Feature/source loc refactor (#668)

* * Remove the need for IRHighLevelDecoration in Emit
* Use the IRLayoutDecoration for GeometryShaderPrimitiveTypeModifier

* Initial look at at variable byte encoding, and simple unit test.

* Fixing problems with comparison due to naming differences with slang/fxc.

* * More tests and perf improvements for byte encoding.
* Mechanism to detect processor and processor features in main slang header.

* Split out cpu based defines into slang-cpu-defines.h so do not polute slang.h

* Support for variable byte encoding on serialization.

* Removed unused flag.

* Fix warning.

* Fix calcMsByte32 for 0 values without using intrinsic.

* Fix a mistake in calculating maximum instruction size.

* Introduced the idea of SourceUnit.

* Small improvements around naming.
Add more functionality - including getting the HumaneLoc.

* Add support for #line default

* Compiling with new SourceLoc handling.

* Fix off by one on #line directives.

* Can use 32bits for SourceLoc. Fix serialize to use that.

* Small fixes and comment on usage.

* Premake run.

* Fix signed warning.

* Fix typo on StringSlicePool::has found in review.

1 files changed, 7 insertions, 23 deletions

diff --git a/source/slang/lexer.cpp b/source/slang/lexer.cpp
index 9ea86cc82..339d98d49 100644
--- a/source/slang/lexer.cpp
+++ b/source/slang/lexer.cpp
@@ -84,22 +84,22 @@ namespace Slang
     // Lexer
 
     void Lexer::initialize(
-        SourceFile*     inSourceFile,
+        SourceUnit*     inSourceUnit,
         DiagnosticSink* inSink,
         NamePool*       inNamePool)
     {
-        sourceFile  = inSourceFile;
+        sourceUnit  = inSourceUnit;
         sink        = inSink;
         namePool    = inNamePool;
 
-        auto content = inSourceFile->content;
+        auto content = inSourceUnit->getSourceFile()->content;
 
         begin   = content.begin();
         cursor  = content.begin();
         end     = content.end();
 
-        spellingStartLoc = inSourceFile->sourceRange.begin;
-        presumedStartLoc = spellingStartLoc;
+        // Set the start location
+        startLoc = inSourceUnit->getRange().begin;
 
         tokenFlags = TokenFlag::AtStartOfLine | TokenFlag::AfterWhitespace;
         lexerFlags = 0;
@@ -227,7 +227,7 @@ namespace Slang
                     lexer->tokenFlags |= TokenFlag::ScrubbingNeeded;
 
                     // Now try again, looking at the character after the
-                    // escaped nmewline.
+                    // escaped newline.
                     continue;
 
                 default:
@@ -333,23 +333,7 @@ namespace Slang
 
     static SourceLoc getSourceLoc(Lexer* lexer)
     {
-        return lexer->presumedStartLoc + (lexer->cursor - lexer->begin);
-    }
-
-    // Begin overriding the reported locations of tokens,
-    // based on a `#line` directives
-    void Lexer::startOverridingSourceLocations(
-        SourceLoc loc)
-    {
-        if(loc.isValid())
-        {
-            presumedStartLoc = loc;
-        }
-    }
-
-    void Lexer::stopOverridingSourceLocations()
-    {
-        presumedStartLoc = spellingStartLoc;
+        return lexer->startLoc + (lexer->cursor - lexer->begin);
     }
 
     static void lexDigits(Lexer* lexer, int base)