Support for producing SourceMap on emit (#2707)

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

* WIP source map.

* Split out handling of RttiTypeFuncs to a map type.

* Make RttiTypeFuncsMap hold default impls.

* Slightly more sophisticated RttiTypeFuncsMap

* Source map decoding.

* Fix tabs.

* Fix asserts due to negative values.

* Use less obscure mechanisms in SourceMap.

* Source map decoding.
Simplifying SourceMap usage.

* First attempt at ouputting a source map as part of emit.

* Added support for -source-map option. SourceMap is added to the artifact.

4 files changed, 116 insertions, 2 deletions

diff --git a/source/compiler-core/slang-artifact-desc-util.cpp b/source/compiler-core/slang-artifact-desc-util.cpp
index fff68738c..ee014daf0 100644
--- a/source/compiler-core/slang-artifact-desc-util.cpp
+++ b/source/compiler-core/slang-artifact-desc-util.cpp
@@ -223,7 +223,8 @@ SLANG_HIERARCHICAL_ENUM(ArtifactKind, SLANG_ARTIFACT_KIND, SLANG_ARTIFACT_KIND_E
             x(Diagnostics, Metadata) \
         x(Miscellaneous, Base) \
             x(Log, Miscellaneous) \
-            x(Lock, Miscellaneous)
+            x(Lock, Miscellaneous) \
+        x(SourceMap, Base)
 
 #define SLANG_ARTIFACT_PAYLOAD_ENTRY(TYPE, PARENT) { Index(ArtifactPayload::TYPE), Index(ArtifactPayload::PARENT), #TYPE },
 
@@ -550,6 +551,13 @@ static const KindExtension g_cpuKindExts[] =
         return ArtifactDesc::make(ArtifactKind::Assembly, ArtifactPayload::HostCPU);
     }
 
+    // TODO(JS): Unfortunately map extension is also used from output for linkage from 
+    // Visual Studio. It's used here for source map.
+    if (slice == toSlice("map"))
+    {
+        return ArtifactDesc::make(ArtifactKind::Text, ArtifactPayload::SourceMap);
+    }
+
     if (slice == toSlice("pdb"))
     {
         // Program database
@@ -621,6 +629,7 @@ static UnownedStringSlice _getPayloadExtension(ArtifactPayload payload)
         case Payload::MetalAIR:     return toSlice("air");
 
         case Payload::PdbDebugInfo: return toSlice("pdb");
+        case Payload::SourceMap:    return toSlice("map");
 
         default: break;
     }
diff --git a/source/compiler-core/slang-artifact.h b/source/compiler-core/slang-artifact.h
index df0bb21d5..c51ee729a 100644
--- a/source/compiler-core/slang-artifact.h
+++ b/source/compiler-core/slang-artifact.h
@@ -180,6 +180,8 @@ enum class ArtifactPayload : uint8_t
 
     PdbDebugInfo,   ///< PDB debug info
 
+    SourceMap,      ///< SourceMap
+
     CountOf,
 };
 
diff --git a/source/compiler-core/slang-source-map.cpp b/source/compiler-core/slang-source-map.cpp
index 413c32108..830314008 100644
--- a/source/compiler-core/slang-source-map.cpp
+++ b/source/compiler-core/slang-source-map.cpp
@@ -199,6 +199,86 @@ void SourceMap::clear()
     m_slicePool.clear();
 }
 
+void SourceMap::advanceToLine(Index nextLineIndex)
+{
+    const Count currentLineIndex = getGeneratedLineCount();
+
+    SLANG_ASSERT(nextLineIndex >= currentLineIndex);
+    
+    if (nextLineIndex <= currentLineIndex)
+    {
+        return;
+    }
+
+    const auto lastEntryIndex = m_lineEntries.getCount();
+
+    // For all the new entries they will need to point to the end 
+    m_lineStarts.setCount(nextLineIndex + 1);
+
+    Index* starts = m_lineStarts.getBuffer() + currentLineIndex;
+    const Count startsCount = nextLineIndex + 1 - currentLineIndex;
+
+    for (Index i = 0; i < startsCount; ++i)
+    {
+        starts[i] = lastEntryIndex;
+    }
+}
+
+void SourceMap::addEntry(const Entry& entry)
+{
+    m_lineEntries.add(entry);
+    ++m_lineStarts.getLast();
+
+    // Check things seem normal...
+    SLANG_ASSERT(m_lineStarts.getLast() == m_lineEntries.getCount());
+}
+
+Index SourceMap::getNameIndex(const UnownedStringSlice& slice)
+{
+    StringSlicePool::Handle handle;
+
+    if (!m_slicePool.findOrAdd(slice, handle))
+    {
+        // We know it can't possibly be used, so must be new (!)
+
+        m_names.add(handle);
+        return m_names.getCount() - 1;
+    }
+
+    // Okay, could already be in the list
+    const auto index = m_names.indexOf(handle);
+    if (index >= 0)
+    {
+        return index;
+    }
+
+    m_names.add(handle);
+    return m_names.getCount() - 1;
+}
+
+Index SourceMap::getSourceFileIndex(const UnownedStringSlice& slice)
+{
+    StringSlicePool::Handle handle;
+
+    if (!m_slicePool.findOrAdd(slice, handle))
+    {
+        // We know it can't possibly be used, so must be new (!)
+
+        m_sources.add(handle);
+        return m_sources.getCount() - 1;
+    }
+
+    // Okay, could already be in the list
+    const auto index = m_sources.indexOf(handle);
+    if (index >= 0)
+    {
+        return index;
+    }
+
+    m_sources.add(handle);
+    return m_sources.getCount() - 1;
+}
+
 SlangResult SourceMap::decode(JSONContainer* container, JSONValue root, DiagnosticSink* sink)
 {
     clear();
diff --git a/source/compiler-core/slang-source-map.h b/source/compiler-core/slang-source-map.h
index 7fd64510a..739cf1992 100644
--- a/source/compiler-core/slang-source-map.h
+++ b/source/compiler-core/slang-source-map.h
@@ -15,10 +15,19 @@
 
 namespace Slang {
 
-struct SourceMap
+struct SourceMap : public RefObject
 {
     struct Entry
     {
+        void init()
+        {
+            generatedColumn = 0;
+            sourceFileIndex = 0;
+            sourceLine = 0;
+            sourceColumn = 0;
+            nameIndex = 0;
+        }
+
         // Note! All column/line are zero indexed
         Index generatedColumn;          ///< The generated column
         Index sourceFileIndex;          ///< The index into the source name/contents
@@ -38,6 +47,20 @@ struct SourceMap
         /// Get the entries on the line
     SLANG_FORCE_INLINE ConstArrayView<Entry> getEntriesForLine(Index generatedLine) const;
     
+        /// Advance to the specified line index. 
+        /// It is an error to specify a line *before* the current line. It should either be the current 
+        /// output line or a later output line. Interveining lines will be set as empty
+    void advanceToLine(Index lineIndex);
+
+        /// Add an entry to the current line
+    void addEntry(const Entry& entry);
+
+        /// Given the slice returns the index
+    Index getSourceFileIndex(const UnownedStringSlice& slice);
+
+        /// Get the name index
+    Index getNameIndex(const UnownedStringSlice& slice);
+
         /// Clear the contents of the source map
     void clear();