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//===-- HeaderIncludeGen.cpp - Generate Header Includes -------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "clang/Frontend/DependencyOutputOptions.h"
#include "clang/Frontend/Utils.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Frontend/FrontendDiagnostic.h"
#include "clang/Lex/Preprocessor.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
namespace {
class HeaderIncludesCallback : public PPCallbacks {
SourceManager &SM;
raw_ostream *OutputFile;
const DependencyOutputOptions &DepOpts;
unsigned CurrentIncludeDepth;
bool HasProcessedPredefines;
bool OwnsOutputFile;
bool ShowAllHeaders;
bool ShowDepth;
bool MSStyle;
public:
HeaderIncludesCallback(const Preprocessor *PP, bool ShowAllHeaders_,
raw_ostream *OutputFile_,
const DependencyOutputOptions &DepOpts,
bool OwnsOutputFile_, bool ShowDepth_, bool MSStyle_)
: SM(PP->getSourceManager()), OutputFile(OutputFile_), DepOpts(DepOpts),
CurrentIncludeDepth(0), HasProcessedPredefines(false),
OwnsOutputFile(OwnsOutputFile_), ShowAllHeaders(ShowAllHeaders_),
ShowDepth(ShowDepth_), MSStyle(MSStyle_) {}
~HeaderIncludesCallback() override {
if (OwnsOutputFile)
delete OutputFile;
}
void FileChanged(SourceLocation Loc, FileChangeReason Reason,
SrcMgr::CharacteristicKind FileType,
FileID PrevFID) override;
};
}
static void PrintHeaderInfo(raw_ostream *OutputFile, StringRef Filename,
bool ShowDepth, unsigned CurrentIncludeDepth,
bool MSStyle) {
// Write to a temporary string to avoid unnecessary flushing on errs().
SmallString<512> Pathname(Filename);
if (!MSStyle)
Lexer::Stringify(Pathname);
SmallString<256> Msg;
if (MSStyle)
Msg += "Note: including file:";
if (ShowDepth) {
// The main source file is at depth 1, so skip one dot.
for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
Msg += MSStyle ? ' ' : '.';
if (!MSStyle)
Msg += ' ';
}
Msg += Pathname;
Msg += '\n';
*OutputFile << Msg;
OutputFile->flush();
}
void clang::AttachHeaderIncludeGen(Preprocessor &PP,
const DependencyOutputOptions &DepOpts,
bool ShowAllHeaders, StringRef OutputPath,
bool ShowDepth, bool MSStyle) {
raw_ostream *OutputFile = &llvm::errs();
bool OwnsOutputFile = false;
// Choose output stream, when printing in cl.exe /showIncludes style.
if (MSStyle) {
switch (DepOpts.ShowIncludesDest) {
default:
llvm_unreachable("Invalid destination for /showIncludes output!");
case ShowIncludesDestination::Stderr:
OutputFile = &llvm::errs();
break;
case ShowIncludesDestination::Stdout:
OutputFile = &llvm::outs();
break;
}
}
// Open the output file, if used.
if (!OutputPath.empty()) {
std::error_code EC;
llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
OutputPath.str(), EC,
llvm::sys::fs::OF_Append | llvm::sys::fs::OF_Text);
if (EC) {
PP.getDiagnostics().Report(clang::diag::warn_fe_cc_print_header_failure)
<< EC.message();
delete OS;
} else {
OS->SetUnbuffered();
OutputFile = OS;
OwnsOutputFile = true;
}
}
// Print header info for extra headers, pretending they were discovered by
// the regular preprocessor. The primary use case is to support proper
// generation of Make / Ninja file dependencies for implicit includes, such
// as sanitizer blacklists. It's only important for cl.exe compatibility,
// the GNU way to generate rules is -M / -MM / -MD / -MMD.
for (const auto &Header : DepOpts.ExtraDeps)
PrintHeaderInfo(OutputFile, Header, ShowDepth, 2, MSStyle);
PP.addPPCallbacks(std::make_unique<HeaderIncludesCallback>(
&PP, ShowAllHeaders, OutputFile, DepOpts, OwnsOutputFile, ShowDepth,
MSStyle));
}
void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
FileChangeReason Reason,
SrcMgr::CharacteristicKind NewFileType,
FileID PrevFID) {
// Unless we are exiting a #include, make sure to skip ahead to the line the
// #include directive was at.
PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
if (UserLoc.isInvalid())
return;
// Adjust the current include depth.
if (Reason == PPCallbacks::EnterFile) {
++CurrentIncludeDepth;
} else if (Reason == PPCallbacks::ExitFile) {
if (CurrentIncludeDepth)
--CurrentIncludeDepth;
// We track when we are done with the predefines by watching for the first
// place where we drop back to a nesting depth of 1.
if (CurrentIncludeDepth == 1 && !HasProcessedPredefines) {
if (!DepOpts.ShowIncludesPretendHeader.empty()) {
PrintHeaderInfo(OutputFile, DepOpts.ShowIncludesPretendHeader,
ShowDepth, 2, MSStyle);
}
HasProcessedPredefines = true;
}
return;
} else
return;
// Show the header if we are (a) past the predefines, or (b) showing all
// headers and in the predefines at a depth past the initial file and command
// line buffers.
bool ShowHeader = (HasProcessedPredefines ||
(ShowAllHeaders && CurrentIncludeDepth > 2));
unsigned IncludeDepth = CurrentIncludeDepth;
if (!HasProcessedPredefines)
--IncludeDepth; // Ignore indent from <built-in>.
else if (!DepOpts.ShowIncludesPretendHeader.empty())
++IncludeDepth; // Pretend inclusion by ShowIncludesPretendHeader.
if (!DepOpts.IncludeSystemHeaders && isSystem(NewFileType))
ShowHeader = false;
// Dump the header include information we are past the predefines buffer or
// are showing all headers and this isn't the magic implicit <command line>
// header.
// FIXME: Identify headers in a more robust way than comparing their name to
// "<command line>" and "<built-in>" in a bunch of places.
if (ShowHeader && Reason == PPCallbacks::EnterFile &&
UserLoc.getFilename() != StringRef("<command line>")) {
PrintHeaderInfo(OutputFile, UserLoc.getFilename(), ShowDepth, IncludeDepth,
MSStyle);
}
}