Contribution of PowerPC port.

src/disassembler.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/code-stubs.h"
 #include "src/codegen.h"
 #include "src/debug.h"
 #include "src/deoptimizer.h"
@@ skipping 89 matching lines @@
   v8::internal::EmbeddedVector<char, kOutBufferSize> out_buffer;
   StringBuilder out(out_buffer.start(), out_buffer.length());
   byte* pc = begin;
   disasm::Disassembler d(converter);
   RelocIterator* it = NULL;
   if (converter.code() != NULL) {
     it = new RelocIterator(converter.code());
   } else {
     // No relocation information when printing code stubs.
   }
+#if !V8_TARGET_ARCH_PPC
   int constants = -1;  // no constants being decoded at the start
+#endif
 
   while (pc < end) {
     // First decode instruction so that we know its length.
     byte* prev_pc = pc;
+#if !V8_TARGET_ARCH_PPC
     if (constants > 0) {
       SNPrintF(decode_buffer,
                "%08x       constant",
                *reinterpret_cast<int32_t*>(pc));
       constants--;
       pc += 4;
     } else {
       int num_const = d.ConstantPoolSizeAt(pc);
       if (num_const >= 0) {
         SNPrintF(decode_buffer,
                  "%08x       constant pool begin",
                  *reinterpret_cast<int32_t*>(pc));
         constants = num_const;
         pc += 4;
       } else if (it != NULL && !it->done() && it->rinfo()->pc() == pc &&
           it->rinfo()->rmode() == RelocInfo::INTERNAL_REFERENCE) {
         // raw pointer embedded in code stream, e.g., jump table
         byte* ptr = *reinterpret_cast<byte**>(pc);
         SNPrintF(decode_buffer,
                  "%08" V8PRIxPTR "      jump table entry %4" V8PRIdPTR,
                  reinterpret_cast<intptr_t>(ptr),
                  ptr - begin);
         pc += 4;
       } else {
+#elif ABI_USES_FUNCTION_DESCRIPTORS || V8_OOL_CONSTANT_POOL
+    // V8_TARGET_ARCH_PPC
+    {
+      // Function descriptors are specially decoded and skipped.
+      // Other internal references (load of ool constant pool pointer)
+      // are not since they are a encoded as a regular mov sequence.
+      int skip;
+      if (it != NULL && !it->done() && it->rinfo()->pc() == pc &&

[danno, 2014/07/29 13:24:08]

Again, please try to avoid non-boilerplate platform #ifdefs in shared code
whenever possible.

It seems like it would be cleaner to make everything in this if() a call to a
help function that is present on all platforms that also returns "false" on non
PPC (and thus falls through to the decode_buffer[...] code), and actually does
this heavy lifting on PPC.

[andrew_low, 2014/07/30 13:27:04]

I'm going to need a bit more help / detail here. Your comment appears to be
attached to line 149 in my modified version of the file. However, if we look
back on line 117 we can see #if !V8_TARGET_ARCH_PPC which seems like a bad idea.

I don't dis-agree with the idea of refactoring this. When developing the code,
we avoided changing the other sub-directories (implementations) and this caused
a bit more of a mess in common code.

Please be more specific in your refactoring / abstraction suggestion.

On 2014/07/29 13:24:08, danno wrote:

+          it->rinfo()->rmode() == RelocInfo::INTERNAL_REFERENCE &&
+          (skip = Assembler::DecodeInternalReference(decode_buffer, pc))) {
+        pc += skip;
+      } else {
+#else
+    {
+      {
+#endif
         decode_buffer[0] = '\0';
         pc += d.InstructionDecode(decode_buffer, pc);
       }
     }
 
     // Collect RelocInfo for this instruction (prev_pc .. pc-1)
     List<const char*> comments(4);
     List<byte*> pcs(1);
     List<RelocInfo::Mode> rmodes(1);
     List<intptr_t> datas(1);
@@ skipping 177 matching lines @@
 int Disassembler::Decode(Isolate* isolate, FILE* f, byte* begin, byte* end) {
   return 0;
 }
 
 
 void Disassembler::Decode(FILE* f, Code* code) {}
 
 #endif  // ENABLE_DISASSEMBLER
 
 } }  // namespace v8::internal