Restructure how the driver communicates information about the

target Objective-C runtime down to the frontend:  break this
down into a single target runtime kind and version, and compute
all the relevant information from that.  This makes it
relatively painless to add support for new runtimes to the
compiler.  Make the new -cc1 flag, -fobjc-runtime=blah-x.y.z,
available at the driver level as a better and more general
alternative to -fgnu-runtime and -fnext-runtime.  This new
concept of an Objective-C runtime also encompasses what we
were previously separating out as the "Objective-C ABI", so
fragile vs. non-fragile runtimes are now really modelled as
different kinds of runtime, paving the way for better overall
differentiation.

As a sort of special case, continue to accept the -cc1 flag
-fobjc-runtime-has-weak, as a sop to PLCompatibilityWeak.

I won't go so far as to say "no functionality change", even
ignoring the new driver flag, but subtle changes in driver
semantics are almost certainly not intended.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158793 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 132 insertions, 0 deletions

diff --git a/lib/Basic/CMakeLists.txt b/lib/Basic/CMakeLists.txt
index ef2e93c49c..ff661fd70b 100644
--- a/lib/Basic/CMakeLists.txt
+++ b/lib/Basic/CMakeLists.txt
@@ -10,6 +10,7 @@ add_clang_library(clangBasic
   IdentifierTable.cpp
   LangOptions.cpp
   Module.cpp
+  ObjCRuntime.cpp
   SourceLocation.cpp
   SourceManager.cpp
   TargetInfo.cpp
diff --git a/lib/Basic/ObjCRuntime.cpp b/lib/Basic/ObjCRuntime.cpp
new file mode 100644
index 0000000000..d92adbcb46
--- /dev/null
+++ b/lib/Basic/ObjCRuntime.cpp
@@ -0,0 +1,79 @@
+//===- ObjCRuntime.cpp - Objective-C Runtime Handling -----------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the ObjCRuntime class, which represents the
+// target Objective-C runtime.
+//
+//===----------------------------------------------------------------------===//
+#include "clang/Basic/ObjCRuntime.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+
+std::string ObjCRuntime::getAsString() const {
+  std::string Result;
+  {
+    llvm::raw_string_ostream Out(Result);
+    Out << *this;
+  }
+  return Result;  
+}
+
+raw_ostream &clang::operator<<(raw_ostream &out, const ObjCRuntime &value) {
+  switch (value.getKind()) {
+  case ObjCRuntime::MacOSX: out << "macosx"; break;
+  case ObjCRuntime::FragileMacOSX: out << "macosx-fragile"; break;
+  case ObjCRuntime::iOS: out << "ios"; break;
+  case ObjCRuntime::GNU: out << "gnu"; break;
+  case ObjCRuntime::FragileGNU: out << "gnu-fragile"; break;
+  }
+  if (value.getVersion() > VersionTuple(0)) {
+    out << '-' << value.getVersion();
+  }
+  return out;
+}
+
+bool ObjCRuntime::tryParse(StringRef input) {
+  // Look for the last dash.
+  std::size_t dash = input.rfind('-');
+
+  // We permit (1) dashes in the runtime name and (2) the version to
+  // be omitted, so ignore dashes that aren't followed by a digit.
+  if (dash != StringRef::npos && dash + 1 != input.size() &&
+      (input[dash+1] < '0' || input[dash+1] > '9')) {
+    dash = StringRef::npos;
+  }
+
+  // Everything prior to that must be a valid string name.
+  Kind kind;
+  StringRef runtimeName = input.substr(0, dash);
+  if (runtimeName == "macosx") {
+    kind = ObjCRuntime::MacOSX;
+  } else if (runtimeName == "macosx-fragile") {
+    kind = ObjCRuntime::FragileMacOSX;
+  } else if (runtimeName == "ios") {
+    kind = ObjCRuntime::iOS;
+  } else if (runtimeName == "gnu") {
+    kind = ObjCRuntime::GNU;
+  } else if (runtimeName == "gnu-fragile") {
+    kind = ObjCRuntime::FragileGNU;
+  } else {
+    return true;
+  }
+  TheKind = kind;
+  
+  Version = VersionTuple(0);
+  if (dash != StringRef::npos) {
+    StringRef verString = input.substr(dash + 1);
+    if (Version.tryParse(verString)) 
+      return true;
+  }
+
+  return false;
+}
diff --git a/lib/Basic/VersionTuple.cpp b/lib/Basic/VersionTuple.cpp
index 77aad39cbf..4f479d00d6 100644
--- a/lib/Basic/VersionTuple.cpp
+++ b/lib/Basic/VersionTuple.cpp
@@ -34,3 +34,55 @@ raw_ostream& clang::operator<<(raw_ostream &Out,
     Out << '.' << *Subminor;
   return Out;
 }
+
+static bool parseInt(StringRef &input, unsigned &value) {
+  assert(value == 0);
+  if (input.empty()) return true;
+
+  char next = input[0];
+  input = input.substr(1);
+  if (next < '0' || next > '9') return true;
+  value = (unsigned) (next - '0');
+
+  while (!input.empty()) {
+    next = input[0];
+    if (next < '0' || next > '9') return false;
+    input = input.substr(1);
+    value = value * 10 + (unsigned) (next - '0');
+  }
+
+  return false;
+}
+
+bool VersionTuple::tryParse(StringRef input) {
+  unsigned major = 0, minor = 0, micro = 0;
+
+  // Parse the major version, [0-9]+
+  if (parseInt(input, major)) return true;
+
+  if (input.empty()) {
+    *this = VersionTuple(major);
+    return false;
+  }
+
+  // If we're not done, parse the minor version, \.[0-9]+
+  if (input[0] != '.') return true;
+  input = input.substr(1);
+  if (parseInt(input, minor)) return true;
+
+  if (input.empty()) {
+    *this = VersionTuple(major, minor);
+    return false;
+  }
+
+  // If we're not done, parse the micro version, \.[0-9]+
+  if (input[0] != '.') return true;
+  input = input.substr(1);
+  if (parseInt(input, micro)) return true;
+
+  // If we have characters left over, it's an error.
+  if (!input.empty()) return true;
+
+  *this = VersionTuple(major, minor, micro);
+  return false;
+}