LLVM  15.0.0git
CallPromotionUtils.h
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1 //===- CallPromotionUtils.h - Utilities for call promotion ------*- 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 file declares utilities useful for promoting indirect call sites to
10 // direct call sites.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_TRANSFORMS_UTILS_CALLPROMOTIONUTILS_H
15 #define LLVM_TRANSFORMS_UTILS_CALLPROMOTIONUTILS_H
16 
17 namespace llvm {
18 class CallBase;
19 class CastInst;
20 class Function;
21 class MDNode;
22 class Value;
23 
24 /// Return true if the given indirect call site can be made to call \p Callee.
25 ///
26 /// This function ensures that the number and type of the call site's arguments
27 /// and return value match those of the given function. If the types do not
28 /// match exactly, they must at least be bitcast compatible. If \p FailureReason
29 /// is non-null and the indirect call cannot be promoted, the failure reason
30 /// will be stored in it.
31 bool isLegalToPromote(const CallBase &CB, Function *Callee,
32  const char **FailureReason = nullptr);
33 
34 /// Promote the given indirect call site to unconditionally call \p Callee.
35 ///
36 /// This function promotes the given call site, returning the direct call or
37 /// invoke instruction. If the function type of the call site doesn't match that
38 /// of the callee, bitcast instructions are inserted where appropriate. If \p
39 /// RetBitCast is non-null, it will be used to store the return value bitcast,
40 /// if created.
41 CallBase &promoteCall(CallBase &CB, Function *Callee,
42  CastInst **RetBitCast = nullptr);
43 
44 /// Promote the given indirect call site to conditionally call \p Callee.
45 ///
46 /// This function creates an if-then-else structure at the location of the call
47 /// site. The original call site is moved into the "else" block. A clone of the
48 /// indirect call site is promoted, placed in the "then" block, and returned. If
49 /// \p BranchWeights is non-null, it will be used to set !prof metadata on the
50 /// new conditional branch.
51 CallBase &promoteCallWithIfThenElse(CallBase &CB, Function *Callee,
52  MDNode *BranchWeights = nullptr);
53 
54 /// Try to promote (devirtualize) a virtual call on an Alloca. Return true on
55 /// success.
56 ///
57 /// Look for a pattern like:
58 ///
59 /// %o = alloca %class.Impl
60 /// %1 = getelementptr %class.Impl, %class.Impl* %o, i64 0, i32 0, i32 0
61 /// store i32 (...)** bitcast (i8** getelementptr inbounds
62 /// ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV4Impl, i64 0, inrange i32 0, i64 2)
63 /// to i32 (...)**), i32 (...)*** %1
64 /// %2 = getelementptr inbounds %class.Impl, %class.Impl* %o, i64 0, i32 0
65 /// %3 = bitcast %class.Interface* %2 to void (%class.Interface*)***
66 /// %vtable.i = load void (%class.Interface*)**, void (%class.Interface*)*** %3
67 /// %4 = load void (%class.Interface*)*, void (%class.Interface*)** %vtable.i
68 /// call void %4(%class.Interface* nonnull %2)
69 ///
70 /// @_ZTV4Impl = linkonce_odr dso_local unnamed_addr constant { [3 x i8*] }
71 /// { [3 x i8*]
72 /// [i8* null, i8* bitcast ({ i8*, i8*, i8* }* @_ZTI4Impl to i8*),
73 /// i8* bitcast (void (%class.Impl*)* @_ZN4Impl3RunEv to i8*)] }
74 ///
75 bool tryPromoteCall(CallBase &CB);
76 
77 /// Predicate and clone the given call site.
78 ///
79 /// This function creates an if-then-else structure at the location of the call
80 /// site. The "if" condition compares the call site's called value to the given
81 /// callee. The original call site is moved into the "else" block, and a clone
82 /// of the call site is placed in the "then" block. The cloned instruction is
83 /// returned.
84 CallBase &versionCallSite(CallBase &CB, Value *Callee, MDNode *BranchWeights);
85 
86 } // end namespace llvm
87 
88 #endif // LLVM_TRANSFORMS_UTILS_CALLPROMOTIONUTILS_H
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:17
llvm::promoteCallWithIfThenElse
CallBase & promoteCallWithIfThenElse(CallBase &CB, Function *Callee, MDNode *BranchWeights=nullptr)
Promote the given indirect call site to conditionally call Callee.
Definition: CallPromotionUtils.cpp:537
llvm::isLegalToPromote
bool isLegalToPromote(const CallBase &CB, Function *Callee, const char **FailureReason=nullptr)
Return true if the given indirect call site can be made to call Callee.
Definition: CallPromotionUtils.cpp:382
llvm::versionCallSite
CallBase & versionCallSite(CallBase &CB, Value *Callee, MDNode *BranchWeights)
Predicate and clone the given call site.
Definition: CallPromotionUtils.cpp:282
Callee
amdgpu Simplify well known AMD library false FunctionCallee Callee
Definition: AMDGPULibCalls.cpp:186
llvm::TargetStackID::Value
Value
Definition: TargetFrameLowering.h:27
llvm::promoteCall
CallBase & promoteCall(CallBase &CB, Function *Callee, CastInst **RetBitCast=nullptr)
Promote the given indirect call site to unconditionally call Callee.
Definition: CallPromotionUtils.cpp:456
llvm::tryPromoteCall
bool tryPromoteCall(CallBase &CB)
Try to promote (devirtualize) a virtual call on an Alloca.
Definition: CallPromotionUtils.cpp:549
llvm::codeview::PublicSymFlags::Function
@ Function