Rename IslCodeGeneration to CodeGeneration

Besides class, function and file names, we also change the command line option
from -polly-codegen-isl to just -polly-codegen. The isl postfix is a leftover
from the times when we still had the CLooG based -polly-codegen. Today it is
just redundant and we drop it.

llvm-svn: 237099
diff --git a/polly/lib/CodeGen/CodeGeneration.cpp b/polly/lib/CodeGen/CodeGeneration.cpp
new file mode 100644
index 0000000..22aafee
--- /dev/null
+++ b/polly/lib/CodeGen/CodeGeneration.cpp
@@ -0,0 +1,181 @@
+//===------ CodeGeneration.cpp - Code generate the Scops using ISL. ----======//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// The CodeGeneration pass takes a Scop created by ScopInfo and translates it
+// back to LLVM-IR using the ISL code generator.
+//
+// The Scop describes the high level memory behaviour of a control flow region.
+// Transformation passes can update the schedule (execution order) of statements
+// in the Scop. ISL is used to generate an abstract syntax tree that reflects
+// the updated execution order. This clast is used to create new LLVM-IR that is
+// computationally equivalent to the original control flow region, but executes
+// its code in the new execution order defined by the changed schedule.
+//
+//===----------------------------------------------------------------------===//
+
+#include "polly/CodeGen/IslNodeBuilder.h"
+#include "polly/CodeGen/IslAst.h"
+#include "polly/CodeGen/Utils.h"
+#include "polly/DependenceInfo.h"
+#include "polly/LinkAllPasses.h"
+#include "polly/ScopInfo.h"
+#include "polly/Support/ScopHelper.h"
+#include "polly/TempScopInfo.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/Support/Debug.h"
+
+using namespace polly;
+using namespace llvm;
+
+#define DEBUG_TYPE "polly-codegen"
+
+namespace {
+class CodeGeneration : public ScopPass {
+public:
+  static char ID;
+
+  CodeGeneration() : ScopPass(ID) {}
+
+  /// @brief The datalayout used
+  const DataLayout *DL;
+
+  /// @name The analysis passes we need to generate code.
+  ///
+  ///{
+  LoopInfo *LI;
+  IslAstInfo *AI;
+  DominatorTree *DT;
+  ScalarEvolution *SE;
+  ///}
+
+  /// @brief The loop annotator to generate llvm.loop metadata.
+  ScopAnnotator Annotator;
+
+  /// @brief Build the runtime condition.
+  ///
+  /// Build the condition that evaluates at run-time to true iff all
+  /// assumptions taken for the SCoP hold, and to false otherwise.
+  ///
+  /// @return A value evaluating to true/false if execution is save/unsafe.
+  Value *buildRTC(PollyIRBuilder &Builder, IslExprBuilder &ExprBuilder) {
+    Builder.SetInsertPoint(Builder.GetInsertBlock()->getTerminator());
+    Value *RTC = ExprBuilder.create(AI->getRunCondition());
+    if (!RTC->getType()->isIntegerTy(1))
+      RTC = Builder.CreateIsNotNull(RTC);
+    return RTC;
+  }
+
+  bool verifyGeneratedFunction(Scop &S, Function &F) {
+    if (!verifyFunction(F))
+      return false;
+
+    DEBUG({
+      errs() << "== ISL Codegen created an invalid function ==\n\n== The "
+                "SCoP ==\n";
+      S.print(errs());
+      errs() << "\n== The isl AST ==\n";
+      AI->printScop(errs(), S);
+      errs() << "\n== The invalid function ==\n";
+      F.print(errs());
+      errs() << "\n== The errors ==\n";
+      verifyFunction(F, &errs());
+    });
+
+    return true;
+  }
+
+  bool runOnScop(Scop &S) override {
+    AI = &getAnalysis<IslAstInfo>();
+
+    // Check if we created an isl_ast root node, otherwise exit.
+    isl_ast_node *AstRoot = AI->getAst();
+    if (!AstRoot)
+      return false;
+
+    LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+    DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+    SE = &getAnalysis<ScalarEvolution>();
+    DL = &S.getRegion().getEntry()->getParent()->getParent()->getDataLayout();
+
+    assert(!S.getRegion().isTopLevelRegion() &&
+           "Top level regions are not supported");
+
+    Annotator.buildAliasScopes(S);
+
+    BasicBlock *EnteringBB = simplifyRegion(&S, this);
+    PollyIRBuilder Builder = createPollyIRBuilder(EnteringBB, Annotator);
+
+    IslNodeBuilder NodeBuilder(Builder, Annotator, this, *DL, *LI, *SE, *DT, S);
+
+    // Only build the run-time condition and parameters _after_ having
+    // introduced the conditional branch. This is important as the conditional
+    // branch will guard the original scop from new induction variables that
+    // the SCEVExpander may introduce while code generating the parameters and
+    // which may introduce scalar dependences that prevent us from correctly
+    // code generating this scop.
+    BasicBlock *StartBlock =
+        executeScopConditionally(S, this, Builder.getTrue());
+    auto SplitBlock = StartBlock->getSinglePredecessor();
+    Builder.SetInsertPoint(SplitBlock->getTerminator());
+    NodeBuilder.addParameters(S.getContext());
+    Value *RTC = buildRTC(Builder, NodeBuilder.getExprBuilder());
+    SplitBlock->getTerminator()->setOperand(0, RTC);
+    Builder.SetInsertPoint(StartBlock->begin());
+
+    NodeBuilder.create(AstRoot);
+
+    assert(!verifyGeneratedFunction(S, *EnteringBB->getParent()) &&
+           "Verification of generated function failed");
+    return true;
+  }
+
+  void printScop(raw_ostream &, Scop &) const override {}
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<DominatorTreeWrapperPass>();
+    AU.addRequired<IslAstInfo>();
+    AU.addRequired<RegionInfoPass>();
+    AU.addRequired<ScalarEvolution>();
+    AU.addRequired<ScopDetection>();
+    AU.addRequired<ScopInfo>();
+    AU.addRequired<LoopInfoWrapperPass>();
+
+    AU.addPreserved<DependenceInfo>();
+
+    AU.addPreserved<LoopInfoWrapperPass>();
+    AU.addPreserved<DominatorTreeWrapperPass>();
+    AU.addPreserved<IslAstInfo>();
+    AU.addPreserved<ScopDetection>();
+    AU.addPreserved<ScalarEvolution>();
+
+    // FIXME: We do not yet add regions for the newly generated code to the
+    //        region tree.
+    AU.addPreserved<RegionInfoPass>();
+    AU.addPreserved<TempScopInfo>();
+    AU.addPreserved<ScopInfo>();
+    AU.addPreservedID(IndependentBlocksID);
+  }
+};
+}
+
+char CodeGeneration::ID = 1;
+
+Pass *polly::createCodeGenerationPass() { return new CodeGeneration(); }
+
+INITIALIZE_PASS_BEGIN(CodeGeneration, "polly-codegen",
+                      "Polly - Create LLVM-IR from SCoPs", false, false);
+INITIALIZE_PASS_DEPENDENCY(DependenceInfo);
+INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass);
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
+INITIALIZE_PASS_DEPENDENCY(RegionInfoPass);
+INITIALIZE_PASS_DEPENDENCY(ScalarEvolution);
+INITIALIZE_PASS_DEPENDENCY(ScopDetection);
+INITIALIZE_PASS_END(CodeGeneration, "polly-codegen",
+                    "Polly - Create LLVM-IR from SCoPs", false, false)