Implememting named register intrinsics

This patch implements the infrastructure to use named register constructs in
programs that need access to specific registers (bare metal, kernels, etc).

So far, only the stack pointer is supported as a technology preview, but as it
is, the intrinsic can already support all non-allocatable registers from any
architecture.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208104 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/Target/AArch64/AArch64ISelLowering.cpp b/lib/Target/AArch64/AArch64ISelLowering.cpp
index 5ad2036d51..a016e6e485 100644
--- a/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -15,6 +15,7 @@
 #include "AArch64.h"
 #include "AArch64ISelLowering.h"
 #include "AArch64MachineFunctionInfo.h"
+#include "AArch64Subtarget.h"
 #include "AArch64TargetMachine.h"
 #include "AArch64TargetObjectFile.h"
 #include "Utils/AArch64BaseInfo.h"
@@ -2406,6 +2407,17 @@ SDValue AArch64TargetLowering::LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG)
   return FrameAddr;
 }
 
+// FIXME? Maybe this could be a TableGen attribute on some registers and
+// this table could be generated automatically from RegInfo.
+unsigned AArch64TargetLowering::getRegisterByName(const char* RegName) const {
+  unsigned Reg = StringSwitch<unsigned>(RegName)
+                       .Case("sp", AArch64::XSP)
+                       .Default(0);
+  if (Reg)
+    return Reg;
+  report_fatal_error("Invalid register name global variable");
+}
+
 SDValue
 AArch64TargetLowering::LowerGlobalAddressELFLarge(SDValue Op,
                                                   SelectionDAG &DAG) const {