Add hybrid assembler concept to ARM assembler.

src/IceFixups.h

Index: src/IceFixups.h
diff --git a/src/IceFixups.h b/src/IceFixups.h
index 43284ac9fefb8b3f81fc40c35ec0e6d7c1eb3e0f..bad27cf402cc892f848a16cc8ca1d1ceb0bd8621 100644
--- a/src/IceFixups.h
+++ b/src/IceFixups.h
@@ -45,7 +45,9 @@ public:
 
   void set_value(const Constant *Value) { value_ = Value; }
 
-  void emit(GlobalContext *Ctx, RelocOffsetT OverrideOffset) const;
+  // Emits fixup, then returns the number of bytes to skip.

[Jim Stichnoth, 2015/10/21 01:13:38]

Use /// doxygen style comment?

[Karl, 2015/10/22 15:20:53]

Done.

+  virtual size_t emit(GlobalContext *Ctx, RelocOffsetT OverrideOffset,
+                      bool IsPCRel) const;
 
 private:
   intptr_t position_ = 0;
@@ -53,6 +55,22 @@ private:
   const Constant *value_ = nullptr;
 };
 
+/// Extends a fixup to be a textual. That is, it emits text instead of a

[Jim Stichnoth, 2015/10/21 01:13:38]

I would say s/to be a/to be/ .

[Karl, 2015/10/22 15:20:53]

Done.

+/// sequence of bytes. This class is used to implement unimplemented emitIAS

[Jim Stichnoth, 2015/10/21 01:13:38]

maybe "as a fallback for" instead of "to implement"

[Karl, 2015/10/22 15:20:53]

Done.

+/// methods, allowing them to generate compilable assembly code.
+class AssemblerTextFixup : public AssemblerFixup {

[Jim Stichnoth, 2015/10/21 01:13:38]

Delete default copy ctor, assignment operator, etc.

[Karl, 2015/10/22 15:20:53]

Done.

+public:
+  AssemblerTextFixup(const std::string &Message, size_t NumBytes)
+      : AssemblerFixup(), Message(Message), NumBytes(NumBytes) {}
+  ~AssemblerTextFixup() = default;
+  virtual size_t emit(GlobalContext *Ctx, RelocOffsetT OverrideOffset,
+                      bool isPcRel) const;
+
+private:
+  const std::string Message;
+  const size_t NumBytes;
+};
+
 using FixupList = std::vector<AssemblerFixup>;
 using FixupRefList = std::vector<AssemblerFixup *>;