A64: Tidy up Push and Pop TODOs.

src/a64/macro-assembler-a64.cc

Index: src/a64/macro-assembler-a64.cc
diff --git a/src/a64/macro-assembler-a64.cc b/src/a64/macro-assembler-a64.cc
index 14fb2fda63248808d25cdaa947fc4f61a2c6d9b3..b341044fb04515f46517621d6905d1523d4c0452 100644
--- a/src/a64/macro-assembler-a64.cc
+++ b/src/a64/macro-assembler-a64.cc
@@ -822,6 +822,56 @@ 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();
 
@@ -867,7 +917,7 @@ void MacroAssembler::PopCPURegList(CPURegList registers) {
 }
 
 
-void MacroAssembler::PushMultipleTimes(int count, Register src) {
+void MacroAssembler::PushMultipleTimes(CPURegister src, int count) {
   int size = src.SizeInBytes();
 
   PrepareForPush(count, size);
@@ -902,6 +952,51 @@ void MacroAssembler::PushMultipleTimes(int count, Register src) {
 }
 
 
+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,
@@ -983,30 +1078,39 @@ void MacroAssembler::PopHelper(int count, int size,
 }
 
 
-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.
+void MacroAssembler::PrepareForPush(Operand total_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.
-    ASSERT((count * size) % 16 == 0);
+    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.
   } 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(count * size);
+    BumpSystemStackPointer(total_size);
   }
 }
 
 
-void MacroAssembler::PrepareForPop(int count, int size) {
+void MacroAssembler::PrepareForPop(Operand total_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.
-    ASSERT((count * size) % 16 == 0);
+    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.
   }
 }
 
@@ -1102,15 +1206,24 @@ void MacroAssembler::PopCalleeSavedRegisters() {
 
 
 void MacroAssembler::AssertStackConsistency() {
-  if (emit_debug_code() && !csp.Is(StackPointer())) {
+  if (emit_debug_code()) {
     if (csp.Is(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);
+      // 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());
     }
   }
 }
@@ -4522,6 +4635,9 @@ void MacroAssembler::Abort(BailoutReason reason) {
   Mov(jssp, old_stack_pointer);
 
   if (use_real_aborts()) {
+    // Avoid infinite recursion; Push contains some assertions that use Abort.
+    NoUseRealAbortsScope no_real_aborts(this);
+
     Mov(x0, Operand(Smi::FromInt(reason)));
     Push(x0);