MIPS64: Improve long branches utilizing code range.

src/heap/spaces.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/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/full-codegen.h"
 #include "src/heap/mark-compact.h"
@@ skipping 96 matching lines @@
     } else {
       return true;
     }
   }
 
   if (requested <= kMinimumCodeRangeSize) {
     requested = kMinimumCodeRangeSize;
   }
 
   DCHECK(!kRequiresCodeRange || requested <= kMaximalCodeRangeSize);
+#ifdef V8_TARGET_ARCH_MIPS64
+  // To use pseudo-relative jumps such as j/jal instructions which have 28-bit
+  // encoded immediate, the addresses have to be in range of 256Mb aligned
+  // region.
+  code_range_ = new base::VirtualMemory(requested, kMaximalCodeRangeSize);
+#else
   code_range_ = new base::VirtualMemory(requested);
+#endif
   CHECK(code_range_ != NULL);
   if (!code_range_->IsReserved()) {
     delete code_range_;
     code_range_ = NULL;
     return false;
   }
 
   // We are sure that we have mapped a block of requested addresses.
   DCHECK(code_range_->size() == requested);
   Address base = reinterpret_cast<Address>(code_range_->address());
@@ skipping 510 matching lines @@
       LOG(isolate_, StringEvent("MemoryAllocator::AllocateRawMemory",
                                 "V8 Executable Allocation capacity exceeded"));
       return NULL;
     }
 
     // Size of header (not executable) plus area (executable).
     size_t commit_size = RoundUp(CodePageGuardStartOffset() + commit_area_size,
                                  base::OS::CommitPageSize());
     // Allocate executable memory either from code range or from the
     // OS.
+#ifdef V8_TARGET_ARCH_MIPS64
+    // Use code range only for large object space on mips64 to keep address
+    // range within 256-MB memory region.
+    if (isolate_->code_range() != NULL && isolate_->code_range()->valid() &&
+        commit_size > CodePageAreaSize()) {

[Erik Corry, 2015/06/04 10:28:15]

The commit_size includes the CodePageGuardStartOffset(), but the
CodePageAreaSize does not include it. It looks like you are comparing two
incomparable things here and I suspect it always takes normal pages from the
reserved area instead of allocating them individually.

[dusmil.imgtec, 2015/06/04 11:04:40]

Done.

[dusmil.imgtec, 2015/06/04 11:04:40]

Thank you for spotting this, typo mistake sorry. Too many variables with the
similar names.

+#else
     if (isolate_->code_range() != NULL && isolate_->code_range()->valid()) {
+#endif
       base = isolate_->code_range()->AllocateRawMemory(chunk_size, commit_size,
                                                        &chunk_size);
       DCHECK(
           IsAligned(reinterpret_cast<intptr_t>(base), MemoryChunk::kAlignment));
       if (base == NULL) return NULL;
       size_ += chunk_size;
       // Update executable memory size.
       size_executable_ += chunk_size;
     } else {
       base = AllocateAlignedMemory(chunk_size, commit_size,
@@ skipping 2474 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }
 }  // namespace v8::internal