teak-llvm/clang/lib/Driver/Job.cpp
Nico Weber 2ca4be97de clang-cl: Implement initial limited support for precompiled headers.
In the gcc precompiled header model, one explicitly runs clang with `-x
c++-header` on a .h file to produce a gch file, and then includes the header
with `-include foo.h` and if a .gch file exists for that header it gets used.
This is documented at
http://clang.llvm.org/docs/UsersManual.html#precompiled-headers

cl.exe's model is fairly different, and controlled by the two flags /Yc and
/Yu. A pch file is generated as a side effect of a regular compilation when
/Ycheader.h is passed. While the compilation is running, the compiler keeps
track of #include lines in the main translation unit and writes everything up
to an `#include "header.h"` line into a pch file. Conversely, /Yuheader.h tells
the compiler to skip all code in the main TU up to and including `#include
"header.h"` and instead load header.pch. (It's also possible to use /Yc and /Yu
without an argument, in that case a `#pragma hrdstop` takes the role of
controlling the point where pch ends and real code begins.)

This patch implements limited support for this in that it requires the pch
header to be passed as a /FI force include flag – with this restriction,
it can be implemented almost completely in the driver with fairly small amounts
of code. For /Yu, this is trivial, and for /Yc a separate pch action is added
that runs before the actual compilation. After r261774, the first failing
command makes a compilation stop – this means if the pch fails to build the
main compilation won't run, which is what we want. However, in /fallback builds
we need to run the main compilation even if the pch build fails so that the
main compilation's fallback can run. To achieve this, add a ForceSuccessCommand
that pretends that the pch build always succeeded in /fallback builds (the main
compilation will then fail to open the pch and run the fallback cl.exe
invocation).

If /Yc /Yu are used in a setup that clang-cl doesn't implement yet, clang-cl
will now emit a "not implemented yet; flag ignored" warning that can be
disabled using -Wno-clang-cl-pch.

Since clang-cl doesn't yet serialize some important things (most notably
`pragma comment(lib, ...)`, this feature is disabled by default and only
enabled by an internal driver flag. Once it's more stable, this internal flag
will disappear.

(The default stdafx.h setup passes stdafx.h as explicit argument to /Yc but not
as /FI – instead every single TU has to `#include <stdafx.h>` as first thing it
does. Implementing support for this should be possible with the approach in
this patch with minimal frontend changes by passing a --stop-at / --start-at
flag from the driver to the frontend. This is left for a follow-up. I don't
think we ever want to support `#pragma hdrstop`, and supporting it with this
approach isn't easy: This approach relies on the driver knowing the pch
filename in advance, and `#pragma hdrstop(out.pch)` can set the output
filename, so the driver can't know about it in advance.)

clang-cl now also honors /Fp and puts pch files in the same spot that cl.exe
would put them, but the pch file format is of course incompatible. This has
ramifications on /fallback, so /Yc /Yu aren't passed through to cl.exe in
/fallback builds.

http://reviews.llvm.org/D17695

llvm-svn: 262420
2016-03-01 23:16:44 +00:00

330 lines
11 KiB
C++

//===--- Job.cpp - Command to Execute -------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "InputInfo.h"
#include "clang/Driver/Driver.h"
#include "clang/Driver/DriverDiagnostic.h"
#include "clang/Driver/Job.h"
#include "clang/Driver/Tool.h"
#include "clang/Driver/ToolChain.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/ADT/StringSwitch.h"
#include "llvm/Support/Program.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
using namespace clang::driver;
using llvm::raw_ostream;
using llvm::StringRef;
using llvm::ArrayRef;
Command::Command(const Action &Source, const Tool &Creator,
const char *Executable, const ArgStringList &Arguments,
ArrayRef<InputInfo> Inputs)
: Source(Source), Creator(Creator), Executable(Executable),
Arguments(Arguments), ResponseFile(nullptr) {
for (const auto &II : Inputs)
if (II.isFilename())
InputFilenames.push_back(II.getFilename());
}
static int skipArgs(const char *Flag, bool HaveCrashVFS) {
// These flags are all of the form -Flag <Arg> and are treated as two
// arguments. Therefore, we need to skip the flag and the next argument.
bool Res = llvm::StringSwitch<bool>(Flag)
.Cases("-I", "-MF", "-MT", "-MQ", true)
.Cases("-o", "-coverage-file", "-dependency-file", true)
.Cases("-fdebug-compilation-dir", "-idirafter", true)
.Cases("-include", "-include-pch", "-internal-isystem", true)
.Cases("-internal-externc-isystem", "-iprefix", "-iwithprefix", true)
.Cases("-iwithprefixbefore", "-isystem", "-iquote", true)
.Cases("-resource-dir", "-serialize-diagnostic-file", true)
.Cases("-dwarf-debug-flags", "-ivfsoverlay", true)
.Cases("-header-include-file", "-diagnostic-log-file", true)
// Some include flags shouldn't be skipped if we have a crash VFS
.Case("-isysroot", !HaveCrashVFS)
.Default(false);
// Match found.
if (Res)
return 2;
// The remaining flags are treated as a single argument.
// These flags are all of the form -Flag and have no second argument.
Res = llvm::StringSwitch<bool>(Flag)
.Cases("-M", "-MM", "-MG", "-MP", "-MD", true)
.Case("-MMD", true)
.Default(false);
// Match found.
if (Res)
return 1;
// These flags are treated as a single argument (e.g., -F<Dir>).
StringRef FlagRef(Flag);
if (FlagRef.startswith("-F") || FlagRef.startswith("-I") ||
FlagRef.startswith("-fmodules-cache-path="))
return 1;
return 0;
}
void Command::printArg(raw_ostream &OS, const char *Arg, bool Quote) {
const bool Escape = std::strpbrk(Arg, "\"\\$");
if (!Quote && !Escape) {
OS << Arg;
return;
}
// Quote and escape. This isn't really complete, but good enough.
OS << '"';
while (const char c = *Arg++) {
if (c == '"' || c == '\\' || c == '$')
OS << '\\';
OS << c;
}
OS << '"';
}
void Command::writeResponseFile(raw_ostream &OS) const {
// In a file list, we only write the set of inputs to the response file
if (Creator.getResponseFilesSupport() == Tool::RF_FileList) {
for (const char *Arg : InputFileList) {
OS << Arg << '\n';
}
return;
}
// In regular response files, we send all arguments to the response file.
// Wrapping all arguments in double quotes ensures that both Unix tools and
// Windows tools understand the response file.
for (const char *Arg : Arguments) {
OS << '"';
for (; *Arg != '\0'; Arg++) {
if (*Arg == '\"' || *Arg == '\\') {
OS << '\\';
}
OS << *Arg;
}
OS << "\" ";
}
}
void Command::buildArgvForResponseFile(
llvm::SmallVectorImpl<const char *> &Out) const {
// When not a file list, all arguments are sent to the response file.
// This leaves us to set the argv to a single parameter, requesting the tool
// to read the response file.
if (Creator.getResponseFilesSupport() != Tool::RF_FileList) {
Out.push_back(Executable);
Out.push_back(ResponseFileFlag.c_str());
return;
}
llvm::StringSet<> Inputs;
for (const char *InputName : InputFileList)
Inputs.insert(InputName);
Out.push_back(Executable);
// In a file list, build args vector ignoring parameters that will go in the
// response file (elements of the InputFileList vector)
bool FirstInput = true;
for (const char *Arg : Arguments) {
if (Inputs.count(Arg) == 0) {
Out.push_back(Arg);
} else if (FirstInput) {
FirstInput = false;
Out.push_back(Creator.getResponseFileFlag());
Out.push_back(ResponseFile);
}
}
}
void Command::Print(raw_ostream &OS, const char *Terminator, bool Quote,
CrashReportInfo *CrashInfo) const {
// Always quote the exe.
OS << ' ';
printArg(OS, Executable, /*Quote=*/true);
llvm::ArrayRef<const char *> Args = Arguments;
llvm::SmallVector<const char *, 128> ArgsRespFile;
if (ResponseFile != nullptr) {
buildArgvForResponseFile(ArgsRespFile);
Args = ArrayRef<const char *>(ArgsRespFile).slice(1); // no executable name
}
bool HaveCrashVFS = CrashInfo && !CrashInfo->VFSPath.empty();
for (size_t i = 0, e = Args.size(); i < e; ++i) {
const char *const Arg = Args[i];
if (CrashInfo) {
if (int Skip = skipArgs(Arg, HaveCrashVFS)) {
i += Skip - 1;
continue;
}
auto Found = std::find_if(InputFilenames.begin(), InputFilenames.end(),
[&Arg](StringRef IF) { return IF == Arg; });
if (Found != InputFilenames.end() &&
(i == 0 || StringRef(Args[i - 1]) != "-main-file-name")) {
// Replace the input file name with the crashinfo's file name.
OS << ' ';
StringRef ShortName = llvm::sys::path::filename(CrashInfo->Filename);
printArg(OS, ShortName.str().c_str(), Quote);
continue;
}
}
OS << ' ';
printArg(OS, Arg, Quote);
}
if (CrashInfo && HaveCrashVFS) {
OS << ' ';
printArg(OS, "-ivfsoverlay", Quote);
OS << ' ';
printArg(OS, CrashInfo->VFSPath.str().c_str(), Quote);
}
if (ResponseFile != nullptr) {
OS << "\n Arguments passed via response file:\n";
writeResponseFile(OS);
// Avoiding duplicated newline terminator, since FileLists are
// newline-separated.
if (Creator.getResponseFilesSupport() != Tool::RF_FileList)
OS << "\n";
OS << " (end of response file)";
}
OS << Terminator;
}
void Command::setResponseFile(const char *FileName) {
ResponseFile = FileName;
ResponseFileFlag = Creator.getResponseFileFlag();
ResponseFileFlag += FileName;
}
int Command::Execute(const StringRef **Redirects, std::string *ErrMsg,
bool *ExecutionFailed) const {
SmallVector<const char*, 128> Argv;
if (ResponseFile == nullptr) {
Argv.push_back(Executable);
Argv.append(Arguments.begin(), Arguments.end());
Argv.push_back(nullptr);
return llvm::sys::ExecuteAndWait(Executable, Argv.data(), /*env*/ nullptr,
Redirects, /*secondsToWait*/ 0,
/*memoryLimit*/ 0, ErrMsg,
ExecutionFailed);
}
// We need to put arguments in a response file (command is too large)
// Open stream to store the response file contents
std::string RespContents;
llvm::raw_string_ostream SS(RespContents);
// Write file contents and build the Argv vector
writeResponseFile(SS);
buildArgvForResponseFile(Argv);
Argv.push_back(nullptr);
SS.flush();
// Save the response file in the appropriate encoding
if (std::error_code EC = writeFileWithEncoding(
ResponseFile, RespContents, Creator.getResponseFileEncoding())) {
if (ErrMsg)
*ErrMsg = EC.message();
if (ExecutionFailed)
*ExecutionFailed = true;
return -1;
}
return llvm::sys::ExecuteAndWait(Executable, Argv.data(), /*env*/ nullptr,
Redirects, /*secondsToWait*/ 0,
/*memoryLimit*/ 0, ErrMsg, ExecutionFailed);
}
FallbackCommand::FallbackCommand(const Action &Source_, const Tool &Creator_,
const char *Executable_,
const ArgStringList &Arguments_,
ArrayRef<InputInfo> Inputs,
std::unique_ptr<Command> Fallback_)
: Command(Source_, Creator_, Executable_, Arguments_, Inputs),
Fallback(std::move(Fallback_)) {}
void FallbackCommand::Print(raw_ostream &OS, const char *Terminator,
bool Quote, CrashReportInfo *CrashInfo) const {
Command::Print(OS, "", Quote, CrashInfo);
OS << " ||";
Fallback->Print(OS, Terminator, Quote, CrashInfo);
}
static bool ShouldFallback(int ExitCode) {
// FIXME: We really just want to fall back for internal errors, such
// as when some symbol cannot be mangled, when we should be able to
// parse something but can't, etc.
return ExitCode != 0;
}
int FallbackCommand::Execute(const StringRef **Redirects, std::string *ErrMsg,
bool *ExecutionFailed) const {
int PrimaryStatus = Command::Execute(Redirects, ErrMsg, ExecutionFailed);
if (!ShouldFallback(PrimaryStatus))
return PrimaryStatus;
// Clear ExecutionFailed and ErrMsg before falling back.
if (ErrMsg)
ErrMsg->clear();
if (ExecutionFailed)
*ExecutionFailed = false;
const Driver &D = getCreator().getToolChain().getDriver();
D.Diag(diag::warn_drv_invoking_fallback) << Fallback->getExecutable();
int SecondaryStatus = Fallback->Execute(Redirects, ErrMsg, ExecutionFailed);
return SecondaryStatus;
}
ForceSuccessCommand::ForceSuccessCommand(const Action &Source_,
const Tool &Creator_,
const char *Executable_,
const ArgStringList &Arguments_,
ArrayRef<InputInfo> Inputs)
: Command(Source_, Creator_, Executable_, Arguments_, Inputs) {}
void ForceSuccessCommand::Print(raw_ostream &OS, const char *Terminator,
bool Quote, CrashReportInfo *CrashInfo) const {
Command::Print(OS, "", Quote, CrashInfo);
OS << " || (exit 0)" << Terminator;
}
int ForceSuccessCommand::Execute(const StringRef **Redirects,
std::string *ErrMsg,
bool *ExecutionFailed) const {
int Status = Command::Execute(Redirects, ErrMsg, ExecutionFailed);
(void)Status;
if (ExecutionFailed)
*ExecutionFailed = false;
return 0;
}
void JobList::Print(raw_ostream &OS, const char *Terminator, bool Quote,
CrashReportInfo *CrashInfo) const {
for (const auto &Job : *this)
Job.Print(OS, Terminator, Quote, CrashInfo);
}
void JobList::clear() { Jobs.clear(); }