Use std::unordered_map instead of std::map

In theory it should be faster.

Change-Id: Ibf6ce8c5dced5a075b57f89ce6e2d5ed1c5d6be7
Reviewed-by: hjk <hjk@qt.io>

src/libs/3rdparty/cplusplus/FullySpecifiedType.cpp

@@ -200,6 +200,11 @@ bool FullySpecifiedType::operator < (const FullySpecifiedType &other) const
     return _type < other._type;
 }
 
+size_t FullySpecifiedType::hash() const
+{
+    return std::hash<Type *>()(_type) ^ std::hash<unsigned>()(_flags);
+}
+
 FullySpecifiedType FullySpecifiedType::simplified() const
 {
     if (const ReferenceType *refTy = type()->asReferenceType())

src/libs/3rdparty/cplusplus/FullySpecifiedType.h

@@ -103,6 +103,8 @@ public:
     bool operator != (const FullySpecifiedType &other) const;
     bool operator < (const FullySpecifiedType &other) const;
 
+    size_t hash() const;
+
     bool match(const FullySpecifiedType &otherTy, Matcher *matcher = nullptr) const;
 
     FullySpecifiedType simplified() const;

src/libs/3rdparty/cplusplus/Name.cpp

@@ -25,6 +25,7 @@
 #include "NameVisitor.h"
 
 #include <cstring>
+#include <string_view>
 
 using namespace CPlusPlus;
 
@@ -77,22 +78,33 @@ bool Name::match(const Name *other, Matcher *matcher) const
     return Matcher::match(this, other, matcher);
 }
 
-bool Name::Compare::operator()(const Name *name, const Name *other) const
+bool Name::Equals::operator()(const Name *name, const Name *other) const
 {
-    if (name == nullptr)
-        return other != nullptr;
-    if (other == nullptr)
-        return false;
     if (name == other)
+        return true;
+    if (name == nullptr || other == nullptr)
         return false;
 
     const Identifier *id = name->identifier();
     const Identifier *otherId = other->identifier();
 
-    if (id == nullptr)
-        return otherId != nullptr;
-    if (otherId == nullptr)
+    if (id == otherId)
+        return true;
+    if (id == nullptr || otherId == nullptr)
         return false;
 
-    return std::strcmp(id->chars(), otherId->chars()) < 0;
+    return std::strcmp(id->chars(), otherId->chars()) == 0;
+}
+
+size_t Name::Hash::operator()(const Name *name) const
+{
+    if (name == nullptr)
+        return 0;
+
+    const Identifier *id = name->identifier();
+
+    if (id == nullptr)
+        return 0;
+
+    return std::hash<std::string_view>()(std::string_view(id->chars()));
 }

src/libs/3rdparty/cplusplus/Name.h

@@ -59,9 +59,12 @@ public:
     bool match(const Name *other, Matcher *matcher = nullptr) const;
 
 public:
-    struct Compare {
+    struct Equals {
         bool operator()(const Name *name, const Name *other) const;
     };
+    struct Hash {
+        size_t operator()(const Name *name) const;
+    };
 
 protected:
     virtual void accept0(NameVisitor *visitor) const = 0;

src/libs/3rdparty/cplusplus/Names.cpp

@@ -24,6 +24,7 @@
 #include "Literals.h"
 #include <algorithm>
 #include <cstring>
+#include <string_view>
 
 using namespace CPlusPlus;
 
@@ -106,38 +107,48 @@ int TemplateNameId::templateArgumentCount() const
 const TemplateArgument &TemplateNameId::templateArgumentAt(int index) const
 { return _templateArguments[index]; }
 
-bool TemplateNameId::Compare::operator()(const TemplateNameId *name,
+bool TemplateNameId::Equals::operator()(const TemplateNameId *name,
                                         const TemplateNameId *other) const
 {
-    if (name == nullptr)
-        return other != nullptr;
-    if (other == nullptr)
-        return false;
     if (name == other)
+        return true;
+    if (name == nullptr || other == nullptr)
         return false;
 
     const Identifier *id = name->identifier();
     const Identifier *otherId = other->identifier();
 
-    if (id == nullptr)
-        return otherId != nullptr;
-    if (otherId == nullptr)
+    if (!id != !otherId) // mimic logical xor (id == nullptr ^^ otherId == nullptr)
         return false;
 
-    const int c = std::strcmp(id->chars(), otherId->chars());
+    const int c = id ? std::strcmp(id->chars(), otherId->chars()) : 0; // 0 if both are nullptr
     if (c == 0) {
         // we have to differentiate TemplateNameId with respect to specialization or instantiation
         if (name->isSpecialization() == other->isSpecialization()) {
-            return std::lexicographical_compare(name->firstTemplateArgument(),
+            return std::equal(name->firstTemplateArgument(),
                               name->lastTemplateArgument(),
                               other->firstTemplateArgument(),
                               other->lastTemplateArgument());
-        } else {
-            return name->isSpecialization();
         }
     }
+    return false;
+}
 
-    return c < 0;
+size_t TemplateNameId::Hash::operator()(const TemplateNameId *name) const
+{
+    if (name == nullptr)
+        return 0;
+
+    const Identifier *id = name->identifier();
+
+    size_t hash = id ? std::hash<std::string_view>()(std::string_view(id->chars())) : 0;
+    hash ^= name->isSpecialization() ? 0x1 : 0x0;
+    std::for_each(name->firstTemplateArgument(),
+                  name->lastTemplateArgument(),
+                  [&hash](const TemplateArgument &ta) {
+        hash ^= ta.hash();
+    });
+    return hash;
 }
 
 OperatorNameId::OperatorNameId(Kind kind)

src/libs/3rdparty/cplusplus/Names.h

@@ -113,6 +113,11 @@ public:
 
     bool match(const TemplateArgument &otherTy, Matcher *matcher = nullptr) const;
 
+    size_t hash() const
+    {
+        return _expressionTy.hash() ^ std::hash<const NumericLiteral *>()(_numericLiteral);
+    }
+
 private:
     FullySpecifiedType _expressionTy;
     const NumericLiteral *_numericLiteral = nullptr;
@@ -145,10 +150,13 @@ public:
     TemplateArgumentIterator lastTemplateArgument() const { return _templateArguments.end(); }
     bool isSpecialization() const { return _isSpecialization; }
 
-    // Comparator needed to distinguish between two different TemplateNameId(e.g.:used in std::map)
-    struct Compare {
+    // Comparator needed to distinguish between two different TemplateNameId(e.g.:used in std::unordered_map)
+    struct Equals {
         bool operator()(const TemplateNameId *name, const TemplateNameId *other) const;
     };
+    struct Hash {
+        size_t operator()(const TemplateNameId *name) const;
+    };
 
 protected:
     void accept0(NameVisitor *visitor) const override;

src/libs/3rdparty/cplusplus/Templates.h

@@ -60,7 +60,7 @@ public:
 private:
     Control *_control;
     Subst *_previous;
-    std::map<const Name *, FullySpecifiedType, Name::Compare> _map;
+    std::unordered_map<const Name *, FullySpecifiedType, Name::Hash, Name::Equals> _map;
 };
 
 class CPLUSPLUS_EXPORT CloneType: protected TypeVisitor

src/libs/cplusplus/LookupContext.h

@@ -89,8 +89,8 @@ public:
     Class *rootClass() const { return _rootClass; }
 
 private:
-    typedef std::map<const Name *, ClassOrNamespace *, Name::Compare> Table;
-    typedef std::map<const TemplateNameId *, ClassOrNamespace *, TemplateNameId::Compare> TemplateNameIdTable;
+    typedef std::unordered_map<const Name *, ClassOrNamespace *, Name::Hash, Name::Equals> Table;
+    typedef std::unordered_map<const TemplateNameId *, ClassOrNamespace *, TemplateNameId::Hash, TemplateNameId::Equals> TemplateNameIdTable;
     typedef QHash<const AnonymousNameId *, ClassOrNamespace *> Anonymouses;
 
     /// \internal