commit f2c83a2daeee9a979448fa1ea005332321ee17c2
parent 940625ef28fc8dbcb1138a5fd67ac4e5407d23f9
Author: Kyle Milz <kyle@0x30.net>
Date: Mon, 5 Dec 2016 18:30:01 -0700
src: add comments and tighten functions
Diffstat:
2 files changed, 58 insertions(+), 18 deletions(-)
diff --git a/src/inst_frontend.cc b/src/inst_frontend.cc
@@ -188,6 +188,10 @@ InstrumentFrontend::save_if_srcfile(char *arg)
m_temp_file_map[arg] = dst_fn;
}
+//
+// Careful guessing if we're linking. Use an absolute path to libcitrun.a to
+// avoid link failures.
+//
void
InstrumentFrontend::if_link_add_runtime(bool object_arg, bool compile_arg)
{
@@ -210,18 +214,22 @@ InstrumentFrontend::if_link_add_runtime(bool object_arg, bool compile_arg)
m_args.push_back(const_cast<char *>(CITRUN_SHARE "/libcitrun.a"));
}
+//
+// Walks the entire command line taking action on important arguments.
+//
void
InstrumentFrontend::process_cmdline()
{
bool object_arg = false;
bool compile_arg = false;
- std::ostringstream cmd_line;
+ //
+ // Walk every argument one by one looking for preprocessor switches,
+ // compile mode flags and source files.
+ //
for (auto &arg : m_args) {
- cmd_line << arg << " ";
-
- if (std::strcmp(arg, "-E") == 0 ||
- std::strcmp(arg, "-MM") == 0) {
+ if (std::strcmp(arg, "-E") == 0 || std::strcmp(arg, "-MM") == 0) {
+ // I don't know the repercussions of doing otherwise.
m_log << "Preprocessor argument found" << std::endl;
exec_compiler();
}
@@ -232,9 +240,15 @@ InstrumentFrontend::process_cmdline()
save_if_srcfile(arg);
}
- m_log << "Command line is '" << cmd_line.str() << "'" << std::endl;
+
+ // If linking is detected append libcitrun.a to the command line.
if_link_add_runtime(object_arg, compile_arg);
+ m_log << "Modified command line is '";
+ for (auto &arg : m_args)
+ m_log << arg << " ";
+ m_log << "'" << std::endl;
+
if (m_source_files.size() != 0)
return;
@@ -242,6 +256,9 @@ InstrumentFrontend::process_cmdline()
exec_compiler();
}
+//
+// Creates and executes InstrumentAction objects for detected source files.
+//
void
InstrumentFrontend::instrument()
{
@@ -250,6 +267,7 @@ InstrumentFrontend::instrument()
// clang++ src1.c src2.c -- clang++ -I. -Isrc -c src1.c src2.c
//
std::vector<const char *> clang_argv;
+
clang_argv.push_back(m_args[0]);
for (auto s : m_source_files)
clang_argv.push_back(s.c_str());
@@ -269,32 +287,42 @@ InstrumentFrontend::instrument()
clang::tooling::ClangTool
Tool(op.getCompilations(), op.getSourcePathList());
+ //
+ // These diagnostics aren't too important because the input code could
+ // be terrible.
+ //
clang::TextDiagnosticBuffer diag_buffer;
Tool.setDiagnosticConsumer(&diag_buffer);
std::unique_ptr<InstrumentActionFactory> f =
llvm::make_unique<InstrumentActionFactory>(m_log, m_is_citruninst, m_source_files);
+ // Run the ClangTool over an InstrumentActionFactory, instrumenting and
+ // writing modified source code in place.
int ret = Tool.run(f.get());
-
m_log << "Rewriting " << (ret ? "failed." : "successful.") << std::endl;
+ // All of the time until now is the overhead citrun-inst adds.
std::chrono::high_resolution_clock::time_point now =
std::chrono::high_resolution_clock::now();
m_log << std::chrono::duration_cast<std::chrono::milliseconds>(now - m_start_time).count()
<< " Milliseconds spent rewriting source." << std::endl;
+ // This is as far as we go in citrun-inst mode.
if (m_is_citruninst)
- // This is as far as we go in citrun-inst mode.
exit(ret);
+
+ // If rewriting failed original source files may be in an
+ // inconsistent state.
if (ret) {
- // Rewriting failed. Original source files may be in an
- // inconsistent state.
restore_original_src();
exec_compiler();
}
}
+//
+// Restore source files from stashed backups and sync timestamps.
+//
void
InstrumentFrontend::restore_original_src()
{
@@ -306,45 +334,55 @@ InstrumentFrontend::restore_original_src()
}
}
+//
+// Execute the compiler by calling execvp(3) on the m_args vector.
+//
void
InstrumentFrontend::exec_compiler()
{
if (m_is_citruninst) {
- m_log << "Running as citrun-inst, not re-exec()'ing" << std::endl;
+ m_log << "Running as citrun-inst, not calling exec()" << std::endl;
exit(0);
}
+ // Null termination explicitly mentioned in execvp(3).
m_args.push_back(NULL);
if (execvp(m_args[0], &m_args[0]))
err(1, "execvp");
}
+//
+// fork(2) then execute the compiler and wait for it to finish. Returns exit
+// code of native compiler.
+//
int
InstrumentFrontend::fork_compiler()
{
pid_t child_pid;
+ int status;
+ int exit = -1;
if ((child_pid = fork()) < 0)
err(1, "fork");
+ // If in child execute compiler.
if (child_pid == 0)
- // In child.
exec_compiler();
m_log << "Forked compiler '" << m_args[0] << "' "
<< "pid is '" << child_pid << "'" << std::endl;
- int status;
+ // Wait for the child to finish so we can get its exit code.
if (waitpid(child_pid, &status, 0) < 0)
err(1, "waitpid");
- // Return the exit code of the native compiler.
- int exit = -1;
+ // Decode the exit code from status.
if (WIFEXITED(status))
exit = WEXITSTATUS(status);
- m_log << "Rewritten source compile "
- << (exit ? "failed" : "successful") << std::endl;
+ m_log << "Rewritten source compile " << (exit ? "failed" : "successful")
+ << std::endl;
+ // Return the exit code of the native compiler.
return exit;
}
diff --git a/src/inst_main.cc b/src/inst_main.cc
@@ -19,12 +19,14 @@
int
main(int argc, char *argv[])
{
+ int ret;
+
InstrumentFrontend main(argc, argv);
main.process_cmdline();
main.instrument();
- int ret = main.fork_compiler();
+ ret = main.fork_compiler();
main.restore_original_src();
if (ret)
