1 //===- InlinerPass.h - Code common to all inliners --------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines a simple policy-based bottom-up inliner.  This file
11 // implements all of the boring mechanics of the bottom-up inlining, while the
12 // subclass determines WHAT to inline, which is the much more interesting
13 // component.
14 //
15 //===----------------------------------------------------------------------===//
16 
17 #ifndef LLVM_TRANSFORMS_IPO_INLINERPASS_H
18 #define LLVM_TRANSFORMS_IPO_INLINERPASS_H
19 
20 #include "llvm/Analysis/CallGraphSCCPass.h"
21 
22 namespace llvm {
23   class CallSite;
24   class DataLayout;
25   class InlineCost;
26   template<class PtrType, unsigned SmallSize>
27   class SmallPtrSet;
28 
29 /// Inliner - This class contains all of the helper code which is used to
30 /// perform the inlining operations that do not depend on the policy.
31 ///
32 struct Inliner : public CallGraphSCCPass {
33   explicit Inliner(char &ID);
34   explicit Inliner(char &ID, int Threshold, bool InsertLifetime);
35 
36   /// getAnalysisUsage - For this class, we declare that we require and preserve
37   /// the call graph.  If the derived class implements this method, it should
38   /// always explicitly call the implementation here.
39   void getAnalysisUsage(AnalysisUsage &Info) const 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   // doFinalization - Remove now-dead linkonce functions at the end of
47   // processing to avoid breaking the SCC traversal.
48   bool doFinalization(CallGraph &CG) override;
49 
50   /// This method returns the value specified by the -inline-threshold value,
51   /// specified on the command line.  This is typically not directly needed.
52   ///
getInlineThresholdInliner53   unsigned getInlineThreshold() const { return InlineThreshold; }
54 
55   /// Calculate the inline threshold for given Caller. This threshold is lower
56   /// if the caller is marked with OptimizeForSize and -inline-threshold is not
57   /// given on the comand line. It is higher if the callee is marked with the
58   /// inlinehint attribute.
59   ///
60   unsigned getInlineThreshold(CallSite CS) const;
61 
62   /// getInlineCost - This method must be implemented by the subclass to
63   /// determine the cost of inlining the specified call site.  If the cost
64   /// returned is greater than the current inline threshold, the call site is
65   /// not inlined.
66   ///
67   virtual InlineCost getInlineCost(CallSite CS) = 0;
68 
69   /// removeDeadFunctions - Remove dead functions.
70   ///
71   /// This also includes a hack in the form of the 'AlwaysInlineOnly' flag
72   /// which restricts it to deleting functions with an 'AlwaysInline'
73   /// attribute. This is useful for the InlineAlways pass that only wants to
74   /// deal with that subset of the functions.
75   bool removeDeadFunctions(CallGraph &CG, bool AlwaysInlineOnly = false);
76 
77 private:
78   // InlineThreshold - Cache the value here for easy access.
79   unsigned InlineThreshold;
80 
81   // InsertLifetime - Insert @llvm.lifetime intrinsics.
82   bool InsertLifetime;
83 
84   /// shouldInline - Return true if the inliner should attempt to
85   /// inline at the given CallSite.
86   bool shouldInline(CallSite CS);
87 };
88 
89 } // End llvm namespace
90 
91 #endif
92