Add IGlobalSession::getSessionDescDigest. (#3669)

* Add `IGlobalSession::getSessionDescDigest`. * Fix.
shader-slang · Mar 4, 2024 · 01efe34 · 01efe34
1 parent 16342f4
commit 01efe34
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Showing 3 changed files with 58 additions and 24 deletions.
diff --git a/slang.h b/slang.h
@@ -3737,6 +3737,10 @@ namespace slang
             */
         virtual SLANG_NO_THROW SlangResult SLANG_MCALL parseCommandLineArguments(
             int argc, const char* const* argv, SessionDesc* outSessionDesc, ISlangUnknown** outAuxAllocation) = 0;
+
+            /** Computes a digest that uniquely identifies the session description.
+            */
+        virtual SLANG_NO_THROW SlangResult SLANG_MCALL getSessionDescDigest(SessionDesc* sessionDesc, ISlangBlob** outBlob) = 0;
     };
 
     #define SLANG_UUID_IGlobalSession IGlobalSession::getTypeGuid()

diff --git a/source/slang/slang-compiler.h b/source/slang/slang-compiler.h
@@ -1835,7 +1835,7 @@ namespace Slang
         // Updates the supplied builder with linkage-related information, which includes preprocessor
         // defines, the compiler version, and other compiler options. This is then merged with the hash
         // produced for the program to produce a key that can be used with the shader cache.
-        void buildHash(DigestBuilder<SHA1>& builder, SlangInt targetIndex);
+        void buildHash(DigestBuilder<SHA1>& builder, SlangInt targetIndex = -1);
 
         void addTarget(
             slang::TargetDesc const& desc);
@@ -3003,6 +3003,8 @@ namespace Slang
         SLANG_NO_THROW SlangResult SLANG_MCALL parseCommandLineArguments(
             int argc, const char* const* argv, slang::SessionDesc* outSessionDesc, ISlangUnknown** outAllocation) override;
 
+        SLANG_NO_THROW SlangResult SLANG_MCALL getSessionDescDigest(slang::SessionDesc* sessionDesc, ISlangBlob** outBlob) override;
+
             /// Get the downstream compiler for a transition
         IDownstreamCompiler* getDownstreamCompiler(CodeGenTarget source, CodeGenTarget target);
 

diff --git a/source/slang/slang.cpp b/source/slang/slang.cpp
@@ -878,6 +878,18 @@ SLANG_NO_THROW SlangResult SLANG_MCALL Session::parseCommandLineArguments(
     return SLANG_OK;
 }
 
+SLANG_NO_THROW SlangResult SLANG_MCALL Session::getSessionDescDigest(slang::SessionDesc* sessionDesc, ISlangBlob** outBlob)
+{
+    ComPtr<slang::ISession> tempSession;
+    createSession(*sessionDesc, tempSession.writeRef());
+    auto linkage = static_cast<Linkage*>(tempSession.get());
+    DigestBuilder<SHA1> digestBuilder;
+    linkage->buildHash(digestBuilder, -1);
+    auto blob = digestBuilder.finalize().toBlob();
+    *outBlob = blob.detach();
+    return SLANG_OK;
+}
+
 Profile getEffectiveProfile(EntryPoint* entryPoint, TargetRequest* target)
 {
     auto entryPointProfile = entryPoint->getProfile();
@@ -1488,37 +1500,53 @@ void Linkage::buildHash(DigestBuilder<SHA1>& builder, SlangInt targetIndex)
     // Add compiler options, including search path, preprocessor includes, etc.
     m_optionSet.buildHash(builder);
 
-    // Add the target specified by targetIndex
-    auto targetReq = targets[targetIndex];
-    targetReq->getOptionSet().buildHash(builder);
+    auto addTargetDigest = [&](TargetRequest* targetReq)
+    {
+        targetReq->getOptionSet().buildHash(builder);
 
-    const PassThroughMode passThroughMode = getDownstreamCompilerRequiredForTarget(targetReq->getTarget());
-    const SourceLanguage sourceLanguage = getDefaultSourceLanguageForDownstreamCompiler(passThroughMode);
+        const PassThroughMode passThroughMode = getDownstreamCompilerRequiredForTarget(targetReq->getTarget());
+        const SourceLanguage sourceLanguage = getDefaultSourceLanguageForDownstreamCompiler(passThroughMode);
 
-    // Add prelude for the given downstream compiler.
-    ComPtr<ISlangBlob> prelude;
-    getGlobalSession()->getLanguagePrelude((SlangSourceLanguage)sourceLanguage, prelude.writeRef());
-    if (prelude)
-    {
-        builder.append(prelude);
-    }
+        // Add prelude for the given downstream compiler.
+        ComPtr<ISlangBlob> prelude;
+        getGlobalSession()->getLanguagePrelude((SlangSourceLanguage)sourceLanguage, prelude.writeRef());
+        if (prelude)
+        {
+            builder.append(prelude);
+        }
 
-    // TODO: Downstream compilers (specifically dxc) can currently #include additional dependencies.
-    // This is currently the case for NVAPI headers included in the prelude.
-    // These dependencies are currently not picked up by the shader cache which is a significant issue.
-    // This can only be fixed by running the preprocessor in the slang compiler so dxc (or any other
-    // downstream compiler for that matter) isn't resolving any includes implicitly.
+        // TODO: Downstream compilers (specifically dxc) can currently #include additional dependencies.
+        // This is currently the case for NVAPI headers included in the prelude.
+        // These dependencies are currently not picked up by the shader cache which is a significant issue.
+        // This can only be fixed by running the preprocessor in the slang compiler so dxc (or any other
+        // downstream compiler for that matter) isn't resolving any includes implicitly.
 
-    // Add the downstream compiler version (if it exists) to the hash
-    auto downstreamCompiler = getSessionImpl()->getOrLoadDownstreamCompiler(passThroughMode, nullptr);
-    if (downstreamCompiler)
+        // Add the downstream compiler version (if it exists) to the hash
+        auto downstreamCompiler = getSessionImpl()->getOrLoadDownstreamCompiler(passThroughMode, nullptr);
+        if (downstreamCompiler)
+        {
+            ComPtr<ISlangBlob> versionString;
+            if (SLANG_SUCCEEDED(downstreamCompiler->getVersionString(versionString.writeRef())))
+            {
+                builder.append(versionString);
+            }
+        }
+    };
+
+    // Add the target specified by targetIndex
+    if (targetIndex == -1)
     {
-        ComPtr<ISlangBlob> versionString;
-        if (SLANG_SUCCEEDED(downstreamCompiler->getVersionString(versionString.writeRef())))
+        // -1 means all targets.
+        for (auto targetReq : targets)
         {
-            builder.append(versionString);
+            addTargetDigest(targetReq);
         }
     }
+    else
+    {
+        auto targetReq = targets[targetIndex];
+        addTargetDigest(targetReq);
+    }
 }
 
 SlangResult Linkage::addSearchPath(