Swift Calling Convention: add swifterror attribute.

A ``swifterror`` attribute can be applied to a function parameter or an
AllocaInst.

This commit does not include any target-specific change. The target-specific
optimization will come as a follow-up patch.

Differential Revision: http://reviews.llvm.org/D18092

llvm-svn: 265189

1 files changed, 7 insertions, 3 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 1840b60cc01..45435962a7c 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1317,6 +1317,8 @@ static Attribute::AttrKind getAttrFromCode(uint64_t Code) {
     return Attribute::SanitizeThread;
   case bitc::ATTR_KIND_SANITIZE_MEMORY:
     return Attribute::SanitizeMemory;
+  case bitc::ATTR_KIND_SWIFT_ERROR:
+    return Attribute::SwiftError;
   case bitc::ATTR_KIND_SWIFT_SELF:
     return Attribute::SwiftSelf;
   case bitc::ATTR_KIND_UW_TABLE:
@@ -4843,10 +4845,11 @@ std::error_code BitcodeReader::parseFunctionBody(Function *F) {
       uint64_t AlignRecord = Record[3];
       const uint64_t InAllocaMask = uint64_t(1) << 5;
       const uint64_t ExplicitTypeMask = uint64_t(1) << 6;
-      // Reserve bit 7 for SwiftError flag.
-      // const uint64_t SwiftErrorMask = uint64_t(1) << 7;
-      const uint64_t FlagMask = InAllocaMask | ExplicitTypeMask;
+      const uint64_t SwiftErrorMask = uint64_t(1) << 7;
+      const uint64_t FlagMask = InAllocaMask | ExplicitTypeMask |
+                                SwiftErrorMask;
       bool InAlloca = AlignRecord & InAllocaMask;
+      bool SwiftError = AlignRecord & SwiftErrorMask;
       Type *Ty = getTypeByID(Record[0]);
       if ((AlignRecord & ExplicitTypeMask) == 0) {
         auto *PTy = dyn_cast_or_null<PointerType>(Ty);
@@ -4865,6 +4868,7 @@ std::error_code BitcodeReader::parseFunctionBody(Function *F) {
         return error("Invalid record");
       AllocaInst *AI = new AllocaInst(Ty, Size, Align);
       AI->setUsedWithInAlloca(InAlloca);
+      AI->setSwiftError(SwiftError);
       I = AI;
       InstructionList.push_back(I);
       break;