[arm] CheckConstPool between TurboFan instructions.

Some TurboFan instructions block the literal pool for their entire
duration. If a long enough sequence of these instructions is
encountered, the literal pool can be blocked until it goes out of range.

Patch from issue 1236603002 at patchset 1 (http://crrev.com/1236603002#ps1).

BUG=v8:4292
LOG=y
R=jarin@chromium.org

Review URL: https://codereview.chromium.org/1232343002

Cr-Commit-Position: refs/heads/master@{#29587}

src/arm/assembler-arm-inl.h

@@ -433,9 +433,7 @@ void Assembler::CheckBuffer() {
   if (buffer_space() <= kGap) {
     GrowBuffer();
   }
-  if (pc_offset() >= next_buffer_check_) {
-    CheckConstPool(false, true);
-  }
+  MaybeCheckConstPool();
 }
 
 

src/arm/assembler-arm.h

@@ -1492,6 +1492,12 @@ class Assembler : public AssemblerBase {
   // Check if is time to emit a constant pool.
   void CheckConstPool(bool force_emit, bool require_jump);
 
+  void MaybeCheckConstPool() {
+    if (pc_offset() >= next_buffer_check_) {
+      CheckConstPool(false, true);
+    }
+  }
+
   int EmitEmbeddedConstantPool() {
     DCHECK(FLAG_enable_embedded_constant_pool);
     return constant_pool_builder_.Emit(this);

src/compiler/arm/code-generator-arm.cc

@@ -312,6 +312,8 @@ void CodeGenerator::AssembleDeconstructActivationRecord() {
 void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
   ArmOperandConverter i(this, instr);
 
+  masm()->MaybeCheckConstPool();
+
   switch (ArchOpcodeField::decode(instr->opcode())) {
     case kArchCallCodeObject: {
       EnsureSpaceForLazyDeopt();