Enable gdb-jit for PPC64 on Linux (both big-endian and little-endian).

src/gdb-jit.cc

 // Copyright 2010 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/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/bootstrapper.h"
 #include "src/compiler.h"
@@ skipping 375 matching lines @@
                        uintptr_t addr,
                        uintptr_t offset,
                        uintptr_t size,
                        uintptr_t flags)
       : ELFSection(name, type, align),
         addr_(addr),
         offset_(offset),
         size_(size),
         flags_(flags) { }
 
+

[Jakob Kummerow, 2015/08/03 16:03:36]

nit: why this change?

  protected:
   virtual void PopulateHeader(Writer::Slot<Header> header) {
     ELFSection::PopulateHeader(header);
     header->address = addr_;
     header->offset = offset_;
     header->size = size_;
     header->flags = flags_;
   }
 
  private:
@@ skipping 236 matching lines @@
   };
 
 
   void WriteHeader(Writer* w) {
     DCHECK(w->position() == 0);
     Writer::Slot<ELFHeader> header = w->CreateSlotHere<ELFHeader>();
 #if (V8_TARGET_ARCH_IA32 || V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_X87 || \
      (V8_TARGET_ARCH_X64 && V8_TARGET_ARCH_32_BIT))
     const uint8_t ident[16] =
         { 0x7f, 'E', 'L', 'F', 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0};
-#elif V8_TARGET_ARCH_X64 && V8_TARGET_ARCH_64_BIT
+#elif(V8_TARGET_ARCH_X64 && V8_TARGET_ARCH_64_BIT) || \
+    (V8_TARGET_ARCH_PPC64 && V8_TARGET_LITTLE_ENDIAN)
     const uint8_t ident[16] =
         { 0x7f, 'E', 'L', 'F', 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+#elif V8_TARGET_ARCH_PPC64 && V8_TARGET_BIG_ENDIAN && V8_OS_LINUX
+    const uint8_t ident[16] = {0x7f, 'E', 'L', 'F', 2, 2, 1, 0,
+                               0,    0,   0,   0,   0, 0, 0, 0};
 #else
 #error Unsupported target architecture.
 #endif
     memcpy(header->ident, ident, 16);
     header->type = 1;
 #if V8_TARGET_ARCH_IA32 || V8_TARGET_ARCH_X87
     header->machine = 3;
 #elif V8_TARGET_ARCH_X64
     // Processor identification value for x64 is 62 as defined in
     //    System V ABI, AMD64 Supplement
     //    http://www.x86-64.org/documentation/abi.pdf
     header->machine = 62;
 #elif V8_TARGET_ARCH_ARM
     // Set to EM_ARM, defined as 40, in "ARM ELF File Format" at
     // infocenter.arm.com/help/topic/com.arm.doc.dui0101a/DUI0101A_Elf.pdf
     header->machine = 40;
+#elif V8_TARGET_ARCH_PPC64 && V8_OS_LINUX
+    // Set to EM_PPC64, defined as 21, in Power ABI,
+    // Join the next 4 lines, omitting the spaces and double-slashes.

[Jakob Kummerow, 2015/08/03 16:03:36]

Links are exempt from the 80-col policy; however this one is very long indeed,
and sticking wtih 80-col is nice. How about a goo.gl shortcut?

Or you can leave it as is, I'm fine with either.

+    // https://www-03.ibm.com/technologyconnect/tgcm/TGCMFileServlet.wss/
+    // ABI64BitOpenPOWERv1.1_16July2015_pub.pdf?
+    // id=B81AEC1A37F5DAF185257C3E004E8845&linkid=1n0000&c_t=
+    // c9xw7v5dzsj7gt1ifgf4cjbcnskqptmr
+    header->machine = 21;
 #else
 #error Unsupported target architecture.
 #endif
     header->version = 1;
     header->entry = 0;
     header->pht_offset = 0;
     header->sht_offset = sizeof(ELFHeader);  // Section table follows header.
     header->flags = 0;
     header->header_size = sizeof(ELFHeader);
     header->pht_entry_size = 0;
     header->pht_entry_num = 0;
     header->sht_entry_size = sizeof(ELFSection::Header);
     header->sht_entry_num = sections_.length();
     header->sht_strtab_index = 1;
   }
 
+

[Jakob Kummerow, 2015/08/03 16:03:36]

nit: why this change?

   void WriteSectionTable(Writer* w) {
     // Section headers table immediately follows file header.
     DCHECK(w->position() == sizeof(ELFHeader));
 
     Writer::Slot<ELFSection::Header> headers =
         w->CreateSlotsHere<ELFSection::Header>(sections_.length());
 
     // String table for section table is the first section.
     ELFStringTable* strtab = static_cast<ELFStringTable*>(SectionAt(1));
     strtab->AttachWriter(w);
@@ skipping 79 matching lines @@
           section(section) {
     }
 
     uint32_t name;
     uintptr_t value;
     uintptr_t size;
     uint8_t info;
     uint8_t other;
     uint16_t section;
   };
-#elif V8_TARGET_ARCH_X64 && V8_TARGET_ARCH_64_BIT
+#elif(V8_TARGET_ARCH_X64 && V8_TARGET_ARCH_64_BIT) || \
+    (V8_TARGET_ARCH_PPC64 && V8_OS_LINUX)
   struct SerializedLayout {
     SerializedLayout(uint32_t name,
                      uintptr_t value,
                      uintptr_t size,
                      Binding binding,
                      Type type,
                      uint16_t section)
         : name(name),
           info((binding << 4) | type),
           other(0),
@@ skipping 257 matching lines @@
   // DWARF2 standard
   enum DWARF2LocationOp {
     DW_OP_reg0 = 0x50,
     DW_OP_reg1 = 0x51,
     DW_OP_reg2 = 0x52,
     DW_OP_reg3 = 0x53,
     DW_OP_reg4 = 0x54,
     DW_OP_reg5 = 0x55,
     DW_OP_reg6 = 0x56,
     DW_OP_reg7 = 0x57,
+    DW_OP_reg8 = 0x58,
+    DW_OP_reg9 = 0x59,
+    DW_OP_reg10 = 0x5a,
+    DW_OP_reg11 = 0x5b,
+    DW_OP_reg12 = 0x5c,
+    DW_OP_reg13 = 0x5d,
+    DW_OP_reg14 = 0x5e,
+    DW_OP_reg15 = 0x5f,
+    DW_OP_reg16 = 0x60,
+    DW_OP_reg17 = 0x61,
+    DW_OP_reg18 = 0x62,
+    DW_OP_reg19 = 0x63,
+    DW_OP_reg20 = 0x64,
+    DW_OP_reg21 = 0x65,
+    DW_OP_reg22 = 0x66,
+    DW_OP_reg23 = 0x67,
+    DW_OP_reg24 = 0x68,
+    DW_OP_reg25 = 0x69,
+    DW_OP_reg26 = 0x6a,
+    DW_OP_reg27 = 0x6b,
+    DW_OP_reg28 = 0x6c,
+    DW_OP_reg29 = 0x6d,
+    DW_OP_reg30 = 0x6e,
+    DW_OP_reg31 = 0x6f,
     DW_OP_fbreg = 0x91  // 1 param: SLEB128 offset
   };
 
   enum DWARF2Encoding {
     DW_ATE_ADDRESS = 0x1,
     DW_ATE_SIGNED = 0x5
   };
 
   bool WriteBodyInternal(Writer* w) {
     uintptr_t cu_start = w->position();
@@ skipping 25 matching lines @@
 #if V8_TARGET_ARCH_IA32 || V8_TARGET_ARCH_X87
       w->Write<uint8_t>(DW_OP_reg5);  // The frame pointer's here on ia32
 #elif V8_TARGET_ARCH_X64
       w->Write<uint8_t>(DW_OP_reg6);  // and here on x64.
 #elif V8_TARGET_ARCH_ARM
       UNIMPLEMENTED();
 #elif V8_TARGET_ARCH_MIPS
       UNIMPLEMENTED();
 #elif V8_TARGET_ARCH_MIPS64
       UNIMPLEMENTED();
+#elif V8_TARGET_ARCH_PPC64 && V8_OS_LINUX
+      w->Write<uint8_t>(DW_OP_reg31);  // The frame pointer is here on PPC64

[Jakob Kummerow, 2015/08/03 16:03:36]

nit: trailing full stop please.

 #else
 #error Unsupported target architecture.
 #endif
       fb_block_size.set(static_cast<uint32_t>(w->position() - fb_block_start));
 
       int params = scope->ParameterCount();
       int slots = scope->StackLocalCount();
       int context_slots = scope->ContextLocalCount();
       // The real slot ID is internal_slots + context_slot_id.
       int internal_slots = Context::MIN_CONTEXT_SLOTS;
@@ skipping 1038 matching lines @@
       LineInfo* line_info = reinterpret_cast<LineInfo*>(event->user_data);
       PutLineInfo(reinterpret_cast<Address>(event->code_start), line_info);
       break;
     }
   }
 }
 #endif
 }  // namespace GDBJITInterface
 }  // namespace internal
 }  // namespace v8