1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "gn/ninja_action_target_writer.h"
6
7 #include <stddef.h>
8
9 #include "base/strings/string_util.h"
10 #include "gn/deps_iterator.h"
11 #include "gn/err.h"
12 #include "gn/general_tool.h"
13 #include "gn/pool.h"
14 #include "gn/settings.h"
15 #include "gn/string_utils.h"
16 #include "gn/substitution_writer.h"
17 #include "gn/target.h"
18
NinjaActionTargetWriter(const Target * target,std::ostream & out)19 NinjaActionTargetWriter::NinjaActionTargetWriter(const Target* target,
20 std::ostream& out)
21 : NinjaTargetWriter(target, out),
22 path_output_no_escaping_(
23 target->settings()->build_settings()->build_dir(),
24 target->settings()->build_settings()->root_path_utf8(),
25 ESCAPE_NONE) {}
26
27 NinjaActionTargetWriter::~NinjaActionTargetWriter() = default;
28
Run()29 void NinjaActionTargetWriter::Run() {
30 std::string custom_rule_name = WriteRuleDefinition();
31
32 // Collect our deps to pass as additional "hard dependencies" for input deps.
33 // This will force all of the action's dependencies to be completed before
34 // the action is run. Usually, if an action has a dependency, it will be
35 // operating on the result of that previous step, so we need to be sure to
36 // serialize these.
37 std::vector<const Target*> additional_hard_deps;
38 std::vector<OutputFile> order_only_deps;
39 const auto& target_deps = resolved().GetTargetDeps(target_);
40
41 for (const Target* dep : target_deps.linked_deps()) {
42 if (dep->IsDataOnly()) {
43 order_only_deps.push_back(dep->dependency_output_file());
44 } else {
45 additional_hard_deps.push_back(dep);
46 }
47 }
48
49 // Add all data-deps to the order-only-deps for the action. The data_deps
50 // field is used to implement different use-cases, including:
51 //
52 // - Files needed at only runtime by the outputs of the action, and therefore
53 // need be built if ninja is building the action's outputs. But they do
54 // not "dirty" the action's outputs if the data_deps alone are "dirty".
55 // If ninja had the concept of "weak" dependencies, that would be used
56 // instead, but that isn't available, so order-only dependencies are used.
57 //
58 // - Files that _may_ need to be used to perform the action, and a depfile
59 // will be used to promote these order-only deps to implicit dependencies,
60 // and on an incremental build, if the now-implicit dependencies are
61 // 'dirty', this action will be considered 'dirty' as well.
62 //
63 for (const Target* data_dep : target_deps.data_deps())
64 order_only_deps.push_back(data_dep->dependency_output_file());
65
66 // For ACTIONs, the input deps appear only once in the generated ninja
67 // file, so WriteInputDepsStampAndGetDep() won't create a stamp file
68 // and the action will just depend on all the input deps directly.
69 size_t num_stamp_uses =
70 target_->output_type() == Target::ACTION ? 1u : target_->sources().size();
71 std::vector<OutputFile> input_deps =
72 WriteInputDepsStampAndGetDep(additional_hard_deps, num_stamp_uses);
73 out_ << std::endl;
74
75 // Collects all output files for writing below.
76 std::vector<OutputFile> output_files;
77
78 if (target_->output_type() == Target::ACTION_FOREACH) {
79 // Write separate build lines for each input source file.
80 WriteSourceRules(custom_rule_name, input_deps, order_only_deps,
81 &output_files);
82 } else {
83 DCHECK(target_->output_type() == Target::ACTION);
84
85 // Write a rule that invokes the script once with the outputs as outputs,
86 // and the data as inputs. It does not depend on the sources.
87 out_ << "build";
88 SubstitutionWriter::GetListAsOutputFiles(
89 settings_, target_->action_values().outputs(), &output_files);
90 WriteOutputs(output_files);
91
92 out_ << ": " << custom_rule_name;
93 if (!input_deps.empty()) {
94 // As in WriteSourceRules, we want to force this target to rebuild any
95 // time any of its dependencies change.
96 out_ << " |";
97 path_output_.WriteFiles(out_, input_deps);
98 }
99 if (!order_only_deps.empty()) {
100 // Write any order-only deps out for actions just like they are for
101 // binaries.
102 out_ << " ||";
103 path_output_.WriteFiles(out_, order_only_deps);
104 }
105
106 out_ << std::endl;
107 if (target_->action_values().has_depfile()) {
108 WriteDepfile(SourceFile());
109 }
110
111 WriteNinjaVariablesForAction();
112
113 if (target_->pool().ptr) {
114 out_ << " pool = ";
115 out_ << target_->pool().ptr->GetNinjaName(
116 settings_->default_toolchain_label());
117 out_ << std::endl;
118 }
119 }
120 out_ << std::endl;
121
122 // Write the stamp, which doesn't need to depend on the data deps because they
123 // have been added as order-only deps of the action output itself.
124 //
125 // TODO(thakis): If the action has just a single output, make things depend
126 // on that output directly without writing a stamp file.
127 std::vector<OutputFile> stamp_file_order_only_deps;
128 WriteStampForTarget(output_files, stamp_file_order_only_deps);
129 }
130
WriteRuleDefinition()131 std::string NinjaActionTargetWriter::WriteRuleDefinition() {
132 // Make a unique name for this rule.
133 //
134 // Use a unique name for the response file when there are multiple build
135 // steps so that they don't stomp on each other. When there are no sources,
136 // there will be only one invocation so we can use a simple name.
137 std::string target_label = target_->label().GetUserVisibleName(true);
138 std::string custom_rule_name(target_label);
139 base::ReplaceChars(custom_rule_name, ":/()+", "_", &custom_rule_name);
140 custom_rule_name.append("_rule");
141
142 const SubstitutionList& args = target_->action_values().args();
143 EscapeOptions args_escape_options;
144 args_escape_options.mode = ESCAPE_NINJA_COMMAND;
145
146 out_ << "rule " << custom_rule_name << std::endl;
147
148 if (target_->action_values().uses_rsp_file()) {
149 // Needs a response file. The unique_name part is for action_foreach so
150 // each invocation of the rule gets a different response file. This isn't
151 // strictly necessary for regular one-shot actions, but it's easier to
152 // just always define unique_name.
153 std::string rspfile = custom_rule_name;
154 if (!target_->sources().empty())
155 rspfile += ".$unique_name";
156 rspfile += ".rsp";
157 out_ << " rspfile = " << rspfile << std::endl;
158
159 // Response file contents.
160 out_ << " rspfile_content =";
161 for (const auto& arg :
162 target_->action_values().rsp_file_contents().list()) {
163 out_ << " ";
164 SubstitutionWriter::WriteWithNinjaVariables(arg, args_escape_options,
165 out_);
166 }
167 out_ << std::endl;
168 }
169
170 // The command line requires shell escaping to properly handle filenames
171 // with spaces.
172 PathOutput command_output(path_output_.current_dir(),
173 settings_->build_settings()->root_path_utf8(),
174 ESCAPE_NINJA_COMMAND);
175
176 out_ << " command = ";
177 command_output.WriteFile(out_, settings_->build_settings()->python_path());
178 out_ << " ";
179 command_output.WriteFile(out_, target_->action_values().script());
180 for (const auto& arg : args.list()) {
181 out_ << " ";
182 SubstitutionWriter::WriteWithNinjaVariables(arg, args_escape_options, out_);
183 }
184 out_ << std::endl;
185 auto mnemonic = target_->action_values().mnemonic();
186 if (mnemonic.empty())
187 mnemonic = "ACTION";
188 out_ << " description = " << mnemonic << " " << target_label << std::endl;
189 out_ << " restat = 1" << std::endl;
190 const Tool* tool =
191 target_->toolchain()->GetTool(GeneralTool::kGeneralToolAction);
192 if (tool && tool->pool().ptr) {
193 out_ << " pool = ";
194 out_ << tool->pool().ptr->GetNinjaName(
195 settings_->default_toolchain_label());
196 out_ << std::endl;
197 }
198
199 return custom_rule_name;
200 }
201
WriteSourceRules(const std::string & custom_rule_name,const std::vector<OutputFile> & input_deps,const std::vector<OutputFile> & order_only_deps,std::vector<OutputFile> * output_files)202 void NinjaActionTargetWriter::WriteSourceRules(
203 const std::string& custom_rule_name,
204 const std::vector<OutputFile>& input_deps,
205 const std::vector<OutputFile>& order_only_deps,
206 std::vector<OutputFile>* output_files) {
207 EscapeOptions args_escape_options;
208 args_escape_options.mode = ESCAPE_NINJA_COMMAND;
209 // We're writing the substitution values, these should not be quoted since
210 // they will get pasted into the real command line.
211 args_escape_options.inhibit_quoting = true;
212
213 const Target::FileList& sources = target_->sources();
214 for (size_t i = 0; i < sources.size(); i++) {
215 out_ << "build";
216 WriteOutputFilesForBuildLine(sources[i], output_files);
217
218 out_ << ": " << custom_rule_name << " ";
219 path_output_.WriteFile(out_, sources[i]);
220 if (!input_deps.empty()) {
221 // Using "|" for the dependencies forces all implicit dependencies to be
222 // fully up to date before running the action, and will re-run this
223 // action if any input dependencies change. This is important because
224 // this action may consume the outputs of previous steps.
225 out_ << " |";
226 path_output_.WriteFiles(out_, input_deps);
227 }
228 if (!order_only_deps.empty()) {
229 // Write any order-only deps out for actions just like they are written
230 // out for binaries.
231 out_ << " ||";
232 path_output_.WriteFiles(out_, order_only_deps);
233 }
234 out_ << std::endl;
235
236 // Response files require a unique name be defined.
237 if (target_->action_values().uses_rsp_file())
238 out_ << " unique_name = " << i << std::endl;
239
240 // The required types is the union of the args and response file. This
241 // might theoretically duplicate a definition if the same substitution is
242 // used in both the args and the response file. However, this should be
243 // very unusual (normally the substitutions will go in one place or the
244 // other) and the redundant assignment won't bother Ninja.
245 SubstitutionWriter::WriteNinjaVariablesForSource(
246 target_, settings_, sources[i],
247 target_->action_values().args().required_types(), args_escape_options,
248 out_);
249 SubstitutionWriter::WriteNinjaVariablesForSource(
250 target_, settings_, sources[i],
251 target_->action_values().rsp_file_contents().required_types(),
252 args_escape_options, out_);
253 WriteNinjaVariablesForAction();
254
255 if (target_->action_values().has_depfile()) {
256 WriteDepfile(sources[i]);
257 }
258 if (target_->pool().ptr) {
259 out_ << " pool = ";
260 out_ << target_->pool().ptr->GetNinjaName(
261 settings_->default_toolchain_label());
262 out_ << std::endl;
263 }
264 }
265 }
266
WriteOutputFilesForBuildLine(const SourceFile & source,std::vector<OutputFile> * output_files)267 void NinjaActionTargetWriter::WriteOutputFilesForBuildLine(
268 const SourceFile& source,
269 std::vector<OutputFile>* output_files) {
270 size_t first_output_index = output_files->size();
271
272 SubstitutionWriter::ApplyListToSourceAsOutputFile(
273 target_, settings_, target_->action_values().outputs(), source,
274 output_files);
275
276 for (size_t i = first_output_index; i < output_files->size(); i++) {
277 out_ << " ";
278 WriteOutput((*output_files)[i]);
279 }
280 }
281
WriteDepfile(const SourceFile & source)282 void NinjaActionTargetWriter::WriteDepfile(const SourceFile& source) {
283 out_ << " depfile = ";
284 path_output_.WriteFile(
285 out_,
286 SubstitutionWriter::ApplyPatternToSourceAsOutputFile(
287 target_, settings_, target_->action_values().depfile(), source));
288 out_ << std::endl;
289 // Using "deps = gcc" allows Ninja to read and store the depfile content in
290 // its internal database which improves performance, especially for large
291 // depfiles. The use of this feature with depfiles that contain multiple
292 // outputs require Ninja version 1.9.0 or newer.
293 if (settings_->build_settings()->ninja_required_version() >=
294 Version{1, 9, 0}) {
295 out_ << " deps = gcc" << std::endl;
296 }
297 }
298
WriteNinjaVariablesForAction()299 void NinjaActionTargetWriter::WriteNinjaVariablesForAction() {
300 SubstitutionBits subst;
301 target_->action_values().args().FillRequiredTypes(&subst);
302 WriteRustCompilerVars(subst, /*indent=*/true, /*always_write=*/false);
303 WriteCCompilerVars(subst, /*indent=*/true, /*respect_source_types=*/false);
304 }
305