Disentangle assembler from isolate.

src/ppc/assembler-ppc.h

Index: src/ppc/assembler-ppc.h
diff --git a/src/ppc/assembler-ppc.h b/src/ppc/assembler-ppc.h
index 24119a27505819493889cf3626d85b3e1a206902..dde441e8439decf9c521d05eeecbcbc0ed929af8 100644
--- a/src/ppc/assembler-ppc.h
+++ b/src/ppc/assembler-ppc.h
@@ -397,7 +397,9 @@ class Assembler : public AssemblerBase {
   // for code generation and assumes its size to be buffer_size. If the buffer
   // is too small, a fatal error occurs. No deallocation of the buffer is done
   // upon destruction of the assembler.
-  Assembler(Isolate* isolate, void* buffer, int buffer_size);
+  Assembler(Isolate* isolate, void* buffer, int buffer_size)
+      : Assembler(IsolateData(isolate), buffer, buffer_size) {}
+  Assembler(IsolateData isolate_data, void* buffer, int buffer_size);
   virtual ~Assembler() {}
 
   // GetCode emits any pending (non-emitted) code and fills the descriptor
@@ -462,6 +464,7 @@ class Assembler : public AssemblerBase {
       ConstantPoolEntry::Type type));
 
   // Read/Modify the code target address in the branch/call instruction at pc.
+  // The isolate argument is unused (and may be nullptr) when skipping flushing.
   INLINE(static Address target_address_at(Address pc, Address constant_pool));
   INLINE(static void set_target_address_at(
       Isolate* isolate, Address pc, Address constant_pool, Address target,
@@ -1369,7 +1372,6 @@ class Assembler : public AssemblerBase {
 
   bool is_trampoline_emitted() const { return trampoline_emitted_; }
 
- private:
   // Code generation
   // The relocation writer's position is at least kGap bytes below the end of
   // the generated instructions. This is so that multi-instruction sequences do
@@ -1377,6 +1379,9 @@ class Assembler : public AssemblerBase {
   // relocation info entries.
   static constexpr int kGap = 32;
 
+  RelocInfoWriter reloc_info_writer;
+
+ private:
   // Repeated checking whether the trampoline pool should be emitted is rather
   // expensive. By default we only check again once a number of instructions
   // has been generated.
@@ -1392,7 +1397,6 @@ class Assembler : public AssemblerBase {
   // Relocation info generation
   // Each relocation is encoded as a variable size value
   static constexpr int kMaxRelocSize = RelocInfoWriter::kMaxSize;
-  RelocInfoWriter reloc_info_writer;
   std::vector<DeferredRelocInfo> relocations_;
 
   // The bound position, before this we cannot do instruction elimination.
@@ -1489,6 +1493,15 @@ class EnsureSpace BASE_EMBEDDED {
  public:
   explicit EnsureSpace(Assembler* assembler) { assembler->CheckBuffer(); }
 };
+
+class PatchingAssembler : public Assembler {
+ public:
+  PatchingAssembler(IsolateData isolate_data, byte* address, int instructions);
+  ~PatchingAssembler();
+
+  void FlushICache(Isolate* isolate);
+};
+
 }  // namespace internal
 }  // namespace v8