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 // simplifyFunc can be expensive, so cache results. 66 // Note that the same function name can be encountered many times due 67 // different lines and addresses in the same function. 68 pruneCache := map[string]bool{} // Map from function to whether or not to prune 69 pruneFromHere := func(s string) bool { 70 if r, ok := pruneCache[s]; ok { 71 return r 72 } 73 funcName := simplifyFunc(s) 74 if dropRx.MatchString(funcName) { 75 if keepRx == nil || !keepRx.MatchString(funcName) { 76 pruneCache[s] = true 77 return true 78 } 79 } 80 pruneCache[s] = false 81 return false 82 } 83 84 for _, loc := range p.Location { 85 var i int 86 for i = len(loc.Line) - 1; i >= 0; i-- { 87 if fn := loc.Line[i].Function; fn != nil && fn.Name != "" { 88 if pruneFromHere(fn.Name) { 89 break 90 } 91 } 92 } 93 94 if i >= 0 { 95 // Found matching entry to prune. 96 pruneBeneath[loc.ID] = true 97 98 // Remove the matching location. 99 if i == len(loc.Line)-1 { 100 // Matched the top entry: prune the whole location. 101 prune[loc.ID] = true 102 } else { 103 loc.Line = loc.Line[i+1:] 104 } 105 } 106 } 107 108 // Prune locs from each Sample 109 for _, sample := range p.Sample { 110 // Scan from the root to the leaves to find the prune location. 111 // Do not prune frames before the first user frame, to avoid 112 // pruning everything. 113 foundUser := false 114 for i := len(sample.Location) - 1; i >= 0; i-- { 115 id := sample.Location[i].ID 116 if !prune[id] && !pruneBeneath[id] { 117 foundUser = true 118 continue 119 } 120 if !foundUser { 121 continue 122 } 123 if prune[id] { 124 sample.Location = sample.Location[i+1:] 125 break 126 } 127 if pruneBeneath[id] { 128 sample.Location = sample.Location[i:] 129 break 130 } 131 } 132 } 133} 134 135// RemoveUninteresting prunes and elides profiles using built-in 136// tables of uninteresting function names. 137func (p *Profile) RemoveUninteresting() error { 138 var keep, drop *regexp.Regexp 139 var err error 140 141 if p.DropFrames != "" { 142 if drop, err = regexp.Compile("^(" + p.DropFrames + ")$"); err != nil { 143 return fmt.Errorf("failed to compile regexp %s: %v", p.DropFrames, err) 144 } 145 if p.KeepFrames != "" { 146 if keep, err = regexp.Compile("^(" + p.KeepFrames + ")$"); err != nil { 147 return fmt.Errorf("failed to compile regexp %s: %v", p.KeepFrames, err) 148 } 149 } 150 p.Prune(drop, keep) 151 } 152 return nil 153} 154 155// PruneFrom removes all nodes beneath the lowest node matching dropRx, not including itself. 156// 157// Please see the example below to understand this method as well as 158// the difference from Prune method. 159// 160// A sample contains Location of [A,B,C,B,D] where D is the top frame and there's no inline. 161// 162// PruneFrom(A) returns [A,B,C,B,D] because there's no node beneath A. 163// Prune(A, nil) returns [B,C,B,D] by removing A itself. 164// 165// PruneFrom(B) returns [B,C,B,D] by removing all nodes beneath the first B when scanning from the bottom. 166// Prune(B, nil) returns [D] because a matching node is found by scanning from the root. 167func (p *Profile) PruneFrom(dropRx *regexp.Regexp) { 168 pruneBeneath := make(map[uint64]bool) 169 170 for _, loc := range p.Location { 171 for i := 0; i < len(loc.Line); i++ { 172 if fn := loc.Line[i].Function; fn != nil && fn.Name != "" { 173 funcName := simplifyFunc(fn.Name) 174 if dropRx.MatchString(funcName) { 175 // Found matching entry to prune. 176 pruneBeneath[loc.ID] = true 177 loc.Line = loc.Line[i:] 178 break 179 } 180 } 181 } 182 } 183 184 // Prune locs from each Sample 185 for _, sample := range p.Sample { 186 // Scan from the bottom leaf to the root to find the prune location. 187 for i, loc := range sample.Location { 188 if pruneBeneath[loc.ID] { 189 sample.Location = sample.Location[i:] 190 break 191 } 192 } 193 } 194} 195