diff --git a/lib/CodeGen/TargetInfo.cpp b/lib/CodeGen/TargetInfo.cpp
index cb5c672..563ca5c 100644
--- a/lib/CodeGen/TargetInfo.cpp
+++ b/lib/CodeGen/TargetInfo.cpp
@@ -87,6 +87,17 @@
 
 TargetCodeGenInfo::~TargetCodeGenInfo() { delete Info; }
 
+// If someone can figure out a general rule for this, that would be great.
+// It's probably just doomed to be platform-dependent, though.
+unsigned TargetCodeGenInfo::getSizeOfUnwindException() const {
+  // Verified for:
+  //   x86-64     FreeBSD, Linux, Darwin
+  //   x86-32     FreeBSD, Linux, Darwin
+  //   PowerPC    Linux, Darwin
+  //   ARM        Darwin (*not* EABI)
+  return 32;
+}
+
 static bool isEmptyRecord(ASTContext &Context, QualType T, bool AllowArrays);
 
 /// isEmptyField - Return true iff a the field is "empty", that is it
@@ -2300,6 +2311,11 @@
 public:
   ARMABIInfo(CodeGenTypes &CGT, ABIKind _Kind) : ABIInfo(CGT), Kind(_Kind) {}
 
+  bool isEABI() const {
+    StringRef Env = getContext().Target.getTriple().getEnvironmentName();
+    return (Env == "gnueabi" || Env == "eabi");
+  }
+
 private:
   ABIKind getABIKind() const { return Kind; }
 
@@ -2317,6 +2333,10 @@
   ARMTargetCodeGenInfo(CodeGenTypes &CGT, ARMABIInfo::ABIKind K)
     :TargetCodeGenInfo(new ARMABIInfo(CGT, K)) {}
 
+  const ARMABIInfo &getABIInfo() const {
+    return static_cast<const ARMABIInfo&>(TargetCodeGenInfo::getABIInfo());
+  }
+
   int getDwarfEHStackPointer(CodeGen::CodeGenModule &M) const {
     return 13;
   }
@@ -2338,6 +2358,11 @@
 
     return false;
   }
+
+  unsigned getSizeOfUnwindException() const {
+    if (getABIInfo().isEABI()) return 88;
+    return TargetCodeGenInfo::getSizeOfUnwindException();
+  }
 };
 
 }
@@ -2354,8 +2379,7 @@
 
   // Calling convention as default by an ABI.
   llvm::CallingConv::ID DefaultCC;
-  StringRef Env = getContext().Target.getTriple().getEnvironmentName();
-  if (Env == "gnueabi" || Env == "eabi")
+  if (isEABI())
     DefaultCC = llvm::CallingConv::ARM_AAPCS;
   else
     DefaultCC = llvm::CallingConv::ARM_APCS;
@@ -3007,6 +3031,10 @@
 
   bool initDwarfEHRegSizeTable(CodeGen::CodeGenFunction &CGF,
                                llvm::Value *Address) const;
+
+  unsigned getSizeOfUnwindException() const {
+    return 24;
+  }
 };
 }
 
diff --git a/lib/CodeGen/TargetInfo.h b/lib/CodeGen/TargetInfo.h
index a188b9c..22e6eb8 100644
--- a/lib/CodeGen/TargetInfo.h
+++ b/lib/CodeGen/TargetInfo.h
@@ -59,7 +59,7 @@
     ///     uint64 private_1;
     ///     uint64 private_2;
     ///   };
-    unsigned getSizeOfUnwindException() const { return 32; }
+    virtual unsigned getSizeOfUnwindException() const;
 
     /// Controls whether __builtin_extend_pointer should sign-extend
     /// pointers to uint64_t or zero-extend them (the default).  Has
diff --git a/test/CodeGenCXX/sizeof-unwind-exception.cpp b/test/CodeGenCXX/sizeof-unwind-exception.cpp
new file mode 100644
index 0000000..5db4df7
--- /dev/null
+++ b/test/CodeGenCXX/sizeof-unwind-exception.cpp
@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fcxx-exceptions -fexceptions %s -O2 -o - | FileCheck %s --check-prefix=X86-64
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fcxx-exceptions -fexceptions %s -O2 -o - | FileCheck %s --check-prefix=X86-32
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fcxx-exceptions -fexceptions %s -O2 -o - | FileCheck %s --check-prefix=ARM-DARWIN
+// RUN: %clang_cc1 -triple arm-unknown-gnueabi -emit-llvm -fcxx-exceptions -fexceptions %s -O2 -o - | FileCheck %s --check-prefix=ARM-EABI
+// RUN: %clang_cc1 -triple mipsel-unknown-unknown -emit-llvm -fcxx-exceptions -fexceptions %s -O2 -o - | FileCheck %s --check-prefix=MIPS
+
+void foo();
+void test() {
+  try {
+    foo();
+  } catch (int *&i) {
+    *i = 5;
+  }
+}
+
+// PR10789: different platforms have different sizes for struct UnwindException.
+
+// X86-64:          [[T0:%.*]] = tail call i8* @__cxa_begin_catch(i8* [[EXN:%.*]]) nounwind
+// X86-64-NEXT:     [[T1:%.*]] = getelementptr i8* [[EXN]], i64 32
+// X86-32:          [[T0:%.*]] = tail call i8* @__cxa_begin_catch(i8* [[EXN:%.*]]) nounwind
+// X86-32-NEXT:     [[T1:%.*]] = getelementptr i8* [[EXN]], i64 32
+// ARM-DARWIN:      [[T0:%.*]] = tail call i8* @__cxa_begin_catch(i8* [[EXN:%.*]]) nounwind
+// ARM-DARWIN-NEXT: [[T1:%.*]] = getelementptr i8* [[EXN]], i64 32
+// ARM-EABI:        [[T0:%.*]] = tail call i8* @__cxa_begin_catch(i8* [[EXN:%.*]]) nounwind
+// ARM-EABI-NEXT:   [[T1:%.*]] = getelementptr i8* [[EXN]], i32 88
+// MIPS:            [[T0:%.*]] = tail call i8* @__cxa_begin_catch(i8* [[EXN:%.*]]) nounwind
+// MIPS-NEXT:       [[T1:%.*]] = getelementptr i8* [[EXN]], i32 24
+