[function-attrs] Refactor code to handle shorter code with early exits.

[oota-llvm.git] / lib / Transforms / IPO / InlineAlways.cpp

diff --git a/lib/Transforms/IPO/InlineAlways.cpp b/lib/Transforms/IPO/InlineAlways.cpp
index 4e666fb54563970b1f0ab409f8906c82b3f91b9b..83774fbb5fa24caabe271af6577d852abbf79898 100644 (file)
--- a/lib/Transforms/IPO/InlineAlways.cpp
+++ b/lib/Transforms/IPO/InlineAlways.cpp
@@ -12,66 +12,65 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "inline"
-#include "llvm/CallingConv.h"
-#include "llvm/Instructions.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/Module.h"
-#include "llvm/Type.h"
+#include "llvm/Transforms/IPO.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/CallGraph.h"
 #include "llvm/Analysis/InlineCost.h"
-#include "llvm/Support/CallSite.h"
-#include "llvm/Transforms/IPO.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/CallingConv.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
 #include "llvm/Transforms/IPO/InlinerPass.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/ADT/SmallPtrSet.h"
 
 using namespace llvm;
 
+#define DEBUG_TYPE "inline"
+
 namespace {
 
-  // AlwaysInliner only inlines functions that are mark as "always inline".
-  class AlwaysInliner : public Inliner {
-    InlineCostAnalyzer CA;
-  public:
-    // Use extremely low threshold.
-    AlwaysInliner() : Inliner(ID, -2000000000, /*InsertLifetime*/true) {
-      initializeAlwaysInlinerPass(*PassRegistry::getPassRegistry());
-    }
-    AlwaysInliner(bool InsertLifetime) : Inliner(ID, -2000000000,
-                                                 InsertLifetime) {
-      initializeAlwaysInlinerPass(*PassRegistry::getPassRegistry());
-    }
-    static char ID; // Pass identification, replacement for typeid
-    InlineCost getInlineCost(CallSite CS) {
-      Function *Callee = CS.getCalledFunction();
-      // We assume indirect calls aren't calling an always-inline function.
-      if (!Callee) return InlineCost::getNever();
-
-      // We can't inline calls to external functions.
-      // FIXME: We shouldn't even get here.
-      if (Callee->isDeclaration()) return InlineCost::getNever();
-
-      // Return never for anything not marked as always inline.
-      if (!Callee->hasFnAttr(Attribute::AlwaysInline))
-        return InlineCost::getNever();
-
-      // We still have to check the inline cost in case there are reasons to
-      // not inline which trump the always-inline attribute such as setjmp and
-      // indirectbr.
-      return CA.getInlineCost(CS, getInlineThreshold(CS));
-    }
-    virtual bool doFinalization(CallGraph &CG) {
-      return removeDeadFunctions(CG, /*AlwaysInlineOnly=*/true);
-    }
-    virtual bool doInitialization(CallGraph &CG);
-  };
+/// \brief Inliner pass which only handles "always inline" functions.
+class AlwaysInliner : public Inliner {
+  InlineCostAnalysis *ICA;
+
+public:
+  // Use extremely low threshold.
+  AlwaysInliner() : Inliner(ID, -2000000000, /*InsertLifetime*/ true),
+                    ICA(nullptr) {
+    initializeAlwaysInlinerPass(*PassRegistry::getPassRegistry());
+  }
+
+  AlwaysInliner(bool InsertLifetime)
+      : Inliner(ID, -2000000000, InsertLifetime), ICA(nullptr) {
+    initializeAlwaysInlinerPass(*PassRegistry::getPassRegistry());
+  }
+
+  static char ID; // Pass identification, replacement for typeid
+
+  InlineCost getInlineCost(CallSite CS) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+  bool runOnSCC(CallGraphSCC &SCC) override;
+
+  using llvm::Pass::doFinalization;
+  bool doFinalization(CallGraph &CG) override {
+    return removeDeadFunctions(CG, /*AlwaysInlineOnly=*/ true);
+  }
+};
+
 }
 
 char AlwaysInliner::ID = 0;
 INITIALIZE_PASS_BEGIN(AlwaysInliner, "always-inline",
                 "Inliner for always_inline functions", false, false)
-INITIALIZE_AG_DEPENDENCY(CallGraph)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(InlineCostAnalysis)
+INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
 INITIALIZE_PASS_END(AlwaysInliner, "always-inline",
                 "Inliner for always_inline functions", false, false)
 
@@ -81,9 +80,38 @@ Pass *llvm::createAlwaysInlinerPass(bool InsertLifetime) {
   return new AlwaysInliner(InsertLifetime);
 }
 
-// doInitialization - Initializes the vector of functions that have not
-// been annotated with the "always inline" attribute.
-bool AlwaysInliner::doInitialization(CallGraph &CG) {
-  CA.setTargetData(getAnalysisIfAvailable<TargetData>());
-  return false;
+/// \brief Get the inline cost for the always-inliner.
+///
+/// The always inliner *only* handles functions which are marked with the
+/// attribute to force inlining. As such, it is dramatically simpler and avoids
+/// using the powerful (but expensive) inline cost analysis. Instead it uses
+/// a very simple and boring direct walk of the instructions looking for
+/// impossible-to-inline constructs.
+///
+/// Note, it would be possible to go to some lengths to cache the information
+/// computed here, but as we only expect to do this for relatively few and
+/// small functions which have the explicit attribute to force inlining, it is
+/// likely not worth it in practice.
+InlineCost AlwaysInliner::getInlineCost(CallSite CS) {
+  Function *Callee = CS.getCalledFunction();
+
+  // Only inline direct calls to functions with always-inline attributes
+  // that are viable for inlining. FIXME: We shouldn't even get here for
+  // declarations.
+  if (Callee && !Callee->isDeclaration() &&
+      CS.hasFnAttr(Attribute::AlwaysInline) &&
+      ICA->isInlineViable(*Callee))
+    return InlineCost::getAlways();
+
+  return InlineCost::getNever();
+}
+
+bool AlwaysInliner::runOnSCC(CallGraphSCC &SCC) {
+  ICA = &getAnalysis<InlineCostAnalysis>();
+  return Inliner::runOnSCC(SCC);
+}
+
+void AlwaysInliner::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<InlineCostAnalysis>();
+  Inliner::getAnalysisUsage(AU);
 }