IR: Add SPIR-V disassembly for embedded downstream IR dumps (#6529)

* IR: Add SPIR-V disassembly for embedded downstream IR dumps

When dumping IR that contains embedded downstream SPIR-V code (via
EmbeddedDownstreamIR instructions), display the disassembled SPIR-V
instead of just showing "<binary blob>".

This CL also does:
- Adds a new interface for disassembly and get result.
- Modify export-library-generics.slang test test to check for the
  disassembled SPIR-V

Fixes #6513

* Add module-dual-target-verify test

Fixes #6517
Adds a new test to verify that dxil and spirv targets are stored
separately in the precompiled blob.

* Fix review comments from cheneym2

* format code

---------

Co-authored-by: slangbot <186143334+slangbot@users.noreply.github.com>

1 files changed, 77 insertions, 0 deletions

diff --git a/source/slang/slang-ir.cpp b/source/slang/slang-ir.cpp
index 72313217b..92e51fe3b 100644
--- a/source/slang/slang-ir.cpp
+++ b/source/slang/slang-ir.cpp
@@ -7117,6 +7117,76 @@ void dumpIRGeneric(IRDumpContext* context, IRGeneric* witnessTable)
     dump(context, "}\n");
 }
 
+static void dumpEmbeddedDownstream(IRDumpContext* context, IRInst* inst)
+{
+    auto targetInst = inst->getOperand(0);
+    auto blobInst = inst->getOperand(1);
+
+    // Get the target value
+    auto targetLit = as<IRIntLit>(targetInst);
+    if (!targetLit)
+    {
+        dump(context, "EmbeddedDownstreamIR(invalid target)");
+        return;
+    }
+
+    // Get the blob
+    auto blobLitInst = as<IRBlobLit>(blobInst);
+    if (!blobLitInst)
+    {
+        dump(context, "EmbeddedDownstreamIR(invalid blob)");
+        return;
+    }
+
+    dump(context, "EmbeddedDownstreamIR(");
+    dump(context, targetLit->getValue());
+    dump(context, " : Int, ");
+
+    // If target is SPIR-V (6), disassemble the blob
+    if (targetLit->getValue() == (IRIntegerValue)CodeGenTarget::SPIRV)
+    {
+        auto blob = blobLitInst->getStringSlice();
+        const uint32_t* spirvCode = (const uint32_t*)blob.begin();
+        const size_t spirvWordCount = blob.getLength() / sizeof(uint32_t);
+
+        // Get the compiler from the session through the module
+        auto module = inst->getModule();
+        auto session = module->getSession();
+        IDownstreamCompiler* compiler =
+            session->getOrLoadDownstreamCompiler(PassThroughMode::SpirvDis, nullptr);
+
+        if (compiler)
+        {
+            // Use glslang interface to disassemble with string output
+            String disassemblyOutput;
+            if (SLANG_SUCCEEDED(compiler->disassembleWithResult(
+                    spirvCode,
+                    int(spirvWordCount),
+                    disassemblyOutput)))
+            {
+                // Dump the captured disassembly
+                dump(context, "\n");
+                dumpIndent(context);
+                dump(context, disassemblyOutput);
+            }
+            else
+            {
+                dump(context, "<disassembly failed>");
+            }
+        }
+        else
+        {
+            dump(context, "<unavailable disassembler>");
+        }
+    }
+    else
+    {
+        // TODO: Add DXIL disassembly call here.
+        dump(context, "<binary blob>");
+    }
+    dump(context, ")");
+}
+
 static void dumpInstExpr(IRDumpContext* context, IRInst* inst)
 {
     if (!inst)
@@ -7166,6 +7236,13 @@ static void dumpInstExpr(IRDumpContext* context, IRInst* inst)
         }
     }
 
+    // Special case EmbeddedDownstreamIR to show SPIR-V disassembly
+    if (op == kIROp_EmbeddedDownstreamIR)
+    {
+        dumpEmbeddedDownstream(context, inst);
+        return;
+    }
+
     // Special case the SPIR-V asm operands as the distinction here is
     // clear anyway to the user
     switch (op)