Revert r19403: "A64: Tidy up Push and Pop TODOs."

Causes a64 debug asserts

TBR=jacob.bramley@arm.com,ulan@chromium.org

Review URL: https://codereview.chromium.org/169303007

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19419 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/a64/code-stubs-a64.cc

@@ -523,14 +523,11 @@ void HydrogenCodeStub::GenerateLightweightMiss(MacroAssembler* masm) {
     FrameScope scope(masm, StackFrame::INTERNAL);
     ASSERT((descriptor->register_param_count_ == 0) ||
            x0.Is(descriptor->register_params_[param_count - 1]));
-
     // Push arguments
-    MacroAssembler::PushPopQueue queue(masm);
+    // TODO(jbramley): Try to push these in blocks.
     for (int i = 0; i < param_count; ++i) {
-      queue.Queue(descriptor->register_params_[i]);
+      __ Push(descriptor->register_params_[i]);
     }
-    queue.PushQueued();
-
     ExternalReference miss = descriptor->miss_handler();
     __ CallExternalReference(miss, descriptor->register_param_count_);
   }

src/a64/full-codegen-a64.cc

@@ -183,7 +183,7 @@ void FullCodeGenerator::Generate() {
 
     if (locals_count > 0) {
       __ LoadRoot(x10, Heap::kUndefinedValueRootIndex);
-      __ PushMultipleTimes(x10, locals_count);
+      __ PushMultipleTimes(locals_count, x10);
     }
   }
 
@@ -4625,11 +4625,20 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
   __ Ldr(w10, FieldMemOperand(x10,
                               SharedFunctionInfo::kFormalParameterCountOffset));
   __ LoadRoot(the_hole, Heap::kTheHoleValueRootIndex);
-  __ PushMultipleTimes(the_hole, w10);
+
+  // TODO(jbramley): Write a variant of PushMultipleTimes which takes a register
+  // instead of a constant count, and use it to replace this loop.
+  Label push_argument_holes, push_frame;
+  __ Bind(&push_argument_holes);
+  __ Subs(w10, w10, 1);
+  __ B(mi, &push_frame);
+  __ Push(the_hole);
+  __ B(&push_argument_holes);
 
   // Enter a new JavaScript frame, and initialize its slots as they were when
   // the generator was suspended.
   Label resume_frame;
+  __ Bind(&push_frame);
   __ Bl(&resume_frame);
   __ B(&done);
 
@@ -4666,8 +4675,16 @@ void FullCodeGenerator::EmitGeneratorResume(Expression *generator,
 
   // Otherwise, we push holes for the operand stack and call the runtime to fix
   // up the stack and the handlers.
-  __ PushMultipleTimes(the_hole, operand_stack_size);
-
+  // TODO(jbramley): Write a variant of PushMultipleTimes which takes a register
+  // instead of a constant count, and use it to replace this loop.
+  Label push_operand_holes, call_resume;
+  __ Bind(&push_operand_holes);
+  __ Subs(operand_stack_size, operand_stack_size, 1);
+  __ B(mi, &call_resume);
+  __ Push(the_hole);
+  __ B(&push_operand_holes);
+
+  __ Bind(&call_resume);
   __ Mov(x10, Operand(Smi::FromInt(resume_mode)));
   __ Push(generator_object, result_register(), x10);
   __ CallRuntime(Runtime::kResumeJSGeneratorObject, 3);

src/a64/macro-assembler-a64-inl.h

@@ -1286,9 +1286,8 @@ void MacroAssembler::BumpSystemStackPointer(const Operand& space) {
   ASSERT(!csp.Is(sp_));
   // TODO(jbramley): Several callers rely on this not using scratch registers,
   // so we use the assembler directly here. However, this means that large
-  // immediate values of 'space' cannot be handled cleanly. Once we implement
-  // our flexible scratch register idea, we could greatly simplify this
-  // function.
+  // immediate values of 'space' cannot be handled. Once we merge with V8, we
+  // should try to use the new scope that controls scratch register usage.
   InstructionAccurateScope scope(this);
   if ((space.IsImmediate()) && !is_uint12(space.immediate())) {
     // The subtract instruction supports a 12-bit immediate, shifted left by

src/a64/macro-assembler-a64.cc

@@ -623,56 +623,6 @@ void MacroAssembler::Pop(const CPURegister& dst0, const CPURegister& dst1,
 }
 
 
-void MacroAssembler::PushPopQueue::PushQueued() {
-  if (queued_.empty()) return;
-
-  masm_->PrepareForPush(size_);
-
-  int count = queued_.size();
-  int index = 0;
-  while (index < count) {
-    // PushHelper can only handle registers with the same size and type, and it
-    // can handle only four at a time. Batch them up accordingly.
-    CPURegister batch[4] = {NoReg, NoReg, NoReg, NoReg};
-    int batch_index = 0;
-    do {
-      batch[batch_index++] = queued_[index++];
-    } while ((batch_index < 4) && (index < count) &&
-             batch[0].IsSameSizeAndType(queued_[index]));
-
-    masm_->PushHelper(batch_index, batch[0].SizeInBytes(),
-                      batch[0], batch[1], batch[2], batch[3]);
-  }
-
-  queued_.clear();
-}
-
-
-void MacroAssembler::PushPopQueue::PopQueued() {
-  if (queued_.empty()) return;
-
-  masm_->PrepareForPop(size_);
-
-  int count = queued_.size();
-  int index = 0;
-  while (index < count) {
-    // PopHelper can only handle registers with the same size and type, and it
-    // can handle only four at a time. Batch them up accordingly.
-    CPURegister batch[4] = {NoReg, NoReg, NoReg, NoReg};
-    int batch_index = 0;
-    do {
-      batch[batch_index++] = queued_[index++];
-    } while ((batch_index < 4) && (index < count) &&
-             batch[0].IsSameSizeAndType(queued_[index]));
-
-    masm_->PopHelper(batch_index, batch[0].SizeInBytes(),
-                     batch[0], batch[1], batch[2], batch[3]);
-  }
-
-  queued_.clear();
-}
-
-
 void MacroAssembler::PushCPURegList(CPURegList registers) {
   int size = registers.RegisterSizeInBytes();
 
@@ -718,7 +668,7 @@ void MacroAssembler::PopCPURegList(CPURegList registers) {
 }
 
 
-void MacroAssembler::PushMultipleTimes(CPURegister src, int count) {
+void MacroAssembler::PushMultipleTimes(int count, Register src) {
   int size = src.SizeInBytes();
 
   PrepareForPush(count, size);
@@ -753,51 +703,6 @@ void MacroAssembler::PushMultipleTimes(CPURegister src, int count) {
 }
 
 
-void MacroAssembler::PushMultipleTimes(CPURegister src, Register count) {
-  PrepareForPush(Operand(count, UXTW, WhichPowerOf2(src.SizeInBytes())));
-
-  Register temp = AppropriateTempFor(count);
-
-  if (FLAG_optimize_for_size) {
-    Label loop, done;
-
-    Subs(temp, count, 1);
-    B(mi, &done);
-
-    // Push all registers individually, to save code size.
-    Bind(&loop);
-    Subs(temp, temp, 1);
-    PushHelper(1, src.SizeInBytes(), src, NoReg, NoReg, NoReg);
-    B(pl, &loop);
-
-    Bind(&done);
-  } else {
-    Label loop, leftover2, leftover1, done;
-
-    Subs(temp, count, 4);
-    B(mi, &leftover2);
-
-    // Push groups of four first.
-    Bind(&loop);
-    Subs(temp, temp, 4);
-    PushHelper(4, src.SizeInBytes(), src, src, src, src);
-    B(pl, &loop);
-
-    // Push groups of two.
-    Bind(&leftover2);
-    Tbz(count, 1, &leftover1);
-    PushHelper(2, src.SizeInBytes(), src, src, NoReg, NoReg);
-
-    // Push the last one (if required).
-    Bind(&leftover1);
-    Tbz(count, 0, &done);
-    PushHelper(1, src.SizeInBytes(), src, NoReg, NoReg, NoReg);
-
-    Bind(&done);
-  }
-}
-
-
 void MacroAssembler::PushHelper(int count, int size,
                                 const CPURegister& src0,
                                 const CPURegister& src1,
@@ -879,39 +784,30 @@ void MacroAssembler::PopHelper(int count, int size,
 }
 
 
-void MacroAssembler::PrepareForPush(Operand total_size) {
-  AssertStackConsistency();
+void MacroAssembler::PrepareForPush(int count, int size) {
+  // TODO(jbramley): Use AssertStackConsistency here, if possible. See the
+  // AssertStackConsistency for details of why we can't at the moment.
   if (csp.Is(StackPointer())) {
     // If the current stack pointer is csp, then it must be aligned to 16 bytes
     // on entry and the total size of the specified registers must also be a
     // multiple of 16 bytes.
-    if (total_size.IsImmediate()) {
-      ASSERT((total_size.immediate() % 16) == 0);
-    }
-
-    // Don't check access size for non-immediate sizes. It's difficult to do
-    // well, and it will be caught by hardware (or the simulator) anyway.
+    ASSERT((count * size) % 16 == 0);
   } else {
     // Even if the current stack pointer is not the system stack pointer (csp),
     // the system stack pointer will still be modified in order to comply with
     // ABI rules about accessing memory below the system stack pointer.
-    BumpSystemStackPointer(total_size);
+    BumpSystemStackPointer(count * size);
   }
 }
 
 
-void MacroAssembler::PrepareForPop(Operand total_size) {
+void MacroAssembler::PrepareForPop(int count, int size) {
   AssertStackConsistency();
   if (csp.Is(StackPointer())) {
     // If the current stack pointer is csp, then it must be aligned to 16 bytes
     // on entry and the total size of the specified registers must also be a
     // multiple of 16 bytes.
-    if (total_size.IsImmediate()) {
-      ASSERT((total_size.immediate() % 16) == 0);
-    }
-
-    // Don't check access size for non-immediate sizes. It's difficult to do
-    // well, and it will be caught by hardware (or the simulator) anyway.
+    ASSERT((count * size) % 16 == 0);
   }
 }
 
@@ -1007,24 +903,15 @@ void MacroAssembler::PopCalleeSavedRegisters() {
 
 
 void MacroAssembler::AssertStackConsistency() {
-  if (emit_debug_code()) {
+  if (emit_debug_code() && !csp.Is(StackPointer())) {
     if (csp.Is(StackPointer())) {
-      // We can't check the alignment of csp without using a scratch register
-      // (or clobbering the flags), but the processor (or simulator) will abort
-      // if it is not properly aligned during a load.
-      ldr(xzr, MemOperand(csp, 0));
-    } else if (FLAG_enable_slow_asserts) {
-      Label ok;
-      // Check that csp <= StackPointer(), preserving all registers and NZCV.
-      sub(StackPointer(), csp, StackPointer());
-      cbz(StackPointer(), &ok);                 // Ok if csp == StackPointer().
-      tbnz(StackPointer(), kXSignBit, &ok);     // Ok if csp < StackPointer().
-
-      Abort(kTheCurrentStackPointerIsBelowCsp);
-
-      bind(&ok);
-      // Restore StackPointer().
-      sub(StackPointer(), csp, StackPointer());
+      // TODO(jbramley): Check for csp alignment if it is the stack pointer.
+    } else {
+      // TODO(jbramley): Currently we cannot use this assertion in Push because
+      // some calling code assumes that the flags are preserved. For an example,
+      // look at Builtins::Generate_ArgumentsAdaptorTrampoline.
+      Cmp(csp, StackPointer());
+      Check(ls, kTheCurrentStackPointerIsBelowCsp);
     }
   }
 }
@@ -4432,9 +4319,6 @@ void MacroAssembler::Abort(BailoutReason reason) {
   Adr(x0, &msg_address);
 
   if (use_real_aborts()) {
-    // Avoid infinite recursion; Push contains some assertions that use Abort.
-    NoUseRealAbortsScope no_real_aborts(this);
-
     // Split the message pointer into two SMI to avoid the GC
     // trying to scan the string.
     STATIC_ASSERT((kSmiShift == 32) && (kSmiTag == 0));

src/a64/macro-assembler-a64.h

@@ -28,8 +28,6 @@
 #ifndef V8_A64_MACRO_ASSEMBLER_A64_H_
 #define V8_A64_MACRO_ASSEMBLER_A64_H_
 
-#include <vector>
-
 #include "v8globals.h"
 #include "globals.h"
 
@@ -519,8 +517,7 @@ class MacroAssembler : public Assembler {
   }
 
   // Push the specified register 'count' times.
-  void PushMultipleTimes(CPURegister src, Register count);
-  void PushMultipleTimes(CPURegister src, int count);
+  void PushMultipleTimes(int count, Register src);
 
   // This is a convenience method for pushing a single Handle<Object>.
   inline void Push(Handle<Object> handle);
@@ -534,35 +531,6 @@ class MacroAssembler : public Assembler {
     Pop(dst);
   }
 
-  // Sometimes callers need to push or pop multiple registers in a way that is
-  // difficult to structure efficiently for fixed Push or Pop calls. This scope
-  // allows push requests to be queued up, then flushed at once. The
-  // MacroAssembler will try to generate the most efficient sequence required.
-  //
-  // Unlike the other Push and Pop macros, PushPopQueue can handle mixed sets of
-  // register sizes and types.
-  class PushPopQueue {
-   public:
-    explicit PushPopQueue(MacroAssembler* masm) : masm_(masm), size_(0) { }
-
-    ~PushPopQueue() {
-      ASSERT(queued_.empty());
-    }
-
-    void Queue(const CPURegister& rt) {
-      size_ += rt.SizeInBytes();
-      queued_.push_back(rt);
-    }
-
-    void PushQueued();
-    void PopQueued();
-
-   private:
-    MacroAssembler* masm_;
-    int size_;
-    std::vector<CPURegister> queued_;
-  };
-
   // Poke 'src' onto the stack. The offset is in bytes.
   //
   // If the current stack pointer (according to StackPointer()) is csp, then
@@ -2035,12 +2003,9 @@ class MacroAssembler : public Assembler {
 
   // Perform necessary maintenance operations before a push or pop.
   //
-  // Note that size is specified in bytes.
-  void PrepareForPush(Operand total_size);
-  void PrepareForPop(Operand total_size);
-
-  void PrepareForPush(int count, int size) { PrepareForPush(count * size); }
-  void PrepareForPop(int count, int size) { PrepareForPop(count * size); }
+  // Note that size is per register, and is specified in bytes.
+  void PrepareForPush(int count, int size);
+  void PrepareForPop(int count, int size);
 
   // Call Printf. On a native build, a simple call will be generated, but if the
   // simulator is being used then a suitable pseudo-instruction is used. The

src/a64/stub-cache-a64.cc

@@ -754,16 +754,14 @@ void StubCompiler::GenerateFastApiCall(MacroAssembler* masm,
                                        int argc,
                                        Register* values) {
   ASSERT(!AreAliased(receiver, scratch));
-
-  MacroAssembler::PushPopQueue queue(masm);
-  queue.Queue(receiver);
-  // Write the arguments to the stack frame.
+  __ Push(receiver);
+  // Write the arguments to stack frame.
   for (int i = 0; i < argc; i++) {
+    // TODO(jbramley): Push these in as few Push() calls as possible.
     Register arg = values[argc-1-i];
     ASSERT(!AreAliased(receiver, scratch, arg));
-    queue.Queue(arg);
+    __ Push(arg);
   }
-  queue.PushQueued();
 
   ASSERT(optimization.is_simple_api_call());
 

src/objects.h

@@ -1332,7 +1332,6 @@ class MaybeObject BASE_EMBEDDED {
     "The instruction to patch should be an ori")                              \
   V(kTheSourceAndDestinationAreTheSame,                                       \
     "The source and destination are the same")                                \
-  V(kTheStackPointerIsNotAligned, "The stack pointer is not aligned.")        \
   V(kTheStackWasCorruptedByMacroAssemblerCall,                                \
     "The stack was corrupted by MacroAssembler::Call()")                      \
   V(kTooManyParametersLocals, "Too many parameters/locals")                   \

test/cctest/test-assembler-a64.cc

@@ -8110,8 +8110,7 @@ static void PushPopJsspWXOverlapHelper(int reg_count, int claim) {
   SETUP_SIZE(BUF_SIZE * 2);
 
   // Work out which registers to use, based on reg_size.
-  Register tmp = x8;
-  static RegList const allowed = ~(tmp.Bit() | jssp.Bit());
+  static RegList const allowed = ~(x8.Bit() | x9.Bit() | jssp.Bit());
   if (reg_count == kPushPopJsspMaxRegCount) {
     reg_count = CountSetBits(allowed, kNumberOfRegisters);
   }
@@ -8197,13 +8196,7 @@ static void PushPopJsspWXOverlapHelper(int reg_count, int claim) {
       int times = i % 4 + 1;
       if (i & 1) {
         // Push odd-numbered registers as W registers.
-        if (i & 2) {
-          __ PushMultipleTimes(w[i], times);
-        } else {
-          // Use a register to specify the count.
-          __ Mov(tmp.W(), times);
-          __ PushMultipleTimes(w[i], tmp.W());
-        }
+        __ PushMultipleTimes(times, w[i]);
         // Fill in the expected stack slots.
         for (int j = 0; j < times; j++) {
           if (w[i].Is(wzr)) {
@@ -8215,13 +8208,7 @@ static void PushPopJsspWXOverlapHelper(int reg_count, int claim) {
         }
       } else {
         // Push even-numbered registers as X registers.
-        if (i & 2) {
-          __ PushMultipleTimes(x[i], times);
-        } else {
-          // Use a register to specify the count.
-          __ Mov(tmp, times);
-          __ PushMultipleTimes(x[i], tmp);
-        }
+        __ PushMultipleTimes(times, x[i]);
         // Fill in the expected stack slots.
         for (int j = 0; j < times; j++) {
           if (x[i].IsZero()) {
@@ -8412,156 +8399,6 @@ TEST(push_pop_csp) {
 }
 
 
-TEST(push_queued) {
-  INIT_V8();
-  SETUP();
-
-  START();
-
-  ASSERT(__ StackPointer().Is(csp));
-  __ Mov(jssp, __ StackPointer());
-  __ SetStackPointer(jssp);
-
-  MacroAssembler::PushPopQueue queue(&masm);
-
-  // Queue up registers.
-  queue.Queue(x0);
-  queue.Queue(x1);
-  queue.Queue(x2);
-  queue.Queue(x3);
-
-  queue.Queue(w4);
-  queue.Queue(w5);
-  queue.Queue(w6);
-
-  queue.Queue(d0);
-  queue.Queue(d1);
-
-  queue.Queue(s2);
-
-  __ Mov(x0, 0x1234000000000000);
-  __ Mov(x1, 0x1234000100010001);
-  __ Mov(x2, 0x1234000200020002);
-  __ Mov(x3, 0x1234000300030003);
-  __ Mov(w4, 0x12340004);
-  __ Mov(w5, 0x12340005);
-  __ Mov(w6, 0x12340006);
-  __ Fmov(d0, 123400.0);
-  __ Fmov(d1, 123401.0);
-  __ Fmov(s2, 123402.0);
-
-  // Actually push them.
-  queue.PushQueued();
-
-  Clobber(&masm, CPURegList(CPURegister::kRegister, kXRegSize, 0, 6));
-  Clobber(&masm, CPURegList(CPURegister::kFPRegister, kDRegSize, 0, 2));
-
-  // Pop them conventionally.
-  __ Pop(s2);
-  __ Pop(d1, d0);
-  __ Pop(w6, w5, w4);
-  __ Pop(x3, x2, x1, x0);
-
-  __ Mov(csp, __ StackPointer());
-  __ SetStackPointer(csp);
-
-  END();
-
-  RUN();
-
-  ASSERT_EQUAL_64(0x1234000000000000, x0);
-  ASSERT_EQUAL_64(0x1234000100010001, x1);
-  ASSERT_EQUAL_64(0x1234000200020002, x2);
-  ASSERT_EQUAL_64(0x1234000300030003, x3);
-
-  ASSERT_EQUAL_32(0x12340004, w4);
-  ASSERT_EQUAL_32(0x12340005, w5);
-  ASSERT_EQUAL_32(0x12340006, w6);
-
-  ASSERT_EQUAL_FP64(123400.0, d0);
-  ASSERT_EQUAL_FP64(123401.0, d1);
-
-  ASSERT_EQUAL_FP32(123402.0, s2);
-
-  TEARDOWN();
-}
-
-
-TEST(pop_queued) {
-  INIT_V8();
-  SETUP();
-
-  START();
-
-  ASSERT(__ StackPointer().Is(csp));
-  __ Mov(jssp, __ StackPointer());
-  __ SetStackPointer(jssp);
-
-  MacroAssembler::PushPopQueue queue(&masm);
-
-  __ Mov(x0, 0x1234000000000000);
-  __ Mov(x1, 0x1234000100010001);
-  __ Mov(x2, 0x1234000200020002);
-  __ Mov(x3, 0x1234000300030003);
-  __ Mov(w4, 0x12340004);
-  __ Mov(w5, 0x12340005);
-  __ Mov(w6, 0x12340006);
-  __ Fmov(d0, 123400.0);
-  __ Fmov(d1, 123401.0);
-  __ Fmov(s2, 123402.0);
-
-  // Push registers conventionally.
-  __ Push(x0, x1, x2, x3);
-  __ Push(w4, w5, w6);
-  __ Push(d0, d1);
-  __ Push(s2);
-
-  // Queue up a pop.
-  queue.Queue(s2);
-
-  queue.Queue(d1);
-  queue.Queue(d0);
-
-  queue.Queue(w6);
-  queue.Queue(w5);
-  queue.Queue(w4);
-
-  queue.Queue(x3);
-  queue.Queue(x2);
-  queue.Queue(x1);
-  queue.Queue(x0);
-
-  Clobber(&masm, CPURegList(CPURegister::kRegister, kXRegSize, 0, 6));
-  Clobber(&masm, CPURegList(CPURegister::kFPRegister, kDRegSize, 0, 2));
-
-  // Actually pop them.
-  queue.PopQueued();
-
-  __ Mov(csp, __ StackPointer());
-  __ SetStackPointer(csp);
-
-  END();
-
-  RUN();
-
-  ASSERT_EQUAL_64(0x1234000000000000, x0);
-  ASSERT_EQUAL_64(0x1234000100010001, x1);
-  ASSERT_EQUAL_64(0x1234000200020002, x2);
-  ASSERT_EQUAL_64(0x1234000300030003, x3);
-
-  ASSERT_EQUAL_64(0x0000000012340004, x4);
-  ASSERT_EQUAL_64(0x0000000012340005, x5);
-  ASSERT_EQUAL_64(0x0000000012340006, x6);
-
-  ASSERT_EQUAL_FP64(123400.0, d0);
-  ASSERT_EQUAL_FP64(123401.0, d1);
-
-  ASSERT_EQUAL_FP32(123402.0, s2);
-
-  TEARDOWN();
-}
-
-
 TEST(jump_both_smi) {
   INIT_V8();
   SETUP();