Use ankerl/unordered_dense as a hashmap implementation (#3036)

* Correct namespace for getClockFrequency

* missing const

* Add missing assignment operator

* Remove unused variables

* Return correct modified variable

* Use stable hash code for file system identity

* terse static_assert

* Structured binding for map iteration

* Make (==) and getHashCode const on many structs

* Add ConstIterator for LinkedList

* Replace uses of ItemProxy::getValue with Dictionary::at

* Extract list of loads from gradientsMap before updating it

* Const correctness in type layout

* Add unordered_dense hashmap submodule

* Use wyhash or getHashCode in slang-hash.h

* refactor slang-hash.h

* Use ankerl/unordered_dense as a hashmap implementation

Notable changes:
- The subscript operator returns a reference directly to the value,
  rather than a lazy ItemProxy (pair of dict pointer and key)

slang-profile time (95% over 10 runs):

- Before: 6.3913906 (±0.0746)
- After:  5.9276123 (±0.0964)

* 64 bit hash for strings

So they have the same hash as char buffers with the same contents

* Narrowing warnings for gcc to match msvc

* revert back to c++17

* Correct c++ version for msvc

* Use path to unordered_dense which keeps tests happy

* Do not assign to and read from map in same expression

* Remove redundant map operations in primal-hoist

* Split out stable hash functions into slang-stable-hash.h

* 64 bit hash by default

* regenerate vs projects

* Correct return type from HashSetBase::getCount()

* correct width for call to Dictionary::reserve

* Use stable hash for obfuscated module ids

* Signed int for reserve

* clearer variable naming

* Parameterize Dictionary on hash and equality functors

* Allow heterogenous lookup for Dictionary

* missing const

* Use set over operator[] in some places

* Remove unused function

* s/at/getValue

8 files changed, 21 insertions, 23 deletions

diff --git a/tools/gfx/debug-layer/debug-shader-object.h b/tools/gfx/debug-layer/debug-shader-object.h
index 9f368a2c1..b5a268892 100644
--- a/tools/gfx/debug-layer/debug-shader-object.h
+++ b/tools/gfx/debug-layer/debug-shader-object.h
@@ -12,13 +12,13 @@ namespace debug
 struct ShaderOffsetKey
 {
     ShaderOffset offset;
-    bool operator==(ShaderOffsetKey other)
+    bool operator==(ShaderOffsetKey other) const
     {
         return offset.bindingArrayIndex == other.offset.bindingArrayIndex &&
             offset.bindingRangeIndex == other.offset.bindingRangeIndex &&
             offset.uniformOffset == other.offset.uniformOffset;
     }
-    Slang::HashCode getHashCode()
+    Slang::HashCode getHashCode() const
     {
         return Slang::combineHash(
             (Slang::HashCode)offset.uniformOffset,
diff --git a/tools/gfx/renderer-shared.cpp b/tools/gfx/renderer-shared.cpp
index 99188233a..1e4cbb2f4 100644
--- a/tools/gfx/renderer-shared.cpp
+++ b/tools/gfx/renderer-shared.cpp
@@ -3,6 +3,7 @@
 #include "core/slang-io.h"
 #include "core/slang-token-reader.h"
 
+#include "../../source/core/slang-stable-hash.h"
 #include "../../source/core/slang-file-system.h"
 
 #include "../../slang.h"
diff --git a/tools/gfx/renderer-shared.h b/tools/gfx/renderer-shared.h
index 38aa775be..32aa22b48 100644
--- a/tools/gfx/renderer-shared.h
+++ b/tools/gfx/renderer-shared.h
@@ -1043,7 +1043,7 @@ struct ComponentKey
     Slang::UnownedStringSlice typeName;
     Slang::ShortList<ShaderComponentID> specializationArgs;
     Slang::HashCode hash;
-    Slang::HashCode getHashCode()
+    Slang::HashCode getHashCode() const
     {
         return hash;
     }
@@ -1060,7 +1060,7 @@ struct PipelineKey
     PipelineStateBase* pipeline;
     Slang::ShortList<ShaderComponentID> specializationArgs;
     Slang::HashCode hash;
-    Slang::HashCode getHashCode()
+    Slang::HashCode getHashCode() const
     {
         return hash;
     }
@@ -1070,7 +1070,7 @@ struct PipelineKey
         for (auto& arg : specializationArgs)
             hash = Slang::combineHash(hash, arg);
     }
-    bool operator==(const PipelineKey& other)
+    bool operator==(const PipelineKey& other) const
     {
         if (pipeline != other.pipeline)
             return false;
@@ -1090,12 +1090,12 @@ struct OwningComponentKey
     Slang::String typeName;
     Slang::ShortList<ShaderComponentID> specializationArgs;
     Slang::HashCode hash;
-    Slang::HashCode getHashCode()
+    Slang::HashCode getHashCode() const
     {
         return hash;
     }
     template<typename KeyType>
-    bool operator==(const KeyType& other)
+    bool operator==(const KeyType& other) const
     {
         if (typeName != other.typeName)
             return false;
diff --git a/tools/slang-cpp-extractor/node.cpp b/tools/slang-cpp-extractor/node.cpp
index b606e4edf..1189e3815 100644
--- a/tools/slang-cpp-extractor/node.cpp
+++ b/tools/slang-cpp-extractor/node.cpp
@@ -316,7 +316,7 @@ void ScopeNode::addChild(Node* child)
 
 Node* ScopeNode::findChild(const UnownedStringSlice& name) const
 {
-    Node** nodePtr = m_childMap.tryGetValue(name);
+    Node* const* nodePtr = m_childMap.tryGetValue(name);
     if (nodePtr)
     {
         return *nodePtr;
diff --git a/tools/slang-lookup-generator/lookup-generator-main.cpp b/tools/slang-lookup-generator/lookup-generator-main.cpp
index 796275e4a..cb1c15dd3 100644
--- a/tools/slang-lookup-generator/lookup-generator-main.cpp
+++ b/tools/slang-lookup-generator/lookup-generator-main.cpp
@@ -103,12 +103,11 @@ static HashFindResult minimalPerfectHash(const List<String>& ss, HashParams& has
     const auto hash = [&](const String& s, const HashCode64 salt = 0) -> UInt32
     {
         //
-        // The current getStableHashCode32 is susceptible to patterns of
-        // collisions causing the search to fail for the SPIR-V opnames
-        //
-        // getStableHashCode64 is better, although it still performs poorly on
-        // short strings, taking over 300000 iterations to diverge on "Ceil"
-        // and "FMix" (and place them in already unoccupied slots)!
+        // The current getStableHashCode is susceptible to patterns of
+        // collisions causing the search to fail for the SPIR-V opnames; it
+        // performs poorly on short strings, taking over 300000 iterations to
+        // diverge on "Ceil" and "FMix" (and place them in already unoccupied
+        // slots)!
         //
         // Use FNV Hash here which seem perform much better on these short inputs
         // https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function
diff --git a/tools/slang-profile/slang-profile-main.cpp b/tools/slang-profile/slang-profile-main.cpp
index 2bc97548f..7cf6cb6f8 100644
--- a/tools/slang-profile/slang-profile-main.cpp
+++ b/tools/slang-profile/slang-profile-main.cpp
@@ -17,7 +17,7 @@ SlangResult innerMain(int argc, char** argv)
 
     // Time the creation of the session
     {
-        const auto startTick = ProcessUtil::getClockTick();
+        const auto startTick = Process::getClockTick();
 
         for (Int i = 0; i < 32; ++i)
         {
@@ -25,9 +25,9 @@ SlangResult innerMain(int argc, char** argv)
             slangSession.attach(spCreateSession(nullptr));
         }
 
-        const auto endTick = ProcessUtil::getClockTick();
+        const auto endTick = Process::getClockTick();
 
-        printf("Ticks %f\n", double(endTick - startTick) / ProcessUtil::getClockFrequency());
+        printf("Ticks %f\n", double(endTick - startTick) / Process::getClockFrequency());
         return SLANG_OK;
     }
 
diff --git a/tools/slang-test/slang-test-main.cpp b/tools/slang-test/slang-test-main.cpp
index 1359b4474..95ef4d55d 100644
--- a/tools/slang-test/slang-test-main.cpp
+++ b/tools/slang-test/slang-test-main.cpp
@@ -3661,9 +3661,9 @@ bool testCategoryMatches(
     TestCategory*                           categoryToMatch,
     const Dictionary<TestCategory*, TestCategory*>& categorySet)
 {
-    for( auto item : categorySet )
+    for( const auto& [_, category] : categorySet )
     {
-        if(testCategoryMatches(categoryToMatch, item.value))
+        if(testCategoryMatches(categoryToMatch, category))
             return true;
     }
     return false;
diff --git a/tools/test-server/test-server-main.cpp b/tools/test-server/test-server-main.cpp
index 904a8db20..b37f8b29f 100644
--- a/tools/test-server/test-server-main.cpp
+++ b/tools/test-server/test-server-main.cpp
@@ -185,10 +185,8 @@ SlangResult TestServer::init(int argc, const char* const* argv)
 
 TestServer::~TestServer()
 {
-    for (auto& pair : m_unitTestModules)
-    {
-        pair.value->destroy();
-    }
+    for (auto& [_, value] : m_unitTestModules)
+        value->destroy();
 }
 
 slang::IGlobalSession* TestServer::getOrCreateGlobalSession()