From 48cd9d9dd86c2c37e6c47cbb23c06d36a1870b83 Mon Sep 17 00:00:00 2001 From: Pavel Labath Date: Wed, 3 Jun 2020 12:08:45 +0200 Subject: [Support] Use outs() in ToolOutputFile Summary: If the output filename was specified as "-", the ToolOutputFile class would create a brand new raw_ostream object referring to the stdout. This patch changes it to reuse the llvm::outs() singleton. At the moment, this change should be "NFC", but it does enable other enhancements, like the automatic stdout/stderr synchronization as discussed on D80803. I've checked the history, and I did not find any indication that this class *has* to use a brand new stream object instead of outs() -- indeed, it is special-casing "-" in a number of places already, so this change fits the pattern pretty well. I suspect the main reason for the current state of affairs is that the class was originally introduced (r111595, in 2010) as a raw_fd_ostream subclass, which made any other solution impossible. Another potential benefit of this patch is that it makes it possible to move the raw_ostream class out of the business of special-casing "-" for stdout handling. That state of affairs does not seem appropriate because "-" is a valid filename (albeit hard to access with a lot of command line tools) on most systems. Handling "-" in ToolOutputFile seems more appropriate. To make this possible, this patch changes the return type of llvm::outs() and errs() to raw_fd_ostream&. Previously the functions were constructing objects of that type, but returning a generic raw_ostream reference. This makes it possible for new ToolOutputFile and other code to use raw_fd_ostream methods like error() on the outs() object. This does not seem like a bad thing (since stdout is a file descriptor which can be redirected to anywhere, it makes sense to ask it whether the writing was successful or if it supports seeking), and indeed a lot of code was already depending on this fact via the ToolOutputFile "back door". Reviewers: dblaikie, JDevlieghere, MaskRay, jhenderson Subscribers: hiraditya, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D81078 --- llvm/lib/Support/ToolOutputFile.cpp | 26 ++++++++++++++++++++------ 1 file changed, 20 insertions(+), 6 deletions(-) (limited to 'llvm/lib/Support/ToolOutputFile.cpp') diff --git a/llvm/lib/Support/ToolOutputFile.cpp b/llvm/lib/Support/ToolOutputFile.cpp index 1051af3..c2ca97a 100644 --- a/llvm/lib/Support/ToolOutputFile.cpp +++ b/llvm/lib/Support/ToolOutputFile.cpp @@ -15,31 +15,45 @@ #include "llvm/Support/Signals.h" using namespace llvm; +static bool isStdout(StringRef Filename) { return Filename == "-"; } + ToolOutputFile::CleanupInstaller::CleanupInstaller(StringRef Filename) : Filename(std::string(Filename)), Keep(false) { // Arrange for the file to be deleted if the process is killed. - if (Filename != "-") + if (!isStdout(Filename)) sys::RemoveFileOnSignal(Filename); } ToolOutputFile::CleanupInstaller::~CleanupInstaller() { + if (isStdout(Filename)) + return; + // Delete the file if the client hasn't told us not to. - if (!Keep && Filename != "-") + if (!Keep) sys::fs::remove(Filename); // Ok, the file is successfully written and closed, or deleted. There's no // further need to clean it up on signals. - if (Filename != "-") - sys::DontRemoveFileOnSignal(Filename); + sys::DontRemoveFileOnSignal(Filename); } ToolOutputFile::ToolOutputFile(StringRef Filename, std::error_code &EC, sys::fs::OpenFlags Flags) - : Installer(Filename), OS(Filename, EC, Flags) { + : Installer(Filename) { + if (isStdout(Filename)) { + OS = &outs(); + EC = std::error_code(); + return; + } + OSHolder.emplace(Filename, EC, Flags); + OS = OSHolder.getPointer(); // If open fails, no cleanup is needed. if (EC) Installer.Keep = true; } ToolOutputFile::ToolOutputFile(StringRef Filename, int FD) - : Installer(Filename), OS(FD, true) {} + : Installer(Filename) { + OSHolder.emplace(FD, true); + OS = OSHolder.getPointer(); +} -- cgit v1.1