1 //===--- MisExpect.h - Check the use of llvm.expect with PGO data ---------===// 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 contains code to emit diagnostic messages for potentially incorrect 10 // usage of the llvm.expect intrinsic. This utility extracts the threshold 11 // values from metadata associated with the instrumented Branch or Switch 12 // instruction. The threshold values are then used to determine if a diagnostic 13 // should be emitted. 14 // 15 //===----------------------------------------------------------------------===// 16 17 #ifndef LLVM_TRANSFORMS_UTILS_MISEXPECT_H 18 #define LLVM_TRANSFORMS_UTILS_MISEXPECT_H 19 20 #include "llvm/ADT/SmallVector.h" 21 #include "llvm/IR/Function.h" 22 #include "llvm/IR/Instructions.h" 23 #include "llvm/IR/LLVMContext.h" 24 25 namespace llvm { 26 namespace misexpect { 27 28 /// checkBackendInstrumentation - compares PGO counters to the thresholds used 29 /// for llvm.expect and warns if the PGO counters are outside of the expected 30 /// range. It extracts the expected weights from the MD_prof weights attatched 31 /// to the instruction, which are are assumed to come from lowered llvm.expect 32 /// intrinsics. The RealWeights parameter and the extracted expected weights are 33 /// then passed to verifyMisexpect() for verification 34 /// 35 /// \param I The Instruction being checked 36 /// \param RealWeights A vector of profile weights for each target block 37 void checkBackendInstrumentation(Instruction &I, 38 const llvm::ArrayRef<uint32_t> RealWeights); 39 40 /// checkFrontendInstrumentation - compares PGO counters to the thresholds used 41 /// for llvm.expect and warns if the PGO counters are outside of the expected 42 /// range. It extracts the expected weights from the MD_prof weights attatched 43 /// to the instruction, which are are assumed to come from profiling data 44 /// attached by the frontend prior to llvm.expect intrinsic lowering. The 45 /// ExpectedWeights parameter and the extracted real weights are then passed to 46 /// verifyMisexpect() for verification 47 /// 48 /// \param I The Instruction being checked 49 /// \param ExpectedWeights A vector of the expected weights for each target 50 /// block, this determines the threshold values used when emiting diagnostics 51 void checkFrontendInstrumentation(Instruction &I, 52 const ArrayRef<uint32_t> ExpectedWeights); 53 54 /// veryifyMisExpect - compares RealWeights to the thresholds used 55 /// for llvm.expect and warns if the PGO counters are outside of the expected 56 /// range. 57 /// 58 /// \param I The Instruction being checked 59 /// \param RealWeights A vector of profile weights from the profile data 60 /// \param ExpectedWeights A vector of the weights attatch by llvm.expect 61 void verifyMisExpect(Instruction &I, ArrayRef<uint32_t> RealWeights, 62 const ArrayRef<uint32_t> ExpectedWeights); 63 64 /// checkExpectAnnotations - compares PGO counters to the thresholds used 65 /// for llvm.expect and warns if the PGO counters are outside of the expected 66 /// range. It extracts the expected weights from the MD_prof weights attatched 67 /// to the instruction, which are are assumed to come from lowered llvm.expect 68 /// intrinsics. The RealWeights parameter and the extracted expected weights are 69 /// then passed to verifyMisexpect() for verification. It is a thin wrapper 70 /// around the checkFrontendInstrumentation and checkBackendInstrumentation APIs 71 /// 72 /// \param I The Instruction being checked 73 /// \param RealWeights A vector of profile weights for each target block 74 /// \param IsBackend A boolean describing if this is Frontend instrumentation 75 void checkExpectAnnotations(Instruction &I, 76 const ArrayRef<uint32_t> ExistingWeights, 77 bool IsFrontend); 78 79 } // namespace misexpect 80 } // namespace llvm 81 82 #endif 83