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

1 files changed, 4 insertions, 6 deletions

diff --git a/source/core/slang-memory-file-system.cpp b/source/core/slang-memory-file-system.cpp
index eabd13072..b24abc20b 100644
--- a/source/core/slang-memory-file-system.cpp
+++ b/source/core/slang-memory-file-system.cpp
@@ -171,10 +171,9 @@ SlangResult MemoryFileSystem::enumeratePathContents(const char* path, FileSystem
     ImplicitDirectoryCollector collector(canonicalPath, true);
 
     // If it is a directory, we need to see if there is anything in it
-    for (const auto& pair : m_entries)
+    for (const auto& [_, childEntry] : m_entries)
     {
-        const Entry* childEntry = &pair.value;
-        collector.addPath(childEntry->m_type, childEntry->m_canonicalPath.getUnownedSlice());
+        collector.addPath(childEntry.m_type, childEntry.m_canonicalPath.getUnownedSlice());
     }
 
     return collector.enumerate(callback, userData);
@@ -275,10 +274,9 @@ SlangResult MemoryFileSystem::remove(const char* path)
             ImplicitDirectoryCollector collector(canonicalPath);
 
             // If it is a directory, we need to see if there is anything in it
-            for (const auto& pair : m_entries)
+            for (const auto& [_, childEntry] : m_entries)
             {
-                const Entry* childEntry = &pair.value;
-                collector.addPath(childEntry->m_type, childEntry->m_canonicalPath.getUnownedSlice());
+                collector.addPath(childEntry.m_type, childEntry.m_canonicalPath.getUnownedSlice());
                 if (collector.hasContent())
                 {
                     // Directory is not empty