Add hybrid assembler concept to ARM assembler.

src/IceAssembler.cpp

 //===- subzero/src/IceAssembler.cpp - Assembler base class ----------------===//
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // Modified by the Subzero authors.
 //
 // This is forked from Dart revision 39313.
 // Please update the revision if we merge back changes from Dart.
 // https://code.google.com/p/dart/wiki/GettingTheSource
@@ skipping 17 matching lines @@
 #include "IceGlobalContext.h"
 #include "IceOperand.h"
 
 namespace Ice {
 
 static uintptr_t NewContents(Assembler &Assemblr, intptr_t Capacity) {
   uintptr_t Result = Assemblr.allocateBytes(Capacity);
   return Result;
 }
 
+void AssemblerBuffer::installFixup(AssemblerFixup *F) {
+  F->set_position(0);
+  if (!Assemblr.getPreliminary())
+    Fixups.push_back(F);
+}
+
 AssemblerFixup *AssemblerBuffer::createFixup(FixupKind Kind,
                                              const Constant *Value) {
   AssemblerFixup *F =
       new (Assemblr.allocate<AssemblerFixup>()) AssemblerFixup();
-  F->set_position(0);
   F->set_kind(Kind);
   F->set_value(Value);
-  if (!Assemblr.getPreliminary())
-    Fixups.push_back(F);
+  installFixup(F);
   return F;
 }
 
+AssemblerTextFixup *AssemblerBuffer::createTextFixup(const std::string &Text,
+                                                     size_t BytesUsed) {
+  AssemblerTextFixup *F = new (Assemblr.allocate<AssemblerTextFixup>())
+      AssemblerTextFixup(Text, BytesUsed);
+  installFixup(F);
+  TextFixupNeeded = false;
+  return F;
+}
+
 void AssemblerBuffer::EnsureCapacity::validate(AssemblerBuffer *buffer) {
   // In debug mode, we save the assembler buffer along with the gap size before
   // we start emitting to the buffer. This allows us to check that any single
   // generated instruction doesn't overflow the limit implied by the minimum
   // gap size.
   Gap = computeGap();
   // Make sure that extending the capacity leaves a big enough gap for any kind
   // of instruction.
   assert(Gap >= kMinimumGap);
   // Mark the buffer as having ensured the capacity.
   assert(!buffer->hasEnsuredCapacity()); // Cannot nest.
   buffer->HasEnsuredCapacity = true;
 }
 
 AssemblerBuffer::EnsureCapacity::~EnsureCapacity() {
   // Unmark the buffer, so we cannot emit after this.
   Buffer->HasEnsuredCapacity = false;
   // Make sure the generated instruction doesn't take up more space than the
   // minimum gap.
   intptr_t delta = Gap - computeGap();
   (void)delta;
   assert(delta <= kMinimumGap);
 }
 
 AssemblerBuffer::AssemblerBuffer(Assembler &Asm) : Assemblr(Asm) {
-  const intptr_t OneKB = 1024;
-  static const intptr_t kInitialBufferCapacity = 4 * OneKB;
+  constexpr intptr_t OneKB = 1024;
+  static constexpr intptr_t kInitialBufferCapacity = 4 * OneKB;
   Contents = NewContents(Assemblr, kInitialBufferCapacity);
   Cursor = Contents;
   Limit = computeLimit(Contents, kInitialBufferCapacity);
   HasEnsuredCapacity = false;
+  TextFixupNeeded = false;
 
   // Verify internal state.
   assert(capacity() == kInitialBufferCapacity);
   assert(size() == 0);
 }
 
 AssemblerBuffer::~AssemblerBuffer() = default;
 
 void AssemblerBuffer::extendCapacity() {
   intptr_t old_size = size();
   intptr_t old_capacity = capacity();
-  const intptr_t OneMB = 1 << 20;
+  constexpr intptr_t OneMB = 1 << 20;
   intptr_t new_capacity = std::min(old_capacity * 2, old_capacity + OneMB);
   if (new_capacity < old_capacity) {
     llvm::report_fatal_error(
         "Unexpected overflow in AssemblerBuffer::ExtendCapacity");
   }
 
   // Allocate the new data area and copy contents of the old one to it.
   uintptr_t new_contents = NewContents(Assemblr, new_capacity);
   memmove(reinterpret_cast<void *>(new_contents),
           reinterpret_cast<void *>(Contents), old_size);
@@ skipping 13 matching lines @@
 
 llvm::StringRef Assembler::getBufferView() const {
   return llvm::StringRef(reinterpret_cast<const char *>(Buffer.contents()),
                          Buffer.size());
 }
 
 void Assembler::emitIASBytes() const {
   Ostream &Str = Ctx->getStrEmit();
   intptr_t EndPosition = Buffer.size();
   intptr_t CurPosition = 0;
-  const intptr_t FixupSize = 4;
   for (const AssemblerFixup *NextFixup : fixups()) {
     intptr_t NextFixupLoc = NextFixup->position();
     for (intptr_t i = CurPosition; i < NextFixupLoc; ++i) {
       Str << "\t.byte 0x";
       Str.write_hex(Buffer.load<uint8_t>(i));
       Str << "\n";
     }
-    Str << "\t.long ";
     // For PCRel fixups, we write the pc-offset from a symbol into the Buffer
     // (e.g., -4), but we don't represent that in the fixup's offset. Otherwise
     // the fixup holds the true offset, and so does the Buffer. Just load the
     // offset from the buffer.
-    NextFixup->emit(Ctx, Buffer.load<RelocOffsetT>(NextFixupLoc));
-    if (fixupIsPCRel(NextFixup->kind()))
-      Str << " - .";
-    Str << "\n";
-    CurPosition = NextFixupLoc + FixupSize;
+    CurPosition = NextFixupLoc +
+                  NextFixup->emit(Ctx, Buffer.load<RelocOffsetT>(NextFixupLoc),
+                                  fixupIsPCRel(NextFixup->kind()));
     assert(CurPosition <= EndPosition);
   }
   // Handle any bytes that are not prefixed by a fixup.
   for (intptr_t i = CurPosition; i < EndPosition; ++i) {
     Str << "\t.byte 0x";
     Str.write_hex(Buffer.load<uint8_t>(i));
     Str << "\n";
   }
 }
 
 } // end of namespace Ice