbe 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.h
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.h
@@ -45,12 +45,17 @@ public:
                      uint32_t *offset_ptr, uint16_t attr, uint16_t form,
                      unsigned indent = 0) const;
 
-  bool extractFast(const DWARFCompileUnit *cu, const uint8_t *fixed_form_sizes,
-                   uint32_t *offset_ptr);
+  /// Extracts a debug info entry, which is a child of a given compile unit,
+  /// starting at a given offset. If DIE can't be extracted, returns false and
+  /// doesn't change OffsetPtr.
+  bool extractFast(const DWARFCompileUnit *CU, const uint8_t *FixedFormSizes,
+                   uint32_t *OffsetPtr);
 
   /// Extract a debug info entry for a given compile unit from the
   /// .debug_info and .debug_abbrev data starting at the given offset.
-  bool extract(const DWARFCompileUnit *cu, uint32_t *offset_ptr);
+  /// If compile unit can't be parsed, returns false and doesn't change
+  /// OffsetPtr.
+  bool extract(const DWARFCompileUnit *CU, uint32_t *OffsetPtr);
 
   uint32_t getTag() const { return AbbrevDecl ? AbbrevDecl->getTag() : 0; }
   bool isNULL() const { return AbbrevDecl == 0; }