Handle ARM "ret void" and function alignment with proper padding.

src/IceInstARM32.cpp

+//===- subzero/src/IceInstARM32.cpp - ARM32 instruction implementation ----===//
+//
+//                        The Subzero Code Generator
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the InstARM32 and OperandARM32 classes,
+// primarily the constructors and the dump()/emit() methods.
+//
+//===----------------------------------------------------------------------===//
+
+#include "assembler_arm32.h"
+#include "IceCfg.h"
+#include "IceCfgNode.h"
+#include "IceInst.h"
+#include "IceInstARM32.h"
+#include "IceRegistersARM32.h"
+#include "IceTargetLoweringARM32.h"
+#include "IceOperand.h"

[Jim Stichnoth, 2015/05/11 20:12:31]

sort includes

[jvoung (off chromium), 2015/05/11 22:11:51]

Done.

+
+namespace Ice {
+
+namespace {
+
+const struct TypeARM32Attributes_ {
+  const char *WidthString; // b, h, <blank>, or d
+} TypeARM32Attributes[] = {
+#define X(tag, elementty, width)                                               \
+  { width }                                                                    \
+  ,
+    ICETYPEARM32_TABLE
+#undef X
+};
+
+} // end of anonymous namespace
+
+const char *InstARM32::getWidthString(Type Ty) {
+  return TypeARM32Attributes[Ty].WidthString;
+}
+
+InstARM32Ret::InstARM32Ret(Cfg *Func, Variable *LR, Variable *Source)
+    : InstARM32(Func, InstARM32::Ret, Source ? 2 : 1, nullptr) {
+  addSource(LR);
+  if (Source)
+    addSource(Source);
+}
+
+// ======================== Dump routines ======================== //
+
+void InstARM32::dump(const Cfg *Func) const {
+  if (!ALLOW_DUMP)
+    return;
+  Ostream &Str = Func->getContext()->getStrDump();
+  Str << "[ARM32] ";
+  Inst::dump(Func);
+}
+
+void InstARM32Ret::emit(const Cfg *Func) const {
+  if (!ALLOW_DUMP)
+    return;
+  assert(getSrcSize() > 0);
+  Variable *LR = llvm::cast<Variable>(getSrc(0));
+  assert(LR->hasReg() && LR->getRegNum() == RegARM32::Reg_lr);

[Jim Stichnoth, 2015/05/11 20:12:31]

Break into 2 asserts?  makes it easier to debug an assertion failure

[jvoung (off chromium), 2015/05/11 22:11:50]

Done.

+  Ostream &Str = Func->getContext()->getStrEmit();
+  Str << "\tbx\t";

[Jim Stichnoth, 2015/05/11 20:12:31]

Just to share an idle thought -- I was thinking of changing lines like this to
something like:
  Str << TABSTR << "bx" << TABSTR;
which would make it easier to "git grep -w" on these strings.

[jvoung (off chromium), 2015/05/11 22:11:51]

Hmm yeah that sounds good.

+  LR->emit(Func);
+}
+
+void InstARM32Ret::emitIAS(const Cfg *Func) const {
+  (void)Func;
+  llvm_unreachable("Not yet implemented");
+}
+
+void InstARM32Ret::dump(const Cfg *Func) const {
+  if (!ALLOW_DUMP)
+    return;
+  Ostream &Str = Func->getContext()->getStrDump();
+  Type Ty = (getSrcSize() == 1 ? IceType_void : getSrc(0)->getType());
+  Str << "ret." << Ty << " ";
+  dumpSources(Func);
+}
+
+} // end of namespace Ice