MIPS: Use JIC/JIALC offset when possible

src/mips/macro-assembler-mips.cc

 // Copyright 2012 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 <limits.h>  // For LONG_MIN, LONG_MAX.
 
 #if V8_TARGET_ARCH_MIPS
 
 #include "src/base/bits.h"
 #include "src/base/division-by-constant.h"
@@ skipping 3649 matching lines @@
     DCHECK(offset == 0);
     if (IsMipsArchVariant(kMips32r6) && bdslot == PROTECT) {
       return BranchAndLinkShortHelperR6(0, L, cond, rs, rt);
     } else {
       return BranchAndLinkShortHelper(0, L, cond, rs, rt, bdslot);
     }
   }
   return false;
 }
 
-
-void MacroAssembler::Jump(Register target,
-                          Condition cond,
-                          Register rs,
-                          const Operand& rt,
-                          BranchDelaySlot bd) {
+void MacroAssembler::Jump(Register target, uint32_t offset, Condition cond,
+                          Register rs, const Operand& rt, BranchDelaySlot bd) {
   BlockTrampolinePoolScope block_trampoline_pool(this);
   if (IsMipsArchVariant(kMips32r6) && bd == PROTECT) {
     if (cond == cc_always) {
-      jic(target, 0);
+      jic(target, offset);
     } else {
       BRANCH_ARGS_CHECK(cond, rs, rt);
       Branch(2, NegateCondition(cond), rs, rt);
-      jic(target, 0);
+      jic(target, offset);
     }
   } else {
     if (cond == cc_always) {

[ivica.bogosavljevic, 2016/12/05 10:48:48]

What happens in this branch if offset != 0. We should add additional
instructions in case offset != 0

[miran.karic, 2016/12/05 12:44:48]

Currently offset is used only for r6, so here it is always 0. Perhaps though,
maybe it would make sense to use Jump/Call with offset to set the address
instead of doing it before Jump/Call. This would place add/li instructions
inside Jump/Call and we would check architecture only here.

       jr(target);
     } else {
       BRANCH_ARGS_CHECK(cond, rs, rt);
       Branch(2, NegateCondition(cond), rs, rt);
       jr(target);
     }
     // Emit a nop in the branch delay slot if required.
     if (bd == PROTECT) nop();
   }
 }
 
 
 void MacroAssembler::Jump(intptr_t target,
                           RelocInfo::Mode rmode,
                           Condition cond,
                           Register rs,
                           const Operand& rt,
                           BranchDelaySlot bd) {
   Label skip;
   if (cond != cc_always) {
     Branch(USE_DELAY_SLOT, &skip, NegateCondition(cond), rs, rt);
   }
   // The first instruction of 'li' may be placed in the delay slot.
   // This is not an issue, t9 is expected to be clobbered anyway.
-  li(t9, Operand(target, rmode));
-  Jump(t9, al, zero_reg, Operand(zero_reg), bd);
+  if (IsMipsArchVariant(kMips32r6) && bd == PROTECT) {
+    uint32_t lui_offset, jic_offset;
+    UnpackTargetAddressUnsigned(target, lui_offset, jic_offset);
+    if (MustUseReg(rmode)) {
+      RecordRelocInfo(rmode, target);

[ivica.bogosavljevic, 2016/12/05 10:48:48]

Why are we recording reloc info for mipsr6 but not for mipsr2?

[miran.karic, 2016/12/05 12:44:48]

We do it in li() for lui, ori, and here for lui, jic.

+    }
+    lui(t9, lui_offset);
+    Jump(t9, jic_offset, al, zero_reg, Operand(zero_reg), bd);
+  } else {
+    li(t9, Operand(target, rmode));
+    Jump(t9, 0, al, zero_reg, Operand(zero_reg), bd);
+  }
   bind(&skip);
 }
 
 
 void MacroAssembler::Jump(Address target,
                           RelocInfo::Mode rmode,
                           Condition cond,
                           Register rs,
                           const Operand& rt,
                           BranchDelaySlot bd) {
@@ skipping 27 matching lines @@
     size += 3;
   }
 
   if (bd == PROTECT && !IsMipsArchVariant(kMips32r6)) size += 1;
 
   return size * kInstrSize;
 }
 
 
 // Note: To call gcc-compiled C code on mips, you must call thru t9.
-void MacroAssembler::Call(Register target,
-                          Condition cond,
-                          Register rs,
-                          const Operand& rt,
-                          BranchDelaySlot bd) {
+void MacroAssembler::Call(Register target, uint32_t offset, Condition cond,
+                          Register rs, const Operand& rt, BranchDelaySlot bd) {
 #ifdef DEBUG
   int size = IsPrevInstrCompactBranch() ? kInstrSize : 0;
 #endif
 
   BlockTrampolinePoolScope block_trampoline_pool(this);
   Label start;
   bind(&start);
   if (IsMipsArchVariant(kMips32r6) && bd == PROTECT) {
     if (cond == cc_always) {
-      jialc(target, 0);
+      jialc(target, offset);
     } else {
       BRANCH_ARGS_CHECK(cond, rs, rt);
       Branch(2, NegateCondition(cond), rs, rt);
-      jialc(target, 0);
+      jialc(target, offset);
     }
   } else {
     if (cond == cc_always) {
       jalr(target);

[ivica.bogosavljevic, 2016/12/05 10:48:47]

samo as for Jump

     } else {
       BRANCH_ARGS_CHECK(cond, rs, rt);
       Branch(2, NegateCondition(cond), rs, rt);
       jalr(target);
     }
     // Emit a nop in the branch delay slot if required.
     if (bd == PROTECT) nop();
   }
 
 #ifdef DEBUG
   CHECK_EQ(size + CallSize(target, cond, rs, rt, bd),
            SizeOfCodeGeneratedSince(&start));
 #endif
 }
 
 
 int MacroAssembler::CallSize(Address target,
                              RelocInfo::Mode rmode,
                              Condition cond,
                              Register rs,
                              const Operand& rt,
                              BranchDelaySlot bd) {
   int size = CallSize(t9, cond, rs, rt, bd);
-  return size + 2 * kInstrSize;
+  if (IsMipsArchVariant(kMips32r6) && bd == PROTECT && cond == cc_always)
+    return size + 1 * kInstrSize;
+  else
+    return size + 2 * kInstrSize;
 }
 
 
 void MacroAssembler::Call(Address target,
                           RelocInfo::Mode rmode,
                           Condition cond,
                           Register rs,
                           const Operand& rt,
                           BranchDelaySlot bd) {
   BlockTrampolinePoolScope block_trampoline_pool(this);
   Label start;
   bind(&start);
   int32_t target_int = reinterpret_cast<int32_t>(target);
-  li(t9, Operand(target_int, rmode), CONSTANT_SIZE);
-  Call(t9, cond, rs, rt, bd);
+  if (IsMipsArchVariant(kMips32r6) && bd == PROTECT && cond == cc_always) {
+    uint32_t lui_offset, jialc_offset;
+    UnpackTargetAddressUnsigned(target_int, lui_offset, jialc_offset);
+    if (MustUseReg(rmode)) {
+      RecordRelocInfo(rmode, target_int);

[ivica.bogosavljevic, 2016/12/05 10:48:47]

same as for :Call from above

+    }
+    lui(t9, lui_offset);
+    Call(t9, jialc_offset, cond, rs, rt, bd);
+  } else {
+    li(t9, Operand(target_int, rmode), CONSTANT_SIZE);
+    Call(t9, 0, cond, rs, rt, bd);
+  }
   DCHECK_EQ(CallSize(target, rmode, cond, rs, rt, bd),
             SizeOfCodeGeneratedSince(&start));
 }
 
 
 int MacroAssembler::CallSize(Handle<Code> code,
                              RelocInfo::Mode rmode,
                              TypeFeedbackId ast_id,
                              Condition cond,
                              Register rs,
@@ skipping 24 matching lines @@
   Call(reinterpret_cast<Address>(code.location()), rmode, cond, rs, rt, bd);
   DCHECK_EQ(CallSize(code, rmode, ast_id, cond, rs, rt, bd),
             SizeOfCodeGeneratedSince(&start));
 }
 
 
 void MacroAssembler::Ret(Condition cond,
                          Register rs,
                          const Operand& rt,
                          BranchDelaySlot bd) {
-  Jump(ra, cond, rs, rt, bd);
+  Jump(ra, 0, cond, rs, rt, bd);
 }
 
 
 void MacroAssembler::BranchLong(Label* L, BranchDelaySlot bdslot) {
   if (IsMipsArchVariant(kMips32r6) && bdslot == PROTECT &&
       (!L->is_bound() || is_near_r6(L))) {
     BranchShortHelperR6(0, L);
   } else {
     BlockTrampolinePoolScope block_trampoline_pool(this);
     uint32_t imm32;
@@ skipping 33 matching lines @@
 
 void MacroAssembler::BranchAndLinkLong(Label* L, BranchDelaySlot bdslot) {
   if (IsMipsArchVariant(kMips32r6) && bdslot == PROTECT &&
       (!L->is_bound() || is_near_r6(L))) {
     BranchAndLinkShortHelperR6(0, L);
   } else {
     BlockTrampolinePoolScope block_trampoline_pool(this);
     uint32_t imm32;
     imm32 = jump_address(L);
     if (IsMipsArchVariant(kMips32r6) && bdslot == PROTECT) {
-      uint32_t lui_offset, jic_offset;
-      UnpackTargetAddressUnsigned(imm32, lui_offset, jic_offset);
+      uint32_t lui_offset, jialc_offset;
+      UnpackTargetAddressUnsigned(imm32, lui_offset, jialc_offset);
       {
         BlockGrowBufferScope block_buf_growth(this);
         // Buffer growth (and relocation) must be blocked for internal
         // references until associated instructions are emitted and
         // available to be patched.
         RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE_ENCODED);
         lui(at, lui_offset);
-        jialc(at, jic_offset);
+        jialc(at, jialc_offset);
       }
       CheckBuffer();
     } else {
       {
         BlockGrowBufferScope block_buf_growth(this);
         // Buffer growth (and relocation) must be blocked for internal
         // references
         // until associated instructions are emitted and available to be
         // patched.
         RecordRelocInfo(RelocInfo::INTERNAL_REFERENCE_ENCODED);
@@ skipping 2325 matching lines @@
 
 void MacroAssembler::PrepareCallCFunction(int num_reg_arguments,
                                           Register scratch) {
   PrepareCallCFunction(num_reg_arguments, 0, scratch);
 }
 
 
 void MacroAssembler::CallCFunction(ExternalReference function,
                                    int num_reg_arguments,
                                    int num_double_arguments) {
-  li(t8, Operand(function));
-  CallCFunctionHelper(t8, num_reg_arguments, num_double_arguments);
+  if (IsMipsArchVariant(kMips32r6)) {
+    uint32_t lui_offset, jialc_offset;
+    UnpackTargetAddressUnsigned(Operand(function).immediate(), lui_offset,
+                                jialc_offset);
+    if (MustUseReg(Operand(function).rmode())) {
+      RecordRelocInfo(Operand(function).rmode(), Operand(function).immediate());
+    }
+    lui(t9, lui_offset);
+    CallCFunctionHelper(t9, num_reg_arguments, num_double_arguments,
+                        jialc_offset);
+  } else {
+    li(t9, Operand(function));
+    CallCFunctionHelper(t9, num_reg_arguments, num_double_arguments);
+  }
 }
 
 
 void MacroAssembler::CallCFunction(Register function,
                                    int num_reg_arguments,
                                    int num_double_arguments) {
   CallCFunctionHelper(function, num_reg_arguments, num_double_arguments);
 }
 
 
 void MacroAssembler::CallCFunction(ExternalReference function,
                                    int num_arguments) {
   CallCFunction(function, num_arguments, 0);
 }
 
 
 void MacroAssembler::CallCFunction(Register function,
                                    int num_arguments) {
   CallCFunction(function, num_arguments, 0);
 }
 
-
 void MacroAssembler::CallCFunctionHelper(Register function,
                                          int num_reg_arguments,
-                                         int num_double_arguments) {
+                                         int num_double_arguments,
+                                         uint32_t offset) {
   DCHECK(has_frame());
   // Make sure that the stack is aligned before calling a C function unless
   // running in the simulator. The simulator has its own alignment check which
   // provides more information.
   // The argument stots are presumed to have been set up by
   // PrepareCallCFunction. The C function must be called via t9, for mips ABI.
 
 #if V8_HOST_ARCH_MIPS
   if (emit_debug_code()) {
     int frame_alignment = base::OS::ActivationFrameAlignment();
@@ skipping 13 matching lines @@
 
   // Just call directly. The function called cannot cause a GC, or
   // allow preemption, so the return address in the link register
   // stays correct.
 
   if (!function.is(t9)) {
     mov(t9, function);
     function = t9;
   }
 
-  Call(function);
+  Call(function, offset);
 
   int stack_passed_arguments = CalculateStackPassedWords(
       num_reg_arguments, num_double_arguments);
 
   if (base::OS::ActivationFrameAlignment() > kPointerSize) {
     lw(sp, MemOperand(sp, stack_passed_arguments * kPointerSize));
   } else {
     Addu(sp, sp, Operand(stack_passed_arguments * kPointerSize));
   }
 }
@@ skipping 397 matching lines @@
   if (mag.shift > 0) sra(result, result, mag.shift);
   srl(at, dividend, 31);
   Addu(result, result, Operand(at));
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS