Add clang-repl tests to make sure we do not break repls.

Fixes vgvassilev#854, fixes vgvassilev#867.

.github/workflows/ci.yml

@@ -682,7 +682,7 @@ jobs:
               -DLLVM_INCLUDE_TESTS=OFF              \
               -DLLVM_INCLUDE_DOCS=OFF               \
               ../llvm
-        cmake --build . --target clang FileCheck llvm-config --parallel ${CPU_COUNT}
+        cmake --build . --target clang FileCheck llvm-config clang-repl --parallel ${CPU_COUNT}
         cd ../../
     - name: Save Cache LLVM/Clang runtime build directory (debug_build==true)
       uses: actions/cache/save@v3

test/Misc/Repl.cpp

@@ -0,0 +1,10 @@
+// REQUIRES: clang-repl
+// UNSUPPORTED: clang-13, clang-14, clang-15, clang-17
+// RUN: cat %s | %clang-repl -Xcc -fplugin=%cladlib -Xcc -I%S/../../include | FileCheck %s
+
+double sq(double x) { return x*x; }
+extern "C" int printf(const char*,...);
+#include "clad/Differentiator/Differentiator.h"
+auto dsq = clad::differentiate(sq, "x");
+auto r1 = printf("dsq(1)=%f\n", dsq.execute(1));
+// CHECK: dsq(1)=2.00

test/lit.cfg

@@ -297,6 +297,20 @@ if platform.system() not in ['Windows'] or lit_config.getBashPath() != '':
 
 config.available_features.add("clang-{0}".format(config.clang_version_major))
 
+# Check if we have clang-repl next to the inferred clang folder.
+inferred_binary_dir = os.path.dirname(config.clang)
+clang_repl_path = ""
+
+if os.path.exists(os.path.join(inferred_binary_dir, "clang-repl-{0}".format(config.clang_version_major))):
+  clang_repl_path = os.path.join(inferred_binary_dir, "clang-repl-{0}".format(config.clang_version_major))
+elif os.path.exists(os.path.join(inferred_binary_dir, 'clang-repl')):
+  clang_repl_path = os.path.join(inferred_binary_dir, 'clang-repl')
+  config.available_features.add("clang-repl-{0}".format(config.clang_version_major))
+
+if clang_repl_path:
+  config.available_features.add("clang-repl")
+  config.substitutions.append(("%clang-repl", clang_repl_path))
+
 # Loadable module
 # FIXME: This should be supplied by Makefile or autoconf.
 #if sys.platform in ['win32', 'cygwin']:

tools/ClangPlugin.cpp

@@ -292,7 +292,9 @@ namespace clad {
     }
 
     void CladPlugin::SendToMultiplexer() {
-      for (auto DelayedCall : m_DelayedCalls) {
+      for (unsigned i = m_MultiplexerProcessedDelayedCallsIdx;
+           i < m_DelayedCalls.size(); ++i) {
+        auto DelayedCall = m_DelayedCalls[i];
         DeclGroupRef& D = DelayedCall.m_DGR;
         switch (DelayedCall.m_Kind) {
         case CallKind::HandleCXXStaticMemberVarInstantiation:
@@ -350,7 +352,8 @@ namespace clad {
           break;
         };
       }
-      m_HasMultiplexerProcessedDelayedCalls = true;
+
+      m_MultiplexerProcessedDelayedCallsIdx = m_DelayedCalls.size();
     }
 
     bool CladPlugin::CheckBuiltins() {

tools/ClangPlugin.h

@@ -16,6 +16,7 @@
 #include "clang/AST/Decl.h"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/Basic/Version.h"
+#include "clang/Frontend/CompilerInstance.h"
 #include "clang/Frontend/FrontendPluginRegistry.h"
 #include "clang/Frontend/MultiplexConsumer.h"
 #include "clang/Sema/SemaConsumer.h"
@@ -27,7 +28,6 @@
 namespace clang {
   class ASTContext;
   class CallExpr;
-  class CompilerInstance;
   class DeclGroupRef;
   class Expr;
   class FunctionDecl;
@@ -153,7 +153,7 @@ class CladTimerGroup {
     std::unique_ptr<clang::MultiplexConsumer> m_Multiplexer;
 
     /// Have we processed all delayed calls.
-    bool m_HasMultiplexerProcessedDelayedCalls = false;
+    unsigned m_MultiplexerProcessedDelayedCallsIdx = 0;
 
     /// The Sema::TUScope to restore in CladPlugin::HandleTranslationUnit.
     clang::Scope* m_StoredTUScope = nullptr;
@@ -247,7 +247,11 @@ class CladTimerGroup {
 
   private:
     void AppendDelayed(DelayedCallInfo DCI) {
-      assert(!m_HasMultiplexerProcessedDelayedCalls);
+      // Incremental processing handles the translation unit in chunks and it is
+      // expected to have multiple calls to this functionality.
+      assert((!m_MultiplexerProcessedDelayedCallsIdx ||
+              m_CI.getPreprocessor().isIncrementalProcessingEnabled()) &&
+             "Must start from index 0!");
       m_DelayedCalls.push_back(DCI);
     }
     void SendToMultiplexer();