PPC: Fix constant pools for tail calls.

Constant pool must be marked as unavailable for use after the caller's pointer has been restored ahead of the tail call.

R=joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, ishell@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1641743002

Cr-Commit-Position: refs/heads/master@{#33563}

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

@@ -651,13 +651,7 @@ void CodeGenerator::AssemblePrepareTailCall(int stack_param_delta) {
     frame_access_state()->IncreaseSPDelta(-sp_slot_delta);
   }
   if (frame()->needs_frame()) {
-    if (FLAG_enable_embedded_constant_pool) {
-      __ LoadP(kConstantPoolRegister,
-               MemOperand(fp, StandardFrameConstants::kConstantPoolOffset));
-    }
-    __ LoadP(r0, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
-    __ LoadP(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
-    __ mtlr(r0);
+    __ RestoreFrameStateForTailCall();
   }
   frame_access_state()->SetFrameAccessToSP();
 }

src/ppc/builtins-ppc.cc

@@ -2077,13 +2077,7 @@ void PrepareForTailCall(MacroAssembler* masm, Register args_reg,
 
   // Restore caller's frame pointer and return address now as they will be
   // overwritten by the copying loop.
-  if (FLAG_enable_embedded_constant_pool) {
-    __ LoadP(kConstantPoolRegister,
-             MemOperand(fp, StandardFrameConstants::kConstantPoolOffset));
-  }
-  __ LoadP(r0, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
-  __ LoadP(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
-  __ mtlr(r0);
+  __ RestoreFrameStateForTailCall();
 
   // Now copy callee arguments to the caller frame going backwards to avoid
   // callee arguments corruption (source and destination areas could overlap).

src/ppc/macro-assembler-ppc.cc

@@ -564,6 +564,16 @@ void MacroAssembler::PopFixedFrame(Register marker_reg) {
   mtlr(r0);
 }
 
+void MacroAssembler::RestoreFrameStateForTailCall() {
+  if (FLAG_enable_embedded_constant_pool) {
+    LoadP(kConstantPoolRegister,
+          MemOperand(fp, StandardFrameConstants::kConstantPoolOffset));
+    set_constant_pool_available(false);
+  }
+  LoadP(r0, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
+  LoadP(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+  mtlr(r0);
+}
 
 const RegList MacroAssembler::kSafepointSavedRegisters = Register::kAllocatable;
 const int MacroAssembler::kNumSafepointSavedRegisters =

src/ppc/macro-assembler-ppc.h

@@ -342,6 +342,10 @@ class MacroAssembler : public Assembler {
   void PushFixedFrame(Register marker_reg = no_reg);
   void PopFixedFrame(Register marker_reg = no_reg);
 
+  // Restore caller's frame pointer and return address prior to being
+  // overwritten by tail call stack preparation.
+  void RestoreFrameStateForTailCall();
+
   // Push and pop the registers that can hold pointers, as defined by the
   // RegList constant kSafepointSavedRegisters.
   void PushSafepointRegisters();