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, 9 insertions, 15 deletions

diff --git a/source/slang/slang-compiler.cpp b/source/slang/slang-compiler.cpp
index f786512d1..eecb86242 100644
--- a/source/slang/slang-compiler.cpp
+++ b/source/slang/slang-compiler.cpp
@@ -1063,14 +1063,10 @@ namespace Slang
             sourceTarget = CodeGenTarget(TypeConvertUtil::getCompileTargetFromSourceLanguage((SlangSourceLanguage)sourceLanguage));
 
             // If it's pass through we accumulate the preprocessor definitions. 
-            for (auto& define : translationUnit->compileRequest->preprocessorDefinitions)
-            {
-                preprocessorDefinitions.add(define.key, define.value);
-            }
-            for (auto& define : translationUnit->preprocessorDefinitions)
-            {
-                preprocessorDefinitions.add(define.key, define.value);
-            }
+            for (const auto& define : translationUnit->compileRequest->preprocessorDefinitions)
+                preprocessorDefinitions.add(define);
+            for (const auto& define : translationUnit->preprocessorDefinitions)
+                preprocessorDefinitions.add(define);
             
             {
                 /* TODO(JS): Not totally clear what options should be set here. If we are using the pass through - then using say the defines/includes
@@ -1148,10 +1144,8 @@ namespace Slang
             // of downstream compilation. 
             
             auto linkage = getLinkage();
-            for (auto& define : linkage->preprocessorDefinitions)
-            {
-                preprocessorDefinitions.add(define.key, define.value);
-            }
+            for (const auto& define : linkage->preprocessorDefinitions)
+                preprocessorDefinitions.add(define);
         }
 
         
@@ -1398,12 +1392,12 @@ namespace Slang
 
                 Index i = 0;
 
-                for(auto& def : preprocessorDefinitions)
+                for(const auto& [defKey, defValue] : preprocessorDefinitions)
                 {
                     auto& define = dst[i];
                     
-                    define.nameWithSig = allocator.allocate(def.key);
-                    define.value = allocator.allocate(def.value);
+                    define.nameWithSig = allocator.allocate(defKey);
+                    define.value = allocator.allocate(defValue);
 
                     ++i;
                 }