Replace HashStringUsingDJB with llvm::djbHash

Summary:
The llvm function is equivalent to this one. Where possible I tried to
replace const char* with llvm::StringRef to avoid extra strlen
computations. In most places, I was able to track the c string back to
the ConstString it was created from.

I also create a test that verifies we are able to lookup names with
unicode characters, as a bug in the llvm compiler (it accidentally used
a different hash function) meant this was not working until recently.

This also removes the unused ExportTable class.

Reviewers: aprantl, davide

Subscribers: JDevlieghere, lldb-commits

Differential Revision: https://reviews.llvm.org/D43596

llvm-svn: 325927

4 files changed, 45 insertions, 47 deletions

diff --git a/lldb/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.cpp b/lldb/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.cpp
index cb1e5c18561..629ae8b0a6a 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.cpp
@@ -379,7 +379,8 @@ bool DWARFMappedHash::MemoryTable::ReadHashData(uint32_t hash_data_offset,
 
 DWARFMappedHash::MemoryTable::Result
 DWARFMappedHash::MemoryTable::GetHashDataForName(
-    const char *name, lldb::offset_t *hash_data_offset_ptr, Pair &pair) const {
+    llvm::StringRef name, lldb::offset_t *hash_data_offset_ptr,
+    Pair &pair) const {
   pair.key = m_data.GetU32(hash_data_offset_ptr);
   pair.value.clear();
 
@@ -406,7 +407,7 @@ DWARFMappedHash::MemoryTable::GetHashDataForName(
     // data to parse at least "count" HashData entries.
 
     // First make sure the entire C string matches...
-    const bool match = strcmp(name, strp_cstr) == 0;
+    const bool match = name == strp_cstr;
 
     if (!match && m_header.header_data.HashDataHasFixedByteSize()) {
       // If the string doesn't match and we have fixed size data,
@@ -573,9 +574,9 @@ size_t DWARFMappedHash::MemoryTable::AppendAllDIEsInRange(
   return die_info_array.size();
 }
 
-size_t DWARFMappedHash::MemoryTable::FindByName(const char *name,
+size_t DWARFMappedHash::MemoryTable::FindByName(llvm::StringRef name,
                                                 DIEArray &die_offsets) {
-  if (!name || !name[0])
+  if (name.empty())
     return 0;
 
   DIEInfoArray die_info_array;
@@ -584,7 +585,7 @@ size_t DWARFMappedHash::MemoryTable::FindByName(const char *name,
   return die_info_array.size();
 }
 
-size_t DWARFMappedHash::MemoryTable::FindByNameAndTag(const char *name,
+size_t DWARFMappedHash::MemoryTable::FindByNameAndTag(llvm::StringRef name,
                                                       const dw_tag_t tag,
                                                       DIEArray &die_offsets) {
   DIEInfoArray die_info_array;
@@ -594,8 +595,8 @@ size_t DWARFMappedHash::MemoryTable::FindByNameAndTag(const char *name,
 }
 
 size_t DWARFMappedHash::MemoryTable::FindByNameAndTagAndQualifiedNameHash(
-    const char *name, const dw_tag_t tag, const uint32_t qualified_name_hash,
-    DIEArray &die_offsets) {
+    llvm::StringRef name, const dw_tag_t tag,
+    const uint32_t qualified_name_hash, DIEArray &die_offsets) {
   DIEInfoArray die_info_array;
   if (FindByName(name, die_info_array))
     DWARFMappedHash::ExtractDIEArray(die_info_array, tag, qualified_name_hash,
@@ -604,7 +605,7 @@ size_t DWARFMappedHash::MemoryTable::FindByNameAndTagAndQualifiedNameHash(
 }
 
 size_t DWARFMappedHash::MemoryTable::FindCompleteObjCClassByName(
-    const char *name, DIEArray &die_offsets, bool must_be_implementation) {
+    llvm::StringRef name, DIEArray &die_offsets, bool must_be_implementation) {
   DIEInfoArray die_info_array;
   if (FindByName(name, die_info_array)) {
     if (must_be_implementation &&
@@ -628,9 +629,9 @@ size_t DWARFMappedHash::MemoryTable::FindCompleteObjCClassByName(
   return die_offsets.size();
 }
 
-size_t DWARFMappedHash::MemoryTable::FindByName(const char *name,
+size_t DWARFMappedHash::MemoryTable::FindByName(llvm::StringRef name,
                                                 DIEInfoArray &die_info_array) {
-  if (!name || !name[0])
+  if (name.empty())
     return 0;
 
   Pair kv_pair;
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.h b/lldb/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.h
index b38473dee9c..dc2d4ff93e3 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/HashedNameToDIE.h
@@ -132,17 +132,17 @@ public:
                                 const uint32_t die_offset_end,
                                 DIEInfoArray &die_info_array) const;
 
-    size_t FindByName(const char *name, DIEArray &die_offsets);
+    size_t FindByName(llvm::StringRef name, DIEArray &die_offsets);
 
-    size_t FindByNameAndTag(const char *name, const dw_tag_t tag,
+    size_t FindByNameAndTag(llvm::StringRef name, const dw_tag_t tag,
                             DIEArray &die_offsets);
 
-    size_t
-    FindByNameAndTagAndQualifiedNameHash(const char *name, const dw_tag_t tag,
-                                         const uint32_t qualified_name_hash,
-                                         DIEArray &die_offsets);
+    size_t FindByNameAndTagAndQualifiedNameHash(
+        llvm::StringRef name, const dw_tag_t tag,
+        const uint32_t qualified_name_hash, DIEArray &die_offsets);
 
-    size_t FindCompleteObjCClassByName(const char *name, DIEArray &die_offsets,
+    size_t FindCompleteObjCClassByName(llvm::StringRef name,
+                                       DIEArray &die_offsets,
                                        bool must_be_implementation);
 
   protected:
@@ -150,9 +150,9 @@ public:
         const lldb_private::RegularExpression &regex,
         lldb::offset_t *hash_data_offset_ptr, Pair &pair) const;
 
-    size_t FindByName(const char *name, DIEInfoArray &die_info_array);
+    size_t FindByName(llvm::StringRef name, DIEInfoArray &die_info_array);
 
-    Result GetHashDataForName(const char *name,
+    Result GetHashDataForName(llvm::StringRef name,
                               lldb::offset_t *hash_data_offset_ptr,
                               Pair &pair) const override;
 
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
index 6ef26d82629..4a5dd818b0f 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -1510,7 +1510,8 @@ size_t SymbolFileDWARF::GetObjCMethodDIEOffsets(ConstString class_name,
   method_die_offsets.clear();
   if (m_using_apple_tables) {
     if (m_apple_objc_ap.get())
-      m_apple_objc_ap->FindByName(class_name.GetCString(), method_die_offsets);
+      m_apple_objc_ap->FindByName(class_name.GetStringRef(),
+                                  method_die_offsets);
   } else {
     if (!m_indexed)
       Index();
@@ -2183,7 +2184,7 @@ uint32_t SymbolFileDWARF::FindGlobalVariables(
                                                           basename))
         basename = name_cstr;
 
-      m_apple_names_ap->FindByName(basename.data(), die_offsets);
+      m_apple_names_ap->FindByName(basename, die_offsets);
     }
   } else {
     // Index the DWARF if we haven't already
@@ -2489,8 +2490,6 @@ SymbolFileDWARF::FindFunctions(const ConstString &name,
   // Remember how many sc_list are in the list before we search in case
   // we are appending the results to a variable list.
 
-  const char *name_cstr = name.GetCString();
-
   const uint32_t original_size = sc_list.GetSize();
 
   DWARFDebugInfo *info = DebugInfo();
@@ -2511,7 +2510,8 @@ SymbolFileDWARF::FindFunctions(const ConstString &name,
         // want to canonicalize this (strip double spaces, etc.  For now, we
         // just add all the
         // dies that we find by exact match.
-        num_matches = m_apple_names_ap->FindByName(name_cstr, die_offsets);
+        num_matches =
+            m_apple_names_ap->FindByName(name.GetStringRef(), die_offsets);
         for (uint32_t i = 0; i < num_matches; i++) {
           const DIERef &die_ref = die_offsets[i];
           DWARFDIE die = info->GetDIE(die_ref);
@@ -2527,7 +2527,7 @@ SymbolFileDWARF::FindFunctions(const ConstString &name,
             GetObjectFile()->GetModule()->ReportErrorIfModifyDetected(
                 "the DWARF debug information has been modified (.apple_names "
                 "accelerator table had bad die 0x%8.8x for '%s')",
-                die_ref.die_offset, name_cstr);
+                die_ref.die_offset, name.GetCString());
           }
         }
       }
@@ -2536,7 +2536,8 @@ SymbolFileDWARF::FindFunctions(const ConstString &name,
         if (parent_decl_ctx && parent_decl_ctx->IsValid())
           return 0; // no selectors in namespaces
 
-        num_matches = m_apple_names_ap->FindByName(name_cstr, die_offsets);
+        num_matches =
+            m_apple_names_ap->FindByName(name.GetStringRef(), die_offsets);
         // Now make sure these are actually ObjC methods.  In this case we can
         // simply look up the name,
         // and if it is an ObjC method name, we're good.
@@ -2556,7 +2557,7 @@ SymbolFileDWARF::FindFunctions(const ConstString &name,
             GetObjectFile()->GetModule()->ReportError(
                 "the DWARF debug information has been modified (.apple_names "
                 "accelerator table had bad die 0x%8.8x for '%s')",
-                die_ref.die_offset, name_cstr);
+                die_ref.die_offset, name.GetCString());
           }
         }
         die_offsets.clear();
@@ -2572,7 +2573,8 @@ SymbolFileDWARF::FindFunctions(const ConstString &name,
 
         // FIXME: Arrange the logic above so that we don't calculate the base
         // name twice:
-        num_matches = m_apple_names_ap->FindByName(name_cstr, die_offsets);
+        num_matches =
+            m_apple_names_ap->FindByName(name.GetStringRef(), die_offsets);
 
         for (uint32_t i = 0; i < num_matches; i++) {
           const DIERef &die_ref = die_offsets[i];
@@ -2626,7 +2628,7 @@ SymbolFileDWARF::FindFunctions(const ConstString &name,
             GetObjectFile()->GetModule()->ReportErrorIfModifyDetected(
                 "the DWARF debug information has been modified (.apple_names "
                 "accelerator table had bad die 0x%8.8x for '%s')",
-                die_ref.die_offset, name_cstr);
+                die_ref.die_offset, name.GetCString());
           }
         }
         die_offsets.clear();
@@ -2850,8 +2852,7 @@ uint32_t SymbolFileDWARF::FindTypes(
 
   if (m_using_apple_tables) {
     if (m_apple_types_ap.get()) {
-      const char *name_cstr = name.GetCString();
-      m_apple_types_ap->FindByName(name_cstr, die_offsets);
+      m_apple_types_ap->FindByName(name.GetStringRef(), die_offsets);
     }
   } else {
     if (!m_indexed)
@@ -2944,8 +2945,7 @@ size_t SymbolFileDWARF::FindTypes(const std::vector<CompilerContext> &context,
 
   if (m_using_apple_tables) {
     if (m_apple_types_ap.get()) {
-      const char *name_cstr = name.GetCString();
-      m_apple_types_ap->FindByName(name_cstr, die_offsets);
+      m_apple_types_ap->FindByName(name.GetStringRef(), die_offsets);
     }
   } else {
     if (!m_indexed)
@@ -3013,8 +3013,7 @@ SymbolFileDWARF::FindNamespace(const SymbolContext &sc, const ConstString &name,
     // get indexed and make their global DIE index list
     if (m_using_apple_tables) {
       if (m_apple_namespaces_ap.get()) {
-        const char *name_cstr = name.GetCString();
-        m_apple_namespaces_ap->FindByName(name_cstr, die_offsets);
+        m_apple_namespaces_ap->FindByName(name.GetStringRef(), die_offsets);
       }
     } else {
       if (!m_indexed)
@@ -3207,9 +3206,8 @@ TypeSP SymbolFileDWARF::FindCompleteObjCDefinitionTypeForDIE(
 
   if (m_using_apple_tables) {
     if (m_apple_types_ap.get()) {
-      const char *name_cstr = type_name.GetCString();
-      m_apple_types_ap->FindCompleteObjCClassByName(name_cstr, die_offsets,
-                                                    must_be_implementation);
+      m_apple_types_ap->FindCompleteObjCClassByName(
+          type_name.GetStringRef(), die_offsets, must_be_implementation);
     }
   } else {
     if (!m_indexed)
@@ -3398,21 +3396,21 @@ TypeSP SymbolFileDWARF::FindDefinitionTypeForDWARFDeclContext(
                   DWARFMappedHash::eAtomTypeQualNameHash);
           if (has_tag && has_qualified_name_hash) {
             const char *qualified_name = dwarf_decl_ctx.GetQualifiedName();
-            const uint32_t qualified_name_hash =
-                MappedHash::HashStringUsingDJB(qualified_name);
+            const uint32_t qualified_name_hash = llvm::djbHash(qualified_name);
             if (log)
               GetObjectFile()->GetModule()->LogMessage(
                   log, "FindByNameAndTagAndQualifiedNameHash()");
             m_apple_types_ap->FindByNameAndTagAndQualifiedNameHash(
-                type_name.GetCString(), tag, qualified_name_hash, die_offsets);
+                type_name.GetStringRef(), tag, qualified_name_hash,
+                die_offsets);
           } else if (has_tag) {
             if (log)
               GetObjectFile()->GetModule()->LogMessage(log,
                                                        "FindByNameAndTag()");
-            m_apple_types_ap->FindByNameAndTag(type_name.GetCString(), tag,
+            m_apple_types_ap->FindByNameAndTag(type_name.GetStringRef(), tag,
                                                die_offsets);
           } else {
-            m_apple_types_ap->FindByName(type_name.GetCString(), die_offsets);
+            m_apple_types_ap->FindByName(type_name.GetStringRef(), die_offsets);
           }
         }
       } else {
diff --git a/lldb/source/Target/ObjCLanguageRuntime.cpp b/lldb/source/Target/ObjCLanguageRuntime.cpp
index d3cc7c019dc..e50167dcb58 100644
--- a/lldb/source/Target/ObjCLanguageRuntime.cpp
+++ b/lldb/source/Target/ObjCLanguageRuntime.cpp
@@ -23,6 +23,7 @@
 #include "lldb/Utility/Timer.h"
 
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/DJB.h"
 
 using namespace lldb;
 using namespace lldb_private;
@@ -45,8 +46,7 @@ bool ObjCLanguageRuntime::AddClass(ObjCISA isa,
   if (isa != 0) {
     m_isa_to_descriptor[isa] = descriptor_sp;
     // class_name is assumed to be valid
-    m_hash_to_isa_map.insert(
-        std::make_pair(MappedHash::HashStringUsingDJB(class_name), isa));
+    m_hash_to_isa_map.insert(std::make_pair(llvm::djbHash(class_name), isa));
     return true;
   }
   return false;
@@ -180,8 +180,7 @@ ObjCLanguageRuntime::GetDescriptorIterator(const ConstString &name) {
     } else {
       // Name hashes were provided, so use them to efficiently lookup name to
       // isa/descriptor
-      const uint32_t name_hash =
-          MappedHash::HashStringUsingDJB(name.GetCString());
+      const uint32_t name_hash = llvm::djbHash(name.GetStringRef());
       std::pair<HashToISAIterator, HashToISAIterator> range =
           m_hash_to_isa_map.equal_range(name_hash);
       for (HashToISAIterator range_pos = range.first; range_pos != range.second;