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 attached |
31 | /// to the instruction, which 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 attached |
43 | /// to the instruction, which 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 emitting 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 attached |
67 | /// to the instruction, which 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 ExistingWeights A vector of profile weights for each target block |
74 | /// \param IsFrontend 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 | |