Add -dump-module command to slangc

The new -dump-module command to slangc will load and disassemble a slang module, similar to what would be seen by the -dump-ir command, except that -dump-ir tells slangc to print IR as it performs some compilation command. That is, -dump-ir requires
some larger compilation task.

-dump-module on the otherhand requires no additional goal and will simply load a module and print its IR to stdout independently from other compilation steps.

Its intended purpose is to inspect .slang-module files on disk.
It can also be used on .slang files which will be parsed and lowered
if slang does not find an associated ".slang-module" version of the
module on disk.

The compilation API is extended with a new IModule::disassemble()
method which retrieves the string representation of the dumped IR.

Closes shader-slang#6599

Author: cheneym2

include/slang.h

@@ -1015,6 +1015,7 @@ typedef uint32_t SlangSizeT;
         SaveGLSLModuleBinSource,
 
         SkipDownstreamLinking, // bool, experimental
+        DumpModule,
         CountOf,
     };
 
@@ -4417,6 +4418,11 @@ struct IModule : public IComponentType
     virtual SLANG_NO_THROW char const* SLANG_MCALL getDependencyFilePath(SlangInt32 index) = 0;
 
     virtual SLANG_NO_THROW DeclReflection* SLANG_MCALL getModuleReflection() = 0;
+
+    /** Disassemble a module.
+     */
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL disassemble(
+        slang::IBlob** outDisassembledBlob) = 0;    
 };
 
     #define SLANG_UUID_IModule IModule::getTypeGuid()

source/slang-record-replay/record/slang-module.cpp

@@ -244,4 +244,12 @@ IEntryPointRecorder* ModuleRecorder::getEntryPointRecorder(slang::IEntryPoint* e
         return result.detach();
     }
 }
+
+SlangResult ModuleRecorder::disassemble(ISlangBlob** outBlob)
+{
+    // No need to record this call as it is just a query.
+    slangRecordLog(LogLevel::Verbose, "%s\n", __PRETTY_FUNCTION__);
+    auto res = m_actualModule->disassemble(outBlob);    
+    return res;
+}
 } // namespace SlangRecord

source/slang-record-replay/record/slang-module.h

@@ -56,6 +56,7 @@ class ModuleRecorder : public IModuleRecorder, public IComponentTypeRecorder
         ISlangBlob** outDiagnostics) override;
     virtual SLANG_NO_THROW SlangInt32 SLANG_MCALL getDependencyFileCount() override;
     virtual SLANG_NO_THROW char const* SLANG_MCALL getDependencyFilePath(SlangInt32 index) override;
+    virtual SLANG_NO_THROW SlangResult SLANG_MCALL disassemble(slang::IBlob** outDisassembly) override;
 
     // Interfaces for `IComponentType`
     virtual SLANG_NO_THROW slang::ISession* SLANG_MCALL getSession() override

source/slang/slang-compiler.h

@@ -1832,6 +1832,19 @@ class Module : public ComponentType, public slang::IModule
 
     // Source files that have been pulled into the module with `__include`.
     Dictionary<SourceFile*, FileDecl*> m_mapSourceFileToFileDecl;
+
+    public:
+    SLANG_NO_THROW SlangResult SLANG_MCALL disassemble(
+        slang::IBlob** outDisassembledBlob) override
+        {
+            if (!outDisassembledBlob)
+                return SLANG_E_INVALID_ARG;
+            String disassembly;
+            this->getIRModule()->getModuleInst()->dump(disassembly);
+            auto blob = StringUtil::createStringBlob(disassembly);
+            *outDisassembledBlob = blob.detach();
+            return SLANG_OK;
+        }
 };
 typedef Module LoadedModule;
 

source/slang/slang-ir.cpp

@@ -8950,24 +8950,33 @@ void IRInst::addBlock(IRBlock* block)
     block->insertAtEnd(this);
 }
 
-void IRInst::dump()
-{
+void IRInst::dump(String &outStr)
+{    
+    StringBuilder sb;        
+
     if (auto intLit = as<IRIntLit>(this))
     {
-        std::cout << intLit->getValue() << std::endl;
+        sb << intLit->getValue();
     }
     else if (auto stringLit = as<IRStringLit>(this))
     {
-        std::cout << stringLit->getStringSlice().begin() << std::endl;
+        sb << stringLit->getStringSlice();            
     }
     else
-    {
-        StringBuilder sb;
+    {        
         IRDumpOptions options;
         StringWriter writer(&sb, Slang::WriterFlag::AutoFlush);
         dumpIR(this, options, nullptr, &writer);
-        std::cout << sb.toString().begin() << std::endl;
     }
+
+    outStr = sb.toString();
+}
+
+void IRInst::dump()
+{
+    String s;
+    dump(s);
+    std::cout << s.begin() << std::endl;
 }
 } // namespace Slang
 

source/slang/slang-ir.h

@@ -813,10 +813,14 @@ struct IRInst
     ///
     void _insertAt(IRInst* inPrev, IRInst* inNext, IRInst* inParent);
 
-    /// Print the IR to stdout for debugging purposes
+    /// Print the IR to stdout for debugging purposes.
     ///
     void dump();
 
+    /// Print the IR to a string for debugging purposes.
+    ///
+    void dump(String &outStr);
+
     /// Insert a basic block at the end of this func/code containing inst.
     void addBlock(IRBlock* block);
 

source/slang/slang-options.cpp

@@ -802,7 +802,8 @@ void initCommandOptions(CommandOptions& options)
         {OptionKind::VerifyDebugSerialIr,
          "-verify-debug-serial-ir",
          nullptr,
-         "Verify IR in the front-end."}};
+         "Verify IR in the front-end."},
+        {OptionKind::DumpModule, "-dump-module", nullptr, "Disassemble and print the module IR."}};
     _addOptions(makeConstArrayView(debuggingOpts), options);
 
     /* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Experimental !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! */
@@ -2947,6 +2948,70 @@ SlangResult OptionsParser::_parse(int argc, char const* const* argv)
                 Int index = 0;
                 SLANG_RETURN_ON_FAIL(_expectInt(arg, index));
                 linkage->m_optionSet.add(OptionKind::BindlessSpaceIndex, (int)index);
+                break;
+            }
+        case OptionKind::DumpModule:
+            {
+                CommandLineArg fileName;
+                SLANG_RETURN_ON_FAIL(m_reader.expectArg(fileName));                
+                auto desc = slang::SessionDesc();
+                ComPtr<slang::ISession> session;
+                m_session->createSession(desc, session.writeRef());
+                ComPtr<slang::IBlob> diagnostics;
+
+                // Coerce Slang to load from the given file, without letting it automatically
+                // choose .slang-module files over .slang files.  
+                // First try to load as source string, and fall back to loading as an IR Blob.
+                // Avoid guessing based on filename or inspect the file contents.
+                FILE* file = fopen(fileName.value.getBuffer(), "rb");
+                fseek(file, 0, SEEK_END);
+                size_t size = ftell(file);
+                fseek(file, 0, SEEK_SET);
+                std::vector<char> buffer(size+1);
+                fread(buffer.data(), 1, size, file);
+                buffer[size] = 0;
+                fclose(file);
+                
+                ComPtr<slang::IModule> module;
+                module = session->loadModuleFromSourceString("module", "path", buffer.data(), diagnostics.writeRef());
+                if (!module)
+                {
+                    // Load buffer as an IR blob
+                    ComPtr<slang::IBlob> blob;
+                    blob = RawBlob::create(buffer.data(), size);
+                    
+                    module = session->loadModuleFromIRBlob(
+                        "module",
+                        "path",
+                        blob,
+                        diagnostics.writeRef());
+                }
+                
+                if (module)
+                {
+                    ComPtr<slang::IBlob> disassemblyBlob;
+                    if (SLANG_FAILED(module->disassemble(disassemblyBlob.writeRef())))
+                    {
+                        m_sink->diagnose(arg.loc, Diagnostics::cannotDisassemble, fileName.value);
+                        return SLANG_FAIL;
+                    }
+                    else
+                    {
+                        m_sink->diagnoseRaw(Severity::Note, (const char*)disassemblyBlob->getBufferPointer());                        
+                    }
+                }
+                else
+                {
+                    if (diagnostics)
+                    {
+                        m_sink->diagnoseRaw(
+                            Severity::Error,
+                            (const char*)diagnostics->getBufferPointer());
+                    }                    
+                    return SLANG_FAIL;
+                }
+                
+                
                 break;
             }
         default:

tests/ir/dump-module.slang

@@ -0,0 +1,53 @@
+// This tests slangc's -dump-module command.
+// Dumping ".slang" should mean just that, and it should not automatically load up
+// a ".slang-module" when available, because the intent of the -dump-module command
+// is to see the file you requested. If there's a bug in slang-module output, it's
+// important that -dump-module looks at the specific file you requested.
+
+//TEST:COMPILE: tests/ir/dump-module.slang -o tests/ir/dump-module.slang-module -target spirv -embed-downstream-ir
+
+//TEST:SIMPLE(filecheck=CHECK1): -dump-module tests/ir/dump-module.slang-module
+//TEST:SIMPLE(filecheck=CHECK2): -dump-module tests/ir/dump-module.slang
+
+module "export-library-generics";
+
+public cbuffer Constants {
+    public float x;
+    public float y;
+}
+
+interface MyInterface
+{
+    int myMethod(int a);
+}
+
+struct MyType : MyInterface
+{
+    int myMethod(int a)
+    {
+        return a * 3;
+    }
+}
+
+int genericFunc<T: MyInterface>(T arg)
+{
+    return arg.myMethod(3);
+}
+
+public int normalFuncUsesGeneric(int a)
+{
+    MyType obj;
+    return genericFunc(obj);
+}
+
+public int normalFunc(int a, float b)
+{
+    return a - floor(b);
+}
+
+// CHECK1:EmbeddedDownstreamIR(6 : Int,
+// CHECK1:               OpCapability Linkage
+
+// CHECK2-NOT:EmbeddedDownstreamIR(6 : Int,
+// CHECK2-NOT:               OpCapability Linkage
+