commit 9c42a8d43e04084b4613c83469d6cdb70d789322
author Erik Pilkington <erik.pilkington@gmail.com> Thu Feb 23 21:08:08 2017 +0000
committer Erik Pilkington <erik.pilkington@gmail.com> Thu Feb 23 21:08:08 2017 +0000
tree 2aea639e341cf69c90411e7913c6512b3ca72b01
parent ee2d77f6d693b88a335f34d559d7f82fb6998859

[ObjC][CodeGen] CodeGen support for @available.

CodeGens uses of @available into calls to the compiler-rt function
__isOSVersionAtLeast.

This commit is part of a feature that I proposed here:
http://lists.llvm.org/pipermail/cfe-dev/2016-July/049851.html

Differential revision: https://reviews.llvm.org/D27827

llvm-svn: 296015

clang/lib/CodeGen/CGExprScalar.cpp

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 12b14be..63031d4 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -300,6 +300,24 @@
     return V;
   }
 
+  Value *VisitObjCAvailabilityCheckExpr(ObjCAvailabilityCheckExpr *E) {
+    VersionTuple Version = E->getVersion();
+
+    // If we're checking for a platform older than our minimum deployment
+    // target, we can fold the check away.
+    if (Version <= CGF.CGM.getTarget().getPlatformMinVersion())
+      return llvm::ConstantInt::get(Builder.getInt1Ty(), 1);
+
+    Optional<unsigned> Min = Version.getMinor(), SMin = Version.getSubminor();
+    llvm::Value *Args[] = {
+        llvm::ConstantInt::get(CGF.CGM.Int32Ty, Version.getMajor()),
+        llvm::ConstantInt::get(CGF.CGM.Int32Ty, Min ? *Min : 0),
+        llvm::ConstantInt::get(CGF.CGM.Int32Ty, SMin ? *SMin : 0),
+    };
+
+    return CGF.EmitBuiltinAvailable(Args);
+  }
+
   Value *VisitArraySubscriptExpr(ArraySubscriptExpr *E);
   Value *VisitShuffleVectorExpr(ShuffleVectorExpr *E);
   Value *VisitConvertVectorExpr(ConvertVectorExpr *E);

clang/lib/CodeGen/CGObjC.cpp

diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index 913a2ea..adeb6d1 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -3399,5 +3399,21 @@
   return Val;
 }
 
+llvm::Value *
+CodeGenFunction::EmitBuiltinAvailable(ArrayRef<llvm::Value *> Args) {
+  assert(Args.size() == 3 && "Expected 3 argument here!");
+
+  if (!CGM.IsOSVersionAtLeastFn) {
+    llvm::FunctionType *FTy =
+        llvm::FunctionType::get(Int32Ty, {Int32Ty, Int32Ty, Int32Ty}, false);
+    CGM.IsOSVersionAtLeastFn =
+        CGM.CreateRuntimeFunction(FTy, "__isOSVersionAtLeast");
+  }
+
+  llvm::Value *CallRes =
+      EmitNounwindRuntimeCall(CGM.IsOSVersionAtLeastFn, Args);
+
+  return Builder.CreateICmpNE(CallRes, llvm::Constant::getNullValue(Int32Ty));
+}
 
 CGObjCRuntime::~CGObjCRuntime() {}

clang/lib/CodeGen/CodeGenFunction.h

diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 252561f..3bb8088 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -3169,6 +3169,8 @@
 public:
   llvm::Value *EmitMSVCBuiltinExpr(MSVCIntrin BuiltinID, const CallExpr *E);
 
+  llvm::Value *EmitBuiltinAvailable(ArrayRef<llvm::Value *> Args);
+
   llvm::Value *EmitObjCProtocolExpr(const ObjCProtocolExpr *E);
   llvm::Value *EmitObjCStringLiteral(const ObjCStringLiteral *E);
   llvm::Value *EmitObjCBoxedExpr(const ObjCBoxedExpr *E);

clang/lib/CodeGen/CodeGenModule.h

diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index 465d0b4..8faebe1 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -546,6 +546,10 @@
     return *ObjCData;
   }
 
+  // Version checking function, used to implement ObjC's @available:
+  // i32 @__isOSVersionAtLeast(i32, i32, i32)
+  llvm::Constant *IsOSVersionAtLeastFn = nullptr;
+
   InstrProfStats &getPGOStats() { return PGOStats; }
   llvm::IndexedInstrProfReader *getPGOReader() const { return PGOReader.get(); }