Improvements in -X support (#1852)

* #include an absolute path didn't work - because paths were taken to always be relative.

* Added SourceLoc handling for command line parsing.

* Fix typo in debug.

* Fix issue around the DiagnosticSink used in options parsing not having a writer available - by having DiagnosticSink parenting.

* Small rename for clarity.

* WIP extracting command line args for downstream tools.

* Unit tests/bug fixes around extracting args.

* Use DownstreamArgs in the EndToEndCompileRequest

* Passing downstream compiler options downstream.

* Fix issue with endToEndReq being nullptr.

* Fix issue with diagnostics number change.

* Small improvements to how the source line is displayed if it's too long.
Default to 120, as suggested in previous review.

* Make render test use x-args parsing and CommandArgReader.

* Added missing diagnostics.

* More DownstreamArgs to linkage so can be seen by 'components'.
Added dxc-x-arg test.

* Used combination of name and args instead of two Lists, which whilst equivalent was perhaps a little confusing.

* Added documentation for -X support.

* Added test for x-args parsing diagnostic. Improved diagnostic with list of known names.

* Fix issues from merge.

* Fix lookup for -matrix-layout-column-major in render test.

* Remove commented out line.

1 files changed, 18 insertions, 16 deletions

diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
index 9a109f9d7..613992354 100644
--- a/source/slang/slang.cpp
+++ b/source/slang/slang.cpp
@@ -731,6 +731,24 @@ Linkage::Linkage(Session* session, ASTBuilder* astBuilder, Linkage* builtinLinka
             mapNameToLoadedModules.Add(pair.Key, pair.Value);
         }
     }
+
+    {
+        RefPtr<CommandLineContext> context = new CommandLineContext;
+        m_downstreamArgs = DownstreamArgs(context);
+
+        // Add all of the possible names we allow for downstream tools
+        {
+            for (Index i = SLANG_PASS_THROUGH_NONE + 1; i < SLANG_PASS_THROUGH_COUNT_OF; ++i)
+            {
+                m_downstreamArgs.addName(TypeTextUtil::getPassThroughName(SlangPassThrough(i)));
+            }
+
+            // Generic downstream tool
+            m_downstreamArgs.addName("downstream");
+            // Generic downstream linker
+            m_downstreamArgs.addName("linker");
+        }
+    }
 }
 
 ISlangUnknown* Linkage::getInterface(const Guid& guid)
@@ -2047,22 +2065,6 @@ void EndToEndCompileRequest::init()
     m_frontEndReq = new FrontEndCompileRequest(getLinkage(), m_writers, getSink());
 
     m_backEndReq = new BackEndCompileRequest(getLinkage(), getSink());
-
-    RefPtr<CommandLineContext> context = new CommandLineContext;
-    m_downstreamArgs = DownstreamArgs(context);
-
-    // Add all of the possible names we allow for downstream tools
-    {
-        for (Index i = SLANG_PASS_THROUGH_NONE + 1; i < SLANG_PASS_THROUGH_COUNT_OF; ++i)
-        {
-            m_downstreamArgs.addName(TypeTextUtil::getPassThroughName(SlangPassThrough(i)));
-        }
-
-        // Generic downstream tool
-        m_downstreamArgs.addName("downstream");
-        // Generic downstream linker
-        m_downstreamArgs.addName("linker");
-    }
 }
 
 SlangResult EndToEndCompileRequest::executeActionsInner()