1// Copyright 2014 Google Inc. All Rights Reserved. 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15// Implements methods to remove frames from profiles. 16 17package profile 18 19import ( 20 "fmt" 21 "regexp" 22 "strings" 23) 24 25var ( 26 reservedNames = []string{"(anonymous namespace)", "operator()"} 27 bracketRx = func() *regexp.Regexp { 28 var quotedNames []string 29 for _, name := range append(reservedNames, "(") { 30 quotedNames = append(quotedNames, regexp.QuoteMeta(name)) 31 } 32 return regexp.MustCompile(strings.Join(quotedNames, "|")) 33 }() 34) 35 36// simplifyFunc does some primitive simplification of function names. 37func simplifyFunc(f string) string { 38 // Account for leading '.' on the PPC ELF v1 ABI. 39 funcName := strings.TrimPrefix(f, ".") 40 // Account for unsimplified names -- try to remove the argument list by trimming 41 // starting from the first '(', but skipping reserved names that have '('. 42 for _, ind := range bracketRx.FindAllStringSubmatchIndex(funcName, -1) { 43 foundReserved := false 44 for _, res := range reservedNames { 45 if funcName[ind[0]:ind[1]] == res { 46 foundReserved = true 47 break 48 } 49 } 50 if !foundReserved { 51 funcName = funcName[:ind[0]] 52 break 53 } 54 } 55 return funcName 56} 57 58// Prune removes all nodes beneath a node matching dropRx, and not 59// matching keepRx. If the root node of a Sample matches, the sample 60// will have an empty stack. 61func (p *Profile) Prune(dropRx, keepRx *regexp.Regexp) { 62 prune := make(map[uint64]bool) 63 pruneBeneath := make(map[uint64]bool) 64 65 for _, loc := range p.Location { 66 var i int 67 for i = len(loc.Line) - 1; i >= 0; i-- { 68 if fn := loc.Line[i].Function; fn != nil && fn.Name != "" { 69 funcName := simplifyFunc(fn.Name) 70 if dropRx.MatchString(funcName) { 71 if keepRx == nil || !keepRx.MatchString(funcName) { 72 break 73 } 74 } 75 } 76 } 77 78 if i >= 0 { 79 // Found matching entry to prune. 80 pruneBeneath[loc.ID] = true 81 82 // Remove the matching location. 83 if i == len(loc.Line)-1 { 84 // Matched the top entry: prune the whole location. 85 prune[loc.ID] = true 86 } else { 87 loc.Line = loc.Line[i+1:] 88 } 89 } 90 } 91 92 // Prune locs from each Sample 93 for _, sample := range p.Sample { 94 // Scan from the root to the leaves to find the prune location. 95 // Do not prune frames before the first user frame, to avoid 96 // pruning everything. 97 foundUser := false 98 for i := len(sample.Location) - 1; i >= 0; i-- { 99 id := sample.Location[i].ID 100 if !prune[id] && !pruneBeneath[id] { 101 foundUser = true 102 continue 103 } 104 if !foundUser { 105 continue 106 } 107 if prune[id] { 108 sample.Location = sample.Location[i+1:] 109 break 110 } 111 if pruneBeneath[id] { 112 sample.Location = sample.Location[i:] 113 break 114 } 115 } 116 } 117} 118 119// RemoveUninteresting prunes and elides profiles using built-in 120// tables of uninteresting function names. 121func (p *Profile) RemoveUninteresting() error { 122 var keep, drop *regexp.Regexp 123 var err error 124 125 if p.DropFrames != "" { 126 if drop, err = regexp.Compile("^(" + p.DropFrames + ")$"); err != nil { 127 return fmt.Errorf("failed to compile regexp %s: %v", p.DropFrames, err) 128 } 129 if p.KeepFrames != "" { 130 if keep, err = regexp.Compile("^(" + p.KeepFrames + ")$"); err != nil { 131 return fmt.Errorf("failed to compile regexp %s: %v", p.KeepFrames, err) 132 } 133 } 134 p.Prune(drop, keep) 135 } 136 return nil 137} 138 139// PruneFrom removes all nodes beneath the lowest node matching dropRx, not including itself. 140// 141// Please see the example below to understand this method as well as 142// the difference from Prune method. 143// 144// A sample contains Location of [A,B,C,B,D] where D is the top frame and there's no inline. 145// 146// PruneFrom(A) returns [A,B,C,B,D] because there's no node beneath A. 147// Prune(A, nil) returns [B,C,B,D] by removing A itself. 148// 149// PruneFrom(B) returns [B,C,B,D] by removing all nodes beneath the first B when scanning from the bottom. 150// Prune(B, nil) returns [D] because a matching node is found by scanning from the root. 151func (p *Profile) PruneFrom(dropRx *regexp.Regexp) { 152 pruneBeneath := make(map[uint64]bool) 153 154 for _, loc := range p.Location { 155 for i := 0; i < len(loc.Line); i++ { 156 if fn := loc.Line[i].Function; fn != nil && fn.Name != "" { 157 funcName := simplifyFunc(fn.Name) 158 if dropRx.MatchString(funcName) { 159 // Found matching entry to prune. 160 pruneBeneath[loc.ID] = true 161 loc.Line = loc.Line[i:] 162 break 163 } 164 } 165 } 166 } 167 168 // Prune locs from each Sample 169 for _, sample := range p.Sample { 170 // Scan from the bottom leaf to the root to find the prune location. 171 for i, loc := range sample.Location { 172 if pruneBeneath[loc.ID] { 173 sample.Location = sample.Location[i:] 174 break 175 } 176 } 177 } 178} 179