Model :upper16: and :lower16: as ARM specific MCTargetExpr. This is a step

in the right direction. It eliminated some hacks and will unblock codegen
work. But it's far from being done. It doesn't reject illegal expressions,
e.g. (FOO - :lower16:BAR). It also doesn't work in Thumb2 mode at all.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123369 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 73 insertions, 0 deletions

diff --git a/lib/Target/ARM/ARMMCExpr.cpp b/lib/Target/ARM/ARMMCExpr.cpp
new file mode 100644
index 0000000000..2727ba8c8a
--- /dev/null
+++ b/lib/Target/ARM/ARMMCExpr.cpp
@@ -0,0 +1,73 @@
+//===-- ARMMCExpr.cpp - ARM specific MC expression classes ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "armmcexpr"
+#include "ARMMCExpr.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCAssembler.h"
+using namespace llvm;
+
+const ARMMCExpr*
+ARMMCExpr::Create(VariantKind Kind, const MCExpr *Expr,
+                       MCContext &Ctx) {
+  return new (Ctx) ARMMCExpr(Kind, Expr);
+}
+
+void ARMMCExpr::PrintImpl(raw_ostream &OS) const {
+  switch (Kind) {
+  default: assert(0 && "Invalid kind!");
+  case VK_ARM_HI16: OS << ":upper16:"; break;
+  case VK_ARM_LO16: OS << ":lower16:"; break;
+  }
+
+  const MCExpr *Expr = getSubExpr();
+  if (Expr->getKind() != MCExpr::SymbolRef)
+    OS << '(';
+  Expr->print(OS);
+  if (Expr->getKind() != MCExpr::SymbolRef)
+    OS << ')';
+}
+
+bool
+ARMMCExpr::EvaluateAsRelocatableImpl(MCValue &Res,
+                                     const MCAsmLayout *Layout) const {
+  return false;
+}
+
+// FIXME: This basically copies MCObjectStreamer::AddValueSymbols. Perhaps
+// that method should be made public?
+static void AddValueSymbols_(const MCExpr *Value, MCAssembler *Asm) {
+  switch (Value->getKind()) {
+  case MCExpr::Target:
+    assert(0 && "Can't handle nested target expr!");
+    break;
+
+  case MCExpr::Constant:
+    break;
+
+  case MCExpr::Binary: {
+    const MCBinaryExpr *BE = cast<MCBinaryExpr>(Value);
+    AddValueSymbols_(BE->getLHS(), Asm);
+    AddValueSymbols_(BE->getRHS(), Asm);
+    break;
+  }
+
+  case MCExpr::SymbolRef:
+    Asm->getOrCreateSymbolData(cast<MCSymbolRefExpr>(Value)->getSymbol());
+    break;
+
+  case MCExpr::Unary:
+    AddValueSymbols_(cast<MCUnaryExpr>(Value)->getSubExpr(), Asm);
+    break;
+  }
+}
+
+void ARMMCExpr::AddValueSymbols(MCAssembler *Asm) const {
+  AddValueSymbols_(getSubExpr(), Asm);
+}