[AArch64] Add __builtin_sponentry, for calling setjmp in MinGW

[mstorsjo]

Summary

In MinGW, setjmp isn't expanded as a builtin in the compiler (like it is for MSVC), but manually hooked up as calls to the right underlying functions in headers. Using the actual CRT's real setjmp/longjmp functions requires this intrinsic. (Currently this is worked around by using MinGW specific reimplementations of setjmp/longjmp on aarch64.)

[rnk]

lgtm

include/clang/Basic/BuiltinsAArch64.def

 LANGBUILTIN(__dsb, "vUi", "nc", ALL_MS_LANGUAGES)
 LANGBUILTIN(__isb, "vUi", "nc", ALL_MS_LANGUAGES)
 LANGBUILTIN(__yield, "v", "",   ALL_MS_LANGUAGES)
 LANGBUILTIN(__wfe,   "v", "",   ALL_MS_LANGUAGES)
 LANGBUILTIN(__wfi,   "v", "",   ALL_MS_LANGUAGES)
 LANGBUILTIN(__sev,   "v", "",   ALL_MS_LANGUAGES)
 LANGBUILTIN(__sevl,  "v", "",   ALL_MS_LANGUAGES)
 
+// Misc
+BUILTIN(__builtin_sponentry, "v*", "c")
+
 TARGET_HEADER_BUILTIN(_BitScanForward, "UcUNi*UNi", "nh", "intrin.h", ALL_MS_LANGUAGES, "")
 TARGET_HEADER_BUILTIN(_BitScanReverse, "UcUNi*UNi", "nh", "intrin.h", ALL_MS_LANGUAGES, "")
 TARGET_HEADER_BUILTIN(_BitScanForward64, "UcUNi*ULLi", "nh", "intrin.h", ALL_MS_LANGUAGES, "")
 TARGET_HEADER_BUILTIN(_BitScanReverse64, "UcUNi*ULLi", "nh", "intrin.h", ALL_MS_LANGUAGES, "")
 
 TARGET_HEADER_BUILTIN(_InterlockedAdd,           "LiLiD*Li",    "nh", "intrin.h", ALL_MS_LANGUAGES, "")
 TARGET_HEADER_BUILTIN(_InterlockedAnd64,         "LLiLLiD*LLi", "nh", "intrin.h", ALL_MS_LANGUAGES, "")
 TARGET_HEADER_BUILTIN(_InterlockedDecrement64,   "LLiLLiD*",    "nh", "intrin.h", ALL_MS_LANGUAGES, "")

lib/CodeGen/CGBuiltin.cpp

if (BuiltinID == AArch64::BI_ReadStatusReg ||
     return Builder.CreateCall(F, { Metadata, ArgValue });
   }
 
   if (BuiltinID == AArch64::BI_AddressOfReturnAddress) {
     llvm::Function *F = CGM.getIntrinsic(Intrinsic::addressofreturnaddress);
     return Builder.CreateCall(F);
   }
 
+  if (BuiltinID == AArch64::BI__builtin_sponentry) {
+    llvm::Function *F = CGM.getIntrinsic(Intrinsic::sponentry);
+    return Builder.CreateCall(F);
+  }
+
   // Find out if any arguments are required to be integer constant
   // expressions.
   unsigned ICEArguments = 0;
   ASTContext::GetBuiltinTypeError Error;
   getContext().GetBuiltinType(BuiltinID, Error, &ICEArguments);
   assert(Error == ASTContext::GE_None && "Should not codegen an error");
 
   llvm::SmallVector<Value*, 4> Ops;

test/CodeGen/builtin-sponentry.c

+// RUN: %clang_cc1 -triple aarch64-windows-gnu -Oz -emit-llvm %s -o - | FileCheck %s
+
+void *test_sponentry() {
+  return __builtin_sponentry();
+}
+// CHECK-LABEL: define dso_local i8* @test_sponentry()
+// CHECK: = tail call i8* @llvm.sponentry()
+// CHECK: ret i8*