dmantipov updated this revision to Diff 293949.
dmantipov added a comment.
IIUC compiler driver is not intended to be multithreaded. But OK, here is the
version with llvm::call_once(...).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D87187/new/
https://reviews.llvm.org/D87187
Files:
clang/include/clang/Driver/Distro.h
clang/lib/Driver/Distro.cpp
Index: clang/lib/Driver/Distro.cpp
===================================================================
--- clang/lib/Driver/Distro.cpp
+++ clang/lib/Driver/Distro.cpp
@@ -15,69 +15,100 @@
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Threading.h"
using namespace clang::driver;
using namespace clang;
-static Distro::DistroType DetectDistro(llvm::vfs::FileSystem &VFS,
- const llvm::Triple &TargetOrHost) {
- // If we don't target Linux, no need to check the distro. This saves a few
- // OS calls.
- if (!TargetOrHost.isOSLinux())
+static Distro::DistroType DetectOsRelease(llvm::vfs::FileSystem &VFS) {
+ llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> File =
+ VFS.getBufferForFile("/etc/os-release");
+ if (!File)
+ File = VFS.getBufferForFile("/usr/lib/os-release");
+ if (!File)
return Distro::UnknownDistro;
- // If the host is not running Linux, and we're backed by a real file system,
- // no need to check the distro. This is the case where someone is
- // cross-compiling from BSD or Windows to Linux, and it would be meaningless
- // to try to figure out the "distro" of the non-Linux host.
- IntrusiveRefCntPtr<llvm::vfs::FileSystem> RealFS =
- llvm::vfs::getRealFileSystem();
- llvm::Triple HostTriple(llvm::sys::getProcessTriple());
- if (!HostTriple.isOSLinux() && &VFS == RealFS.get())
- return Distro::UnknownDistro;
+ SmallVector<StringRef, 16> Lines;
+ File.get()->getBuffer().split(Lines, "\n");
+ Distro::DistroType Version = Distro::UnknownDistro;
+
+ // Obviously this can be improved a lot.
+ for (StringRef Line : Lines)
+ if (Version == Distro::UnknownDistro && Line.startswith("ID="))
+ Version = llvm::StringSwitch<Distro::DistroType>(Line.substr(3))
+ .Case("fedora", Distro::Fedora)
+ .Case("gentoo", Distro::Gentoo)
+ .Case("arch", Distro::ArchLinux)
+ // On SLES, /etc/os-release was introduced in SLES 11.
+ .Case("sles", Distro::OpenSUSE)
+ .Case("opensuse", Distro::OpenSUSE)
+ .Case("exherbo", Distro::Exherbo)
+ .Default(Distro::UnknownDistro);
+ return Version;
+}
+static Distro::DistroType DetectLsbRelease(llvm::vfs::FileSystem &VFS) {
llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> File =
VFS.getBufferForFile("/etc/lsb-release");
- if (File) {
- StringRef Data = File.get()->getBuffer();
- SmallVector<StringRef, 16> Lines;
- Data.split(Lines, "\n");
- Distro::DistroType Version = Distro::UnknownDistro;
- for (StringRef Line : Lines)
- if (Version == Distro::UnknownDistro && Line.startswith("DISTRIB_CODENAME="))
- Version = llvm::StringSwitch<Distro::DistroType>(Line.substr(17))
- .Case("hardy", Distro::UbuntuHardy)
- .Case("intrepid", Distro::UbuntuIntrepid)
- .Case("jaunty", Distro::UbuntuJaunty)
- .Case("karmic", Distro::UbuntuKarmic)
- .Case("lucid", Distro::UbuntuLucid)
- .Case("maverick", Distro::UbuntuMaverick)
- .Case("natty", Distro::UbuntuNatty)
- .Case("oneiric", Distro::UbuntuOneiric)
- .Case("precise", Distro::UbuntuPrecise)
- .Case("quantal", Distro::UbuntuQuantal)
- .Case("raring", Distro::UbuntuRaring)
- .Case("saucy", Distro::UbuntuSaucy)
- .Case("trusty", Distro::UbuntuTrusty)
- .Case("utopic", Distro::UbuntuUtopic)
- .Case("vivid", Distro::UbuntuVivid)
- .Case("wily", Distro::UbuntuWily)
- .Case("xenial", Distro::UbuntuXenial)
- .Case("yakkety", Distro::UbuntuYakkety)
- .Case("zesty", Distro::UbuntuZesty)
- .Case("artful", Distro::UbuntuArtful)
- .Case("bionic", Distro::UbuntuBionic)
- .Case("cosmic", Distro::UbuntuCosmic)
- .Case("disco", Distro::UbuntuDisco)
- .Case("eoan", Distro::UbuntuEoan)
- .Case("focal", Distro::UbuntuFocal)
- .Case("groovy", Distro::UbuntuGroovy)
- .Default(Distro::UnknownDistro);
- if (Version != Distro::UnknownDistro)
- return Version;
- }
+ if (!File)
+ return Distro::UnknownDistro;
+
+ SmallVector<StringRef, 16> Lines;
+ File.get()->getBuffer().split(Lines, "\n");
+ Distro::DistroType Version = Distro::UnknownDistro;
+
+ for (StringRef Line : Lines)
+ if (Version == Distro::UnknownDistro &&
+ Line.startswith("DISTRIB_CODENAME="))
+ Version = llvm::StringSwitch<Distro::DistroType>(Line.substr(17))
+ .Case("hardy", Distro::UbuntuHardy)
+ .Case("intrepid", Distro::UbuntuIntrepid)
+ .Case("jaunty", Distro::UbuntuJaunty)
+ .Case("karmic", Distro::UbuntuKarmic)
+ .Case("lucid", Distro::UbuntuLucid)
+ .Case("maverick", Distro::UbuntuMaverick)
+ .Case("natty", Distro::UbuntuNatty)
+ .Case("oneiric", Distro::UbuntuOneiric)
+ .Case("precise", Distro::UbuntuPrecise)
+ .Case("quantal", Distro::UbuntuQuantal)
+ .Case("raring", Distro::UbuntuRaring)
+ .Case("saucy", Distro::UbuntuSaucy)
+ .Case("trusty", Distro::UbuntuTrusty)
+ .Case("utopic", Distro::UbuntuUtopic)
+ .Case("vivid", Distro::UbuntuVivid)
+ .Case("wily", Distro::UbuntuWily)
+ .Case("xenial", Distro::UbuntuXenial)
+ .Case("yakkety", Distro::UbuntuYakkety)
+ .Case("zesty", Distro::UbuntuZesty)
+ .Case("artful", Distro::UbuntuArtful)
+ .Case("bionic", Distro::UbuntuBionic)
+ .Case("cosmic", Distro::UbuntuCosmic)
+ .Case("disco", Distro::UbuntuDisco)
+ .Case("eoan", Distro::UbuntuEoan)
+ .Case("focal", Distro::UbuntuFocal)
+ .Case("groovy", Distro::UbuntuGroovy)
+ .Default(Distro::UnknownDistro);
+ return Version;
+}
+
+static Distro::DistroType DetectDistro(llvm::vfs::FileSystem &VFS) {
+ Distro::DistroType Version = Distro::UnknownDistro;
+
+ // Newer freedesktop.org's compilant systemd-based systems
+ // should provide /etc/os-release or /usr/lib/os-release.
+ Version = DetectOsRelease(VFS);
+ if (Version != Distro::UnknownDistro)
+ return Version;
+
+ // Older systems might provide /etc/lsb-release.
+ Version = DetectLsbRelease(VFS);
+ if (Version != Distro::UnknownDistro)
+ return Version;
+
+ // Otherwise try some distro-specific quirks for RedHat...
+ llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> File =
+ VFS.getBufferForFile("/etc/redhat-release");
- File = VFS.getBufferForFile("/etc/redhat-release");
if (File) {
StringRef Data = File.get()->getBuffer();
if (Data.startswith("Fedora release"))
@@ -95,6 +126,7 @@
return Distro::UnknownDistro;
}
+ // ...for Debian
File = VFS.getBufferForFile("/etc/debian_version");
if (File) {
StringRef Data = File.get()->getBuffer();
@@ -130,6 +162,7 @@
.Default(Distro::UnknownDistro);
}
+ // ...for SUSE
File = VFS.getBufferForFile("/etc/SuSE-release");
if (File) {
StringRef Data = File.get()->getBuffer();
@@ -153,6 +186,7 @@
return Distro::UnknownDistro;
}
+ // ...and others.
if (VFS.exists("/etc/exherbo-release"))
return Distro::Exherbo;
@@ -168,5 +202,36 @@
return Distro::UnknownDistro;
}
+static Distro::DistroType GetDistro(llvm::vfs::FileSystem &VFS,
+ const llvm::Triple &TargetOrHost) {
+ // If we don't target Linux, no need to check the distro. This saves a few
+ // OS calls.
+ if (!TargetOrHost.isOSLinux())
+ return Distro::UnknownDistro;
+
+ // True if we're backed by a real file system.
+ const bool onRealFS = (llvm::vfs::getRealFileSystem() == &VFS);
+
+ // If the host is not running Linux, and we're backed by a real file
+ // system, no need to check the distro. This is the case where someone
+ // is cross-compiling from BSD or Windows to Linux, and it would be
+ // meaningless to try to figure out the "distro" of the non-Linux host.
+ llvm::Triple HostTriple(llvm::sys::getProcessTriple());
+ if (!HostTriple.isOSLinux() && onRealFS)
+ return Distro::UnknownDistro;
+
+ if (onRealFS) {
+ static Distro::DistroType LinuxDistro = Distro::UninitializedDistro;
+ static llvm::once_flag DistroDetectFlag;
+ // If we're backed by a real file system, perform
+ // the detection only once and save the result.
+ llvm::call_once(DistroDetectFlag, [&VFS]() {
+ LinuxDistro = DetectDistro(VFS);
+ });
+ return LinuxDistro;
+ }
+ return Distro::UnknownDistro;
+}
+
Distro::Distro(llvm::vfs::FileSystem &VFS, const llvm::Triple &TargetOrHost)
- : DistroVal(DetectDistro(VFS, TargetOrHost)) {}
+ : DistroVal(GetDistro(VFS, TargetOrHost)) {}
Index: clang/include/clang/Driver/Distro.h
===================================================================
--- clang/include/clang/Driver/Distro.h
+++ clang/include/clang/Driver/Distro.h
@@ -23,6 +23,8 @@
class Distro {
public:
enum DistroType {
+ // Special value means that no detection was performed yet.
+ UninitializedDistro,
// NB: Releases of a particular Linux distro should be kept together
// in this enum, because some tests are done by integer comparison against
// the first and last known member in the family, e.g. IsRedHat().
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