ARM: Assign "actuals" at call site to the appropriate GPR/stack slot.

src/IceInstARM32.h

Index: src/IceInstARM32.h
diff --git a/src/IceInstARM32.h b/src/IceInstARM32.h
index 1ba5d4e9efd5a5a14adb96a811026193ffed8aba..b9ed01e36e40b25cd1df093e161f61694b284325 100644
--- a/src/IceInstARM32.h
+++ b/src/IceInstARM32.h
@@ -258,6 +258,7 @@ public:
     k__Start = Inst::Target,
     Adc,
     Add,
+    Adjuststack,
     And,
     Asr,
     Bic,
@@ -606,6 +607,34 @@ private:
   const CfgNode *TargetFalse;
 };
 
+// AdjustStack instruction - subtracts SP by the given amount and
+// updates the stack offset during code emission.
+class InstARM32AdjustStack : public InstARM32 {
+  InstARM32AdjustStack() = delete;
+  InstARM32AdjustStack(const InstARM32AdjustStack &) = delete;
+  InstARM32AdjustStack &operator=(const InstARM32AdjustStack &) = delete;
+
+public:
+  // Note: We need both Amount and SrcAmount. If Amount is too large then
+  // it needs to be copied to a register (so SrcAmount could be a register).
+  // However, we also need the numeric Amount for bookkeeping, and it's
+  // hard to pull that from the generic SrcAmount operand.
+  static InstARM32AdjustStack *create(Cfg *Func, Variable *SP, SizeT Amount,
+                                      Operand *SrcAmount) {
+    return new (Func->allocate<InstARM32AdjustStack>())
+        InstARM32AdjustStack(Func, SP, Amount, SrcAmount);
+  }
+  void emit(const Cfg *Func) const override;
+  void emitIAS(const Cfg *Func) const override;
+  void dump(const Cfg *Func) const override;
+  static bool classof(const Inst *Inst) { return isClassof(Inst, Adjuststack); }
+
+private:
+  InstARM32AdjustStack(Cfg *Func, Variable *SP, SizeT Amount,
+                       Operand *SrcAmount);
+  const SizeT Amount;
+};
+
 // Call instruction (bl/blx).  Arguments should have already been pushed.
 // Technically bl and the register form of blx can be predicated, but we'll
 // leave that out until needed.