[OpenACC][CIR] Add lowering for 'copy' array indexes (#140971)

The array indexes(and sections) are represented by the acc.bounds
operation, which this ensures we fill in properly. The lowerbound is
required, so we always get that.

The upperbound or extent is required. We typically do extent, since that
is the 'length' as specified by ACC, but in cases where we have implicit
length, we use the extent instead.

It isn't clear when 'stride' should be anything besides 1, though by my
reading, since we have full-types in the emitted code, we should never
have it be anything but 1.

This patch enables these for copy on compute and combined constructs,
and makes sure to test everything I could think of for
combinations/permutations.

Author: erichkeane

clang/lib/CIR/CodeGen/CIRGenOpenACCClause.cpp

@@ -121,6 +121,11 @@ class OpenACCClauseCIREmitter final
     return constOp.getResult();
   }
 
+  mlir::Value createConstantInt(SourceLocation loc, unsigned width,
+                                int64_t value) {
+    return createConstantInt(cgf.cgm.getLoc(loc), width, value);
+  }
+
   mlir::acc::DeviceType decodeDeviceType(const IdentifierInfo *ii) {
     // '*' case leaves no identifier-info, just a nullptr.
     if (!ii)
@@ -184,37 +189,89 @@ class OpenACCClauseCIREmitter final
     mlir::Location beginLoc;
     mlir::Value varValue;
     llvm::StringRef name;
+    llvm::SmallVector<mlir::Value> bounds;
   };
 
+  mlir::Value createBound(mlir::Location boundLoc, mlir::Value lowerBound,
+                          mlir::Value upperBound, mlir::Value extent) {
+    // Arrays always have a start-idx of 0.
+    mlir::Value startIdx = createConstantInt(boundLoc, 64, 0);
+    // Stride is always 1 in C/C++.
+    mlir::Value stride = createConstantInt(boundLoc, 64, 1);
+
+    auto bound = builder.create<mlir::acc::DataBoundsOp>(boundLoc, lowerBound,
+                                                         upperBound);
+    bound.getStartIdxMutable().assign(startIdx);
+    if (extent)
+      bound.getExtentMutable().assign(extent);
+    bound.getStrideMutable().assign(stride);
+
+    return bound;
+  }
+
   // A helper function that gets the information from an operand to a data
   // clause, so that it can be used to emit the data operations.
-  inline DataOperandInfo getDataOperandInfo(OpenACCDirectiveKind dk,
-                                            const Expr *e) {
+  DataOperandInfo getDataOperandInfo(OpenACCDirectiveKind dk, const Expr *e) {
     // TODO: OpenACC: Cache was different enough as to need a separate
     // `ActOnCacheVar`, so we are going to need to do some investigations here
     // when it comes to implement this for cache.
     if (dk == OpenACCDirectiveKind::Cache) {
       cgf.cgm.errorNYI(e->getSourceRange(),
                        "OpenACC data operand for 'cache' directive");
-      return {cgf.cgm.getLoc(e->getBeginLoc()), {}, {}};
+      return {cgf.cgm.getLoc(e->getBeginLoc()), {}, {}, {}};
     }
 
     const Expr *curVarExpr = e->IgnoreParenImpCasts();
 
     mlir::Location exprLoc = cgf.cgm.getLoc(curVarExpr->getBeginLoc());
+    llvm::SmallVector<mlir::Value> bounds;
+
+    // Assemble the list of bounds.
+    while (isa<ArraySectionExpr, ArraySubscriptExpr>(curVarExpr)) {
+      mlir::Location boundLoc = cgf.cgm.getLoc(curVarExpr->getBeginLoc());
+      mlir::Value lowerBound;
+      mlir::Value upperBound;
+      mlir::Value extent;
+
+      if (const auto *section = dyn_cast<ArraySectionExpr>(curVarExpr)) {
+        if (const Expr *lb = section->getLowerBound())
+          lowerBound = emitIntExpr(lb);
+        else
+          lowerBound = createConstantInt(boundLoc, 64, 0);
+
+        if (const Expr *len = section->getLength()) {
+          extent = emitIntExpr(len);
+        } else {
+          QualType baseTy = ArraySectionExpr::getBaseOriginalType(
+              section->getBase()->IgnoreParenImpCasts());
+          // We know this is the case as implicit lengths are only allowed for
+          // array types with a constant size, or a dependent size.  AND since
+          // we are codegen we know we're not dependent.
+          auto *arrayTy = cgf.getContext().getAsConstantArrayType(baseTy);
+          // Rather than trying to calculate the extent based on the
+          // lower-bound, we can just emit this as an upper bound.
+          upperBound =
+              createConstantInt(boundLoc, 64, arrayTy->getLimitedSize() - 1);
+        }
 
-    // TODO: OpenACC: Assemble the list of bounds.
-    if (isa<ArraySectionExpr, ArraySubscriptExpr>(curVarExpr)) {
-      cgf.cgm.errorNYI(curVarExpr->getSourceRange(),
-                       "OpenACC data clause array subscript/section");
-      return {exprLoc, {}, {}};
+        curVarExpr = section->getBase()->IgnoreParenImpCasts();
+      } else {
+        const auto *subscript = cast<ArraySubscriptExpr>(curVarExpr);
+
+        lowerBound = emitIntExpr(subscript->getIdx());
+        // Length of an array index is always 1.
+        extent = createConstantInt(boundLoc, 64, 1);
+        curVarExpr = subscript->getBase()->IgnoreParenImpCasts();
+      }
+
+      bounds.push_back(createBound(boundLoc, lowerBound, upperBound, extent));
     }
 
     // TODO: OpenACC: if this is a member expr, emit the VarPtrPtr correctly.
     if (isa<MemberExpr>(curVarExpr)) {
       cgf.cgm.errorNYI(curVarExpr->getSourceRange(),
                        "OpenACC Data clause member expr");
-      return {exprLoc, {}, {}};
+      return {exprLoc, {}, {}, std::move(bounds)};
     }
 
     // Sema has made sure that only 4 types of things can get here, array
@@ -223,14 +280,14 @@ class OpenACCClauseCIREmitter final
     // right.
     const auto *dre = cast<DeclRefExpr>(curVarExpr);
     const auto *vd = cast<VarDecl>(dre->getFoundDecl()->getCanonicalDecl());
-    return {exprLoc, cgf.emitDeclRefLValue(dre).getPointer(), vd->getName()};
+    return {exprLoc, cgf.emitDeclRefLValue(dre).getPointer(), vd->getName(),
+            std::move(bounds)};
   }
 
   template <typename BeforeOpTy, typename AfterOpTy>
   void addDataOperand(const Expr *varOperand, mlir::acc::DataClause dataClause,
                       bool structured, bool implicit) {
     DataOperandInfo opInfo = getDataOperandInfo(dirKind, varOperand);
-    mlir::ValueRange bounds;
 
     // TODO: OpenACC: we should comprehend the 'modifier-list' here for the data
     // operand. At the moment, we don't have a uniform way to assign these
@@ -239,7 +296,7 @@ class OpenACCClauseCIREmitter final
 
     auto beforeOp =
         builder.create<BeforeOpTy>(opInfo.beginLoc, opInfo.varValue, structured,
-                                   implicit, opInfo.name, bounds);
+                                   implicit, opInfo.name, opInfo.bounds);
     operation.getDataClauseOperandsMutable().append(beforeOp.getResult());
 
     AfterOpTy afterOp;
@@ -248,7 +305,7 @@ class OpenACCClauseCIREmitter final
       builder.setInsertionPointAfter(operation);
       afterOp = builder.create<AfterOpTy>(opInfo.beginLoc, beforeOp.getResult(),
                                           opInfo.varValue, structured, implicit,
-                                          opInfo.name, bounds);
+                                          opInfo.name, opInfo.bounds);
     }
 
     // Set the 'rest' of the info for both operations.