include/llvm/Transforms/IPO/Inliner.h

   1 //===- Inliner.h - Inliner pass and infrastructure --------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_TRANSFORMS_IPO_INLINER_H
  10 #define LLVM_TRANSFORMS_IPO_INLINER_H
  11
  12 #include "llvm/Analysis/CGSCCPassManager.h"
  13 #include "llvm/Analysis/CallGraphSCCPass.h"
  14 #include "llvm/Analysis/InlineCost.h"
  15 #include "llvm/Analysis/LazyCallGraph.h"
  16 #include "llvm/IR/CallSite.h"
  17 #include "llvm/IR/PassManager.h"
  18 #include "llvm/Transforms/Utils/ImportedFunctionsInliningStatistics.h"
  19 #include <utility>
  20
  21 namespace llvm {
  22
  23 class AssumptionCacheTracker;
  24 class CallGraph;
  25 class ProfileSummaryInfo;
  26
  27 /// This class contains all of the helper code which is used to perform the
  28 /// inlining operations that do not depend on the policy. It contains the core
  29 /// bottom-up inlining infrastructure that specific inliner passes use.
  30 struct LegacyInlinerBase : public CallGraphSCCPass {
  31   explicit LegacyInlinerBase(char &ID);
  32   explicit LegacyInlinerBase(char &ID, bool InsertLifetime);
  33
  34   /// For this class, we declare that we require and preserve the call graph.
  35   /// If the derived class implements this method, it should always explicitly
  36   /// call the implementation here.
  37   void getAnalysisUsage(AnalysisUsage &Info) const override;
  38
  39   bool doInitialization(CallGraph &CG) override;
  40
  41   /// Main run interface method, this implements the interface required by the
  42   /// Pass class.
  43   bool runOnSCC(CallGraphSCC &SCC) override;
  44
  45   using llvm::Pass::doFinalization;
  46
  47   /// Remove now-dead linkonce functions at the end of processing to avoid
  48   /// breaking the SCC traversal.
  49   bool doFinalization(CallGraph &CG) override;
  50
  51   /// This method must be implemented by the subclass to determine the cost of
  52   /// inlining the specified call site.  If the cost returned is greater than
  53   /// the current inline threshold, the call site is not inlined.
  54   virtual InlineCost getInlineCost(CallSite CS) = 0;
  55
  56   /// Remove dead functions.
  57   ///
  58   /// This also includes a hack in the form of the 'AlwaysInlineOnly' flag
  59   /// which restricts it to deleting functions with an 'AlwaysInline'
  60   /// attribute. This is useful for the InlineAlways pass that only wants to
  61   /// deal with that subset of the functions.
  62   bool removeDeadFunctions(CallGraph &CG, bool AlwaysInlineOnly = false);
  63
  64   /// This function performs the main work of the pass.  The default of
  65   /// Inlinter::runOnSCC() calls skipSCC() before calling this method, but
  66   /// derived classes which cannot be skipped can override that method and call
  67   /// this function unconditionally.
  68   bool inlineCalls(CallGraphSCC &SCC);
  69
  70 private:
  71   // Insert @llvm.lifetime intrinsics.
  72   bool InsertLifetime = true;
  73
  74 protected:
  75   AssumptionCacheTracker *ACT;
  76   ProfileSummaryInfo *PSI;
  77   ImportedFunctionsInliningStatistics ImportedFunctionsStats;
  78 };
  79
  80 /// The inliner pass for the new pass manager.
  81 ///
  82 /// This pass wires together the inlining utilities and the inline cost
  83 /// analysis into a CGSCC pass. It considers every call in every function in
  84 /// the SCC and tries to inline if profitable. It can be tuned with a number of
  85 /// parameters to control what cost model is used and what tradeoffs are made
  86 /// when making the decision.
  87 ///
  88 /// It should be noted that the legacy inliners do considerably more than this
  89 /// inliner pass does. They provide logic for manually merging allocas, and
  90 /// doing considerable DCE including the DCE of dead functions. This pass makes
  91 /// every attempt to be simpler. DCE of functions requires complex reasoning
  92 /// about comdat groups, etc. Instead, it is expected that other more focused
  93 /// passes be composed to achieve the same end result.
  94 class InlinerPass : public PassInfoMixin<InlinerPass> {
  95 public:
  96   InlinerPass(InlineParams Params = getInlineParams())
  97       : Params(std::move(Params)) {}
  98   ~InlinerPass();
  99   InlinerPass(InlinerPass &&Arg)
 100       : Params(std::move(Arg.Params)),
 101         ImportedFunctionsStats(std::move(Arg.ImportedFunctionsStats)) {}
 102
 103   PreservedAnalyses run(LazyCallGraph::SCC &C, CGSCCAnalysisManager &AM,
 104                         LazyCallGraph &CG, CGSCCUpdateResult &UR);
 105
 106 private:
 107   InlineParams Params;
 108   std::unique_ptr<ImportedFunctionsInliningStatistics> ImportedFunctionsStats;
 109 };
 110
 111 } // end namespace llvm
 112
 113 #endif // LLVM_TRANSFORMS_IPO_INLINER_H