Merge with master

README.md

@@ -67,7 +67,8 @@ Reverse-mode AD allows computing the gradient of `f` using *at most* a constant
 1. `f` is a pointer to a function or a method to be differentiated
 2. `ARGS` is either:
   * not provided, then `f` is differentiated w.r.t. its every argument
-  * a string literal with comma-separated names of independent variables (e.g. `"x"` or `"y"` or `"x, y"` or `"y, x"`)
+  * a string literal with comma-separated names/indices of independent variables (e.g. `"x"`, `"y"`, `"x, y"`, `"y, x"`, "0, 1", "0, y", etc.)
+  * a SINGLE number representing the index of the independent variable
 
 Since a vector of derivatives must be returned from a function generated by the reverse mode, its signature is slightly different. The generated function has `void` return type and same input arguments. The function has additional `n` arguments (where `n` refers to the number of arguments whose gradient was requested) of type `T*`, where `T` is the type of the corresponding original variable. Each of these variables stores the derivative of the elements as they appear in the orignal function signature. *The caller is responsible for allocating and zeroing-out the gradient storage*. Example:
 ```cpp

VERSION

@@ -1 +1 @@
-1.7~dev
+1.8~dev

docs/internalDocs/ReleaseNotes.md

@@ -2,7 +2,7 @@ Introduction
 ============
 
 This document contains the release notes for the automatic differentiation
-plugin for clang Clad, release 1.7. Clad is built on top of
+plugin for clang Clad, release 1.8. Clad is built on top of
 [Clang](http://clang.llvm.org) and [LLVM](http://llvm.org>) compiler
 infrastructure. Here we describe the status of Clad in some detail, including
 major improvements from the previous release and new feature work.
@@ -11,7 +11,7 @@ Note that if you are reading this file from a git checkout,
 this document applies to the *next* release, not the current one.
 
 
-What's New in Clad 1.7?
+What's New in Clad 1.8?
 ========================
 
 Some of the major new features and improvements to Clad are listed here. Generic
@@ -54,7 +54,7 @@ Fixed Bugs
 [XXX](https://github.com/vgvassilev/clad/issues/XXX)
 
  <!---Get release bugs. Check for close, fix, resolve
- git log v1.6..master | grep -i "close" | grep '#' | sed -E 's,.*\#([0-9]*).*,\[\1\]\(https://github.com/vgvassilev/clad/issues/\1\),g' | sort
+ git log v1.7..master | grep -i "close" | grep '#' | sed -E 's,.*\#([0-9]*).*,\[\1\]\(https://github.com/vgvassilev/clad/issues/\1\),g' | sort
  --->
 
 Special Kudos
@@ -68,5 +68,5 @@ FirstName LastName (#commits)
 A B (N)
 
 <!---Find contributor list for this release
- git log --pretty=format:"%an"  v1.6...master | sort | uniq -c | sort -rn | sed -E 's,^ *([0-9]+) (.*)$,\2 \(\1\),'
+ git log --pretty=format:"%an"  v1.7...master | sort | uniq -c | sort -rn | sed -E 's,^ *([0-9]+) (.*)$,\2 \(\1\),'
 --->

include/clad/Differentiator/BaseForwardModeVisitor.h

@@ -102,6 +102,8 @@ class BaseForwardModeVisitor
   StmtDiff VisitCXXThisExpr(const clang::CXXThisExpr* CTE);
   StmtDiff VisitCXXNewExpr(const clang::CXXNewExpr* CNE);
   StmtDiff VisitCXXDeleteExpr(const clang::CXXDeleteExpr* CDE);
+  StmtDiff
+  VisitCXXScalarValueInitExpr(const clang::CXXScalarValueInitExpr* SVIE);
   StmtDiff VisitCXXStaticCastExpr(const clang::CXXStaticCastExpr* CSE);
   StmtDiff VisitCXXFunctionalCastExpr(const clang::CXXFunctionalCastExpr* FCE);
   StmtDiff VisitCXXBindTemporaryExpr(const clang::CXXBindTemporaryExpr* BTE);

include/clad/Differentiator/DynamicGraph.h

@@ -106,7 +106,7 @@ template <typename T> class DynamicGraph {
   bool isProcessingNode() { return m_currentId != -1; }
 
   /// Get the nodes in the graph.
-  std::vector<T> getNodes() { return m_nodes; }
+  const std::vector<T>& getNodes() { return m_nodes; }
 
   /// Print the nodes and edges in the graph.
   void print() {
@@ -140,4 +140,4 @@ template <typename T> class DynamicGraph {
 };
 } // end namespace clad
 
-#endif // CLAD_DIFFERENTIATOR_DYNAMICGRAPH_H
+#endif // CLAD_DIFFERENTIATOR_DYNAMICGRAPH_H

include/clad/Differentiator/ReverseModeVisitor.h

@@ -411,7 +411,8 @@ namespace clad {
     StmtDiff VisitSwitchStmt(const clang::SwitchStmt* SS);
     StmtDiff VisitCaseStmt(const clang::CaseStmt* CS);
     StmtDiff VisitDefaultStmt(const clang::DefaultStmt* DS);
-    DeclDiff<clang::VarDecl> DifferentiateVarDecl(const clang::VarDecl* VD);
+    DeclDiff<clang::VarDecl> DifferentiateVarDecl(const clang::VarDecl* VD,
+                                                  bool AddToBlock = true);
     StmtDiff VisitSubstNonTypeTemplateParmExpr(
         const clang::SubstNonTypeTemplateParmExpr* NTTP);
     StmtDiff

include/clad/Differentiator/VisitorBase.h

@@ -394,14 +394,12 @@ namespace clad {
     /// to avoid recomputation.
     static bool UsefulToStore(clang::Expr* E);
     /// A flag for silencing warnings/errors output by diag function.
-    bool silenceDiags = false;
     /// Shorthand to issues a warning or error.
     template <std::size_t N>
     void diag(clang::DiagnosticsEngine::Level level, // Warning or Error
               clang::SourceLocation loc, const char (&format)[N],
               llvm::ArrayRef<llvm::StringRef> args = {}) {
-      if (!silenceDiags)
-        m_Builder.diag(level, loc, format, args);
+      m_Builder.diag(level, loc, format, args);
     }
 
     /// Creates unique identifier of the form "_nameBase<number>" that is
@@ -584,17 +582,14 @@ namespace clad {
     clang::Expr* GetSingleArgCentralDiffCall(
         clang::Expr* targetFuncCall, clang::Expr* targetArg, unsigned targetPos,
         unsigned numArgs, llvm::SmallVectorImpl<clang::Expr*>& args);
+
     /// Emits diagnostic messages on differentiation (or lack thereof) for
     /// call expressions.
     ///
-    /// \param[in] \c funcName The name of the underlying function of the
-    /// call expression.
+    /// \param[in] \c FD - The function declaration.
     /// \param[in] \c srcLoc Any associated source location information.
-    /// \param[in] \c isDerived A flag to determine if differentiation of the
-    /// call expression was successful.
-    void CallExprDiffDiagnostics(llvm::StringRef funcName,
-                                 clang::SourceLocation srcLoc,
-                                 bool isDerived);
+    void CallExprDiffDiagnostics(const clang::FunctionDecl* FD,
+                                 clang::SourceLocation srcLoc);
 
     clang::QualType DetermineCladArrayValueType(clang::QualType T);
 

lib/Differentiator/BaseForwardModeVisitor.cpp

@@ -63,7 +63,6 @@ DerivativeAndOverload
 BaseForwardModeVisitor::Derive(const FunctionDecl* FD,
                                const DiffRequest& request) {
   assert(m_DiffReq == request && "Can't pass two different requests!");
-  silenceDiags = !request.VerboseDiags;
   m_Functor = request.Functor;
   assert(m_DiffReq.Mode == DiffMode::forward);
   assert(!m_DerivativeInFlight &&
@@ -801,8 +800,7 @@ StmtDiff BaseForwardModeVisitor::VisitForStmt(const ForStmt* FS) {
     if ((condBO && (condBO->isLogicalOp() || condBO->isAssignmentOp())) ||
         condUO) {
       condDiff = Visit(cond);
-      if (condDiff.getExpr_dx() &&
-          (!isUnusedResult(condDiff.getExpr_dx()) || condUO))
+      if (condDiff.getExpr_dx() && (!isUnusedResult(condDiff.getExpr_dx())))
         cond = BuildOp(BO_Comma, BuildParens(condDiff.getExpr_dx()),
                        BuildParens(condDiff.getExpr()));
       else
@@ -1335,7 +1333,7 @@ StmtDiff BaseForwardModeVisitor::VisitCallExpr(const CallExpr* CE) {
           GetSingleArgCentralDiffCall(fnCallee, CallArgs[0],
                                       /*targetPos=*/0, /*numArgs=*/1, CallArgs);
     }
-    CallExprDiffDiagnostics(FD->getNameAsString(), CE->getBeginLoc(), callDiff);
+    CallExprDiffDiagnostics(FD, CE->getBeginLoc());
     if (!callDiff) {
       auto zero =
           ConstantFolder::synthesizeLiteral(m_Context.IntTy, m_Context, 0);
@@ -1388,7 +1386,15 @@ StmtDiff BaseForwardModeVisitor::VisitUnaryOperator(const UnaryOperator* UnOp) {
   } else if (opKind == UnaryOperatorKind::UO_AddrOf) {
     return StmtDiff(op, BuildOp(opKind, diff.getExpr_dx()));
   } else if (opKind == UnaryOperatorKind::UO_LNot) {
-    return StmtDiff(op, diff.getExpr_dx());
+    Expr* zero = getZeroInit(UnOp->getType());
+    if (diff.getExpr_dx() && !isUnusedResult(diff.getExpr_dx()))
+      return {BuildOp(BO_Comma, BuildParens(diff.getExpr_dx()), op), zero};
+    return {op, zero};
+  } else if (opKind == UnaryOperatorKind::UO_Not) {
+    // ~x is 2^n - 1 - x for unsigned types and -x - 1 for the signed ones.
+    // Either way, taking a derivative gives us -_d_x.
+    Expr* derivedOp = BuildOp(UO_Minus, diff.getExpr_dx());
+    return {op, derivedOp};
   } else {
     unsupportedOpWarn(UnOp->getEndLoc());
     auto zero =
@@ -1504,7 +1510,8 @@ BaseForwardModeVisitor::VisitBinaryOperator(const BinaryOperator* BinOp) {
     } else
       opDiff = BuildOp(BO_Comma, BuildParens(Ldiff.getExpr()),
                        BuildParens(Rdiff.getExpr_dx()));
-  } else if (BinOp->isLogicalOp()) {
+  } else if (BinOp->isLogicalOp() || BinOp->isBitwiseOp() ||
+             BinOp->isComparisonOp() || opCode == BO_Rem) {
     // For (A && B) return ((dA, A) && (dB, B)) to ensure correct evaluation and
     // correct derivative execution.
     auto buildOneSide = [this](StmtDiff& Xdiff) {
@@ -1521,8 +1528,12 @@ BaseForwardModeVisitor::VisitBinaryOperator(const BinaryOperator* BinOp) {
 
     // Since the both parts are included in the opDiff, there's no point in
     // including it as a Stmt_dx. Moreover, the fact that Stmt_dx is left
-    // nullptr is used for treating expressions like ((A && B) && C) correctly.
-    return StmtDiff(opDiff, nullptr);
+    // zero is used for treating expressions like ((A && B) && C) correctly.
+    return StmtDiff(opDiff, getZeroInit(BinOp->getType()));
+  } else if (BinOp->isShiftOp()) {
+    // Shifting is essentially multiplicating the LHS by 2^RHS (or 2^-RHS).
+    // We should do the same to the derivarive.
+    opDiff = BuildOp(opCode, Ldiff.getExpr_dx(), Rdiff.getExpr());
   } else {
     // FIXME: add support for other binary operators
     unsupportedOpWarn(BinOp->getEndLoc());
@@ -2278,6 +2289,11 @@ StmtDiff BaseForwardModeVisitor::VisitCXXStdInitializerListExpr(
   return Visit(ILE->getSubExpr());
 }
 
+StmtDiff BaseForwardModeVisitor::VisitCXXScalarValueInitExpr(
+    const CXXScalarValueInitExpr* SVIE) {
+  return {Clone(SVIE), Clone(SVIE)};
+}
+
 clang::Expr* BaseForwardModeVisitor::BuildCustomDerivativeConstructorPFCall(
     const clang::CXXConstructExpr* CE,
     llvm::SmallVectorImpl<clang::Expr*>& clonedArgs,

lib/Differentiator/DerivativeBuilder.cpp

@@ -194,15 +194,8 @@ static void registerDerivative(FunctionDecl* derivedFD, Sema& semaRef) {
     }
     if (!NSD) {
       NSD = utils::LookupNSD(m_Sema, namespaceID, namespaceShouldExist);
-      if (!forCustomDerv && !NSD) {
-        diag(DiagnosticsEngine::Warning, noLoc,
-             "Numerical differentiation is diabled using the "
-             "-DCLAD_NO_NUM_DIFF "
-             "flag, this means that every try to numerically differentiate a "
-             "function will fail! Remove the flag to revert to default "
-             "behaviour.");
+      if (!NSD)
         return R;
-      }
     }
     DeclContext* DC = NSD;
 

lib/Differentiator/DiffPlanner.cpp

@@ -374,6 +374,21 @@ namespace clad {
         DiffInputVarInfo dVarInfo;
 
         dVarInfo.source = diffSpec.str();
+        // Check if diffSpec represents an index of an independent variable.
+        if ('0' <= diffSpec[0] && diffSpec[0] <= '9') {
+          unsigned idx = std::stoi(dVarInfo.source);
+          // Fail if the specified index is invalid.
+          if (idx >= FD->getNumParams()) {
+            utils::EmitDiag(
+                semaRef, DiagnosticsEngine::Error, diffArgs->getEndLoc(),
+                "Invalid argument index '%0' of '%1' argument(s)",
+                {std::to_string(idx), std::to_string(FD->getNumParams())});
+            return;
+          }
+          dVarInfo.param = FD->getParamDecl(idx);
+          DVI.push_back(dVarInfo);
+          continue;
+        }
         llvm::StringRef pName = computeParamName(diffSpec);
         auto it = std::find_if(std::begin(candidates), std::end(candidates),
                                [&pName](

lib/Differentiator/ReverseModeForwPassVisitor.cpp

@@ -20,7 +20,6 @@ DerivativeAndOverload
 ReverseModeForwPassVisitor::Derive(const FunctionDecl* FD,
                                    const DiffRequest& request) {
   assert(m_DiffReq == request);
-  silenceDiags = !request.VerboseDiags;
 
   assert(m_DiffReq.Mode == DiffMode::reverse_mode_forward_pass);