LLDB JIT needs android vector passing rules.

Summary:
Looking into some recent issues with LLDBs expression parser highlighted that upstream clang passes vectors types differently to Android Open Source Project's clang for Arm Android targets.
This patch reflects the changes present in the AOSP and allows LLDB's JIT expression evaluation to work correctly for Arm Android targets when passing vectors.

This is submitted with consent of the original author Stephen Hines.

Reviewers: asl, rsmith, ADodds, rnk

Subscribers: rnk, aemerson, tberghammer, danalbert, srhines, cfe-commits, pirama

Differential Revision: http://reviews.llvm.org/D14639

llvm-svn: 254682

1 files changed, 26 insertions, 9 deletions

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index da262c1087c..290a0755d63 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -4730,6 +4730,11 @@ public:
     }
   }
 
+  bool isAndroid() const {
+    return (getTarget().getTriple().getEnvironment() ==
+            llvm::Triple::Android);
+  }
+
   ABIKind getABIKind() const { return Kind; }
 
 private:
@@ -5233,15 +5238,27 @@ ABIArgInfo ARMABIInfo::classifyReturnType(QualType RetTy,
 
 /// isIllegalVector - check whether Ty is an illegal vector type.
 bool ARMABIInfo::isIllegalVectorType(QualType Ty) const {
-  if (const VectorType *VT = Ty->getAs<VectorType>()) {
-    // Check whether VT is legal.
-    unsigned NumElements = VT->getNumElements();
-    uint64_t Size = getContext().getTypeSize(VT);
-    // NumElements should be power of 2.
-    if ((NumElements & (NumElements - 1)) != 0)
-      return true;
-    // Size should be greater than 32 bits.
-    return Size <= 32;
+  if (const VectorType *VT = Ty->getAs<VectorType> ()) {
+    if (isAndroid()) {
+      // Android shipped using Clang 3.1, which supported a slightly different
+      // vector ABI. The primary differences were that 3-element vector types
+      // were legal, and so were sub 32-bit vectors (i.e. <2 x i8>). This path
+      // accepts that legacy behavior for Android only.
+      // Check whether VT is legal.
+      unsigned NumElements = VT->getNumElements();
+      // NumElements should be power of 2 or equal to 3.
+      if (!llvm::isPowerOf2_32(NumElements) && NumElements != 3)
+        return true;
+    } else {
+      // Check whether VT is legal.
+      unsigned NumElements = VT->getNumElements();
+      uint64_t Size = getContext().getTypeSize(VT);
+      // NumElements should be power of 2.
+      if (!llvm::isPowerOf2_32(NumElements))
+        return true;
+      // Size should be greater than 32 bits.
+      return Size <= 32;
+    }
   }
   return false;
 }