LLVM  15.0.0git
Internalize.h
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1 //====- Internalize.h - Internalization API ---------------------*- 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 // This pass loops over all of the functions and variables in the input module.
10 // If the function or variable does not need to be preserved according to the
11 // client supplied callback, it is marked as internal.
12 //
13 // This transformation would not be legal in a regular compilation, but it gets
14 // extra information from the linker about what is safe.
15 //
16 // For example: Internalizing a function with external linkage. Only if we are
17 // told it is only used from within this module, it is safe to do it.
18 //
19 //===----------------------------------------------------------------------===//
20 
21 #ifndef LLVM_TRANSFORMS_IPO_INTERNALIZE_H
22 #define LLVM_TRANSFORMS_IPO_INTERNALIZE_H
23 
24 #include "llvm/ADT/DenseMap.h"
25 #include "llvm/ADT/StringSet.h"
26 #include "llvm/IR/PassManager.h"
27 #include <functional>
28 
29 namespace llvm {
30 class Module;
31 class CallGraph;
32 
33 /// A pass that internalizes all functions and variables other than those that
34 /// must be preserved according to \c MustPreserveGV.
35 class InternalizePass : public PassInfoMixin<InternalizePass> {
36  struct ComdatInfo {
37  // The number of members. A comdat with one member which is not externally
38  // visible can be freely dropped.
39  size_t Size = 0;
40  // Whether the comdat has an externally visible member.
41  bool External = false;
42  };
43 
44  bool IsWasm = false;
45 
46  /// Client supplied callback to control wheter a symbol must be preserved.
47  const std::function<bool(const GlobalValue &)> MustPreserveGV;
48  /// Set of symbols private to the compiler that this pass should not touch.
49  StringSet<> AlwaysPreserved;
50 
51  /// Return false if we're allowed to internalize this GV.
52  bool shouldPreserveGV(const GlobalValue &GV);
53  /// Internalize GV if it is possible to do so, i.e. it is not externally
54  /// visible and is not a member of an externally visible comdat.
55  bool maybeInternalize(GlobalValue &GV,
57  /// If GV is part of a comdat and is externally visible, keep track of its
58  /// comdat so that we don't internalize any of its members.
59  void checkComdat(GlobalValue &GV,
61 
62 public:
64  InternalizePass(std::function<bool(const GlobalValue &)> MustPreserveGV)
65  : MustPreserveGV(std::move(MustPreserveGV)) {}
66 
67  /// Run the internalizer on \p TheModule, returns true if any changes was
68  /// made.
69  ///
70  /// If the CallGraph \p CG is supplied, it will be updated when
71  /// internalizing a function (by removing any edge from the "external node")
72  bool internalizeModule(Module &TheModule, CallGraph *CG = nullptr);
73 
75 };
76 
77 /// Helper function to internalize functions and variables in a Module.
78 inline bool
80  std::function<bool(const GlobalValue &)> MustPreserveGV,
81  CallGraph *CG = nullptr) {
82  return InternalizePass(std::move(MustPreserveGV))
83  .internalizeModule(TheModule, CG);
84 }
85 } // end namespace llvm
86 
87 #endif // LLVM_TRANSFORMS_IPO_INTERNALIZE_H
llvm::PreservedAnalyses
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:152
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:17
llvm::PassInfoMixin
A CRTP mix-in to automatically provide informational APIs needed for passes.
Definition: PassManager.h:371
llvm::InternalizePass::internalizeModule
bool internalizeModule(Module &TheModule, CallGraph *CG=nullptr)
Run the internalizer on TheModule, returns true if any changes was made.
Definition: Internalize.cpp:170
llvm::InternalizePass
A pass that internalizes all functions and variables other than those that must be preserved accordin...
Definition: Internalize.h:35
llvm::CallGraph
The basic data container for the call graph of a Module of IR.
Definition: CallGraph.h:72
DenseMap.h
llvm::InternalizePass::InternalizePass
InternalizePass()
Definition: Internalize.cpp:261
llvm::InternalizePass::InternalizePass
InternalizePass(std::function< bool(const GlobalValue &)> MustPreserveGV)
Definition: Internalize.h:64
llvm::GlobalValue
Definition: GlobalValue.h:44
move
compiles ldr LCPI1_0 ldr ldr mov lsr tst moveq r1 ldr LCPI1_1 and r0 bx lr It would be better to do something like to fold the shift into the conditional move
Definition: README.txt:546
llvm::DenseMap
Definition: DenseMap.h:716
llvm::move
OutputIt move(R &&Range, OutputIt Out)
Provide wrappers to std::move which take ranges instead of having to pass begin/end explicitly.
Definition: STLExtras.h:1663
function
print Print MemDeps of function
Definition: MemDepPrinter.cpp:82
llvm::Module
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:65
llvm::internalizeModule
bool internalizeModule(Module &TheModule, std::function< bool(const GlobalValue &)> MustPreserveGV, CallGraph *CG=nullptr)
Helper function to internalize functions and variables in a Module.
Definition: Internalize.h:79
llvm::StringSet
StringSet - A wrapper for StringMap that provides set-like functionality.
Definition: StringSet.h:23
llvm::InternalizePass::run
PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM)
Definition: Internalize.cpp:263
Module
Machine Check Debug Module
Definition: MachineCheckDebugify.cpp:122
StringSet.h
std
Definition: BitVector.h:851
PassManager.h
llvm::AnalysisManager
A container for analyses that lazily runs them and caches their results.
Definition: InstructionSimplify.h:42