Support for PDB output from DXC (#2693)

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

* Add versioning to CompileOptions for DownstreamCompiler so we can add new options without breaking binary interface.

* Add support for debug info format to API/command line processing.

* Small simplification.

* Add support for adding PDB output from a compilation.

* Use builtin offset of directly.

* Fix typo in debug.

5 files changed, 61 insertions, 4 deletions

diff --git a/source/compiler-core/slang-artifact-desc-util.cpp b/source/compiler-core/slang-artifact-desc-util.cpp
index 7e274794f..fff68738c 100644
--- a/source/compiler-core/slang-artifact-desc-util.cpp
+++ b/source/compiler-core/slang-artifact-desc-util.cpp
@@ -219,6 +219,7 @@ SLANG_HIERARCHICAL_ENUM(ArtifactKind, SLANG_ARTIFACT_KIND, SLANG_ARTIFACT_KIND_E
         x(CompileResults, Base) \
         x(Metadata, Base) \
             x(DebugInfo, Metadata) \
+                x(PdbDebugInfo, DebugInfo) \
             x(Diagnostics, Metadata) \
         x(Miscellaneous, Base) \
             x(Log, Miscellaneous) \
@@ -549,6 +550,12 @@ static const KindExtension g_cpuKindExts[] =
         return ArtifactDesc::make(ArtifactKind::Assembly, ArtifactPayload::HostCPU);
     }
 
+    if (slice == toSlice("pdb"))
+    {
+        // Program database
+        return ArtifactDesc::make(ArtifactKind::Assembly, ArtifactPayload::PdbDebugInfo);
+    }
+
     for (const auto& kindExt : g_cpuKindExts)
     {
         if (slice == kindExt.ext)
@@ -613,6 +620,8 @@ static UnownedStringSlice _getPayloadExtension(ArtifactPayload payload)
         
         case Payload::MetalAIR:     return toSlice("air");
 
+        case Payload::PdbDebugInfo: return toSlice("pdb");
+
         default: break;
     }
     return UnownedStringSlice();
diff --git a/source/compiler-core/slang-artifact.h b/source/compiler-core/slang-artifact.h
index 222b902a5..df0bb21d5 100644
--- a/source/compiler-core/slang-artifact.h
+++ b/source/compiler-core/slang-artifact.h
@@ -178,6 +178,8 @@ enum class ArtifactPayload : uint8_t
     Log,            ///< Log file
     Lock,           ///< Typically some kind of 'lock' file. Contents is typically not important.
 
+    PdbDebugInfo,   ///< PDB debug info
+
     CountOf,
 };
 
diff --git a/source/compiler-core/slang-downstream-compiler.h b/source/compiler-core/slang-downstream-compiler.h
index b1f1b7b11..3cd27138f 100644
--- a/source/compiler-core/slang-downstream-compiler.h
+++ b/source/compiler-core/slang-downstream-compiler.h
@@ -252,6 +252,9 @@ struct DownstreamCompileOptions
     /// NOTE! Not all downstream compilers can use the fileSystemExt/sourceManager. This option will be ignored in those scenarios.
     ISlangFileSystemExt* fileSystemExt = nullptr;
     SourceManager* sourceManager = nullptr;
+
+    // The debug info format to use. 
+    SlangDebugInfoFormat m_debugInfoFormat = SLANG_DEBUG_INFO_FORMAT_DEFAULT;
 };
 
 #define SLANG_ALIAS_DEPRECIATED_VERSION(name, id, firstField, lastField) \
diff --git a/source/compiler-core/slang-dxc-compiler.cpp b/source/compiler-core/slang-dxc-compiler.cpp
index 9df2a4f3f..248d8d118 100644
--- a/source/compiler-core/slang-dxc-compiler.cpp
+++ b/source/compiler-core/slang-dxc-compiler.cpp
@@ -451,6 +451,8 @@ SlangResult DXCDownstreamCompiler::compile(const CompileOptions& inOptions, IArt
             break;
     }
 
+
+
     switch (options.optimizationLevel)
     {
         default:
@@ -549,7 +551,7 @@ SlangResult DXCDownstreamCompiler::compile(const CompileOptions& inOptions, IArt
 
     DxcIncludeHandler includeHandler(&searchDirectories, options.fileSystemExt, options.sourceManager);
 
-    ComPtr<IDxcOperationResult> dxcResult;
+    ComPtr<IDxcOperationResult> dxcOperationResult;
     SLANG_RETURN_ON_FAIL(dxcCompiler->Compile(dxcSourceBlob,
         wideSourcePath.begin(),
         wideEntryPointName.begin(),
@@ -559,13 +561,13 @@ SlangResult DXCDownstreamCompiler::compile(const CompileOptions& inOptions, IArt
         nullptr,            // `#define`s
         0,                  // `#define` count
         &includeHandler,    // `#include` handler
-        dxcResult.writeRef()));
+        dxcOperationResult.writeRef()));
 
     auto diagnostics = ArtifactDiagnostics::create();
     
     ComPtr<IDxcBlob> dxcResultBlob;
 
-    SLANG_RETURN_ON_FAIL(_handleOperationResult(dxcResult, diagnostics, dxcResultBlob));
+    SLANG_RETURN_ON_FAIL(_handleOperationResult(dxcOperationResult, diagnostics, dxcResultBlob));
 
     // If we have libraries then we need to link...
     if (libraries.getCount())
@@ -629,6 +631,11 @@ SlangResult DXCDownstreamCompiler::compile(const CompileOptions& inOptions, IArt
         ComPtr<IDxcBlob> linkedBlob;
         SLANG_RETURN_ON_FAIL(_handleOperationResult(linkDxcResult, diagnostics, linkedBlob));
 
+        // When we've linked we make that the overall operation result
+        // As presumably it can contain pdb and perhaps other information
+        dxcOperationResult = linkDxcResult;
+
+        // Set the result blob
         dxcResultBlob = linkedBlob;
     }
 
@@ -639,6 +646,42 @@ SlangResult DXCDownstreamCompiler::compile(const CompileOptions& inOptions, IArt
         artifact->addRepresentationUnknown((ISlangBlob*)dxcResultBlob.get());
     }
 
+    // If asking for PDB extract it.
+    if (options.m_debugInfoFormat == SLANG_DEBUG_INFO_FORMAT_PDB)
+    {
+        ComPtr<IDxcResult> dxcResult;
+        if (SLANG_SUCCEEDED(dxcOperationResult->QueryInterface(dxcResult.writeRef())))
+        {
+            if (dxcResult->HasOutput(DXC_OUT_PDB))
+            {
+                ComPtr<IDxcBlob> pdbBlob;
+                ComPtr<IDxcBlobWide> nameBlob;
+
+                if (SLANG_SUCCEEDED(dxcResult->GetOutput(DXC_OUT_PDB, __uuidof(pdbBlob), (void**)pdbBlob.writeRef(), nameBlob.writeRef())))
+                {
+                    auto pdbArtifact = ArtifactUtil::createArtifact(ArtifactDesc::make(ArtifactDesc::Kind::BinaryFormat, ArtifactDesc::Payload::PdbDebugInfo));
+
+                    if (nameBlob)
+                    {
+                        const auto wideName = (const WCHAR*)nameBlob->GetBufferPointer();
+
+                        const auto name = String::fromWString(wideName);
+                        if (name.getLength())
+                        {
+                            // Set the name on the artifact. This is the name that must be used for the PDB to be loadable as a file by other tooling.
+                            pdbArtifact->setName(name.getBuffer());
+                        }
+                    }
+
+                    pdbArtifact->addRepresentationUnknown((ISlangBlob*)pdbBlob.get());
+
+                    // Associate it
+                    artifact->addAssociated(pdbArtifact);
+                }
+            }
+        }
+    }
+
     *outArtifact = artifact.detach();
     return SLANG_OK;
 }
diff --git a/source/compiler-core/slang-visual-studio-compiler-util.cpp b/source/compiler-core/slang-visual-studio-compiler-util.cpp
index 2d5b37c50..32b4d7f25 100644
--- a/source/compiler-core/slang-visual-studio-compiler-util.cpp
+++ b/source/compiler-core/slang-visual-studio-compiler-util.cpp
@@ -66,7 +66,7 @@ static void _addFile(const String& path, const ArtifactDesc& desc, IOSFileArtifa
     if (flags & ProductFlag::Debug)
     {
         // TODO(JS): Could try and determine based on debug information
-        _addFile(modulePath + ".pdb", ArtifactDesc::make(ArtifactKind::BinaryFormat, ArtifactPayload::DebugInfo, targetDesc), lockFile, outArtifacts);
+        _addFile(modulePath + ".pdb", ArtifactDesc::make(ArtifactKind::BinaryFormat, ArtifactPayload::PdbDebugInfo, targetDesc), lockFile, outArtifacts);
     }
 
     return SLANG_OK;