Stop creating dummy call frames when calling out to C functions

runtime/vm/intermediate_language_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 3962 matching lines @@
 
 
 LocationSummary* MathUnaryInstr::MakeLocationSummary(bool opt) const {
   if ((kind() == MethodRecognizer::kMathSin) ||
       (kind() == MethodRecognizer::kMathCos)) {
     // Calling convention on x64 uses XMM0 and XMM1 to pass the first two
     // double arguments and XMM0 to return the result. Unfortunately
     // currently we can't specify these registers because ParallelMoveResolver
     // assumes that XMM0 is free at all times.
     // TODO(vegorov): allow XMM0 to be used.
-    const intptr_t kNumTemps = 0;
+    const intptr_t kNumTemps = 1;
     LocationSummary* summary =
         new LocationSummary(InputCount(), kNumTemps, LocationSummary::kCall);
     summary->set_in(0, Location::FpuRegisterLocation(XMM1));
+    // R13 is chosen because it is callee saved so we do not need to back it
+    // up before calling into the runtime.
+    summary->set_temp(0, Location::RegisterLocation(R13));
     summary->set_out(Location::FpuRegisterLocation(XMM1));
     return summary;
   }
+  ASSERT(kind() == MethodRecognizer::kMathSqrt);
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
   LocationSummary* summary =
       new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
   summary->set_in(0, Location::RequiresFpuRegister());
   summary->set_out(Location::RequiresFpuRegister());
   return summary;
 }
 
 
 void MathUnaryInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   if (kind() == MethodRecognizer::kMathSqrt) {
     __ sqrtsd(locs()->out().fpu_reg(), locs()->in(0).fpu_reg());
   } else {
-    __ EnterFrame(0);
+    ASSERT((kind() == MethodRecognizer::kMathSin) ||
+           (kind() == MethodRecognizer::kMathCos));
+    // Save RSP.
+    __ movq(locs()->temp(0).reg(), RSP);
     __ ReserveAlignedFrameSpace(0);
     __ movaps(XMM0, locs()->in(0).fpu_reg());
     __ CallRuntime(TargetFunction(), InputCount());
     __ movaps(locs()->out().fpu_reg(), XMM0);
-    __ leave();
+    // Restore RSP.
+    __ movq(RSP, locs()->temp(0).reg());
   }
 }
 
 
 LocationSummary* UnarySmiOpInstr::MakeLocationSummary(bool opt) const {
   const intptr_t kNumInputs = 1;
   return LocationSummary::Make(kNumInputs,
                                Location::SameAsFirstInput(),
                                LocationSummary::kNoCall);
 }
@@ skipping 295 matching lines @@
 }
 
 
 LocationSummary* InvokeMathCFunctionInstr::MakeLocationSummary(bool opt) const {
   // Calling convention on x64 uses XMM0 and XMM1 to pass the first two
   // double arguments and XMM0 to return the result. Unfortunately
   // currently we can't specify these registers because ParallelMoveResolver
   // assumes that XMM0 is free at all times.
   // TODO(vegorov): allow XMM0 to be used.
   ASSERT((InputCount() == 1) || (InputCount() == 2));
-  const intptr_t kNumTemps = 0;
+  const intptr_t kNumTemps = 1;
   LocationSummary* result =
       new LocationSummary(InputCount(), kNumTemps, LocationSummary::kCall);
+  result->set_temp(0, Location::RegisterLocation(R13));
   result->set_in(0, Location::FpuRegisterLocation(XMM2));
   if (InputCount() == 2) {
     result->set_in(1, Location::FpuRegisterLocation(XMM1));
   }
   if (recognized_kind() == MethodRecognizer::kMathDoublePow) {
+    // Temp index 1.
     result->AddTemp(Location::RegisterLocation(RAX));
+    // Temp index 2.
     result->AddTemp(Location::FpuRegisterLocation(XMM4));
   }
   result->set_out(Location::FpuRegisterLocation(XMM3));
   return result;
 }
 
 
 void InvokeMathCFunctionInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  __ EnterFrame(0);
+  // Save RSP.
+  __ movq(locs()->temp(kSavedSpTempIndex).reg(), RSP);
   __ ReserveAlignedFrameSpace(0);
   __ movaps(XMM0, locs()->in(0).fpu_reg());
   if (InputCount() == 2) {
     ASSERT(locs()->in(1).fpu_reg() == XMM1);
   }
   // For pow-function return NaN if exponent is NaN.
   Label do_call, skip_call;
   if (recognized_kind() == MethodRecognizer::kMathDoublePow) {
     // Pseudo code:
     // if (exponent == 0.0) return 0.0;
     // if (base == 1.0) return 1.0;
     // if (base.isNaN || exponent.isNaN) {
     //    return double.NAN;
     // }
     XmmRegister base = locs()->in(0).fpu_reg();
     XmmRegister exp = locs()->in(1).fpu_reg();
     XmmRegister result = locs()->out().fpu_reg();
-    Register temp = locs()->temp(0).reg();
-    XmmRegister zero_temp = locs()->temp(1).fpu_reg();
+    Register temp = locs()->temp(kObjectTempIndex).reg();
+    XmmRegister zero_temp = locs()->temp(kDoubleTempIndex).fpu_reg();
 
     // Check if exponent is 0.0 -> return 1.0;
     __ LoadObject(temp, Double::ZoneHandle(Double::NewCanonical(0)), PP);
     __ movsd(zero_temp, FieldAddress(temp, Double::value_offset()));
     __ LoadObject(temp, Double::ZoneHandle(Double::NewCanonical(1)), PP);
     __ movsd(result, FieldAddress(temp, Double::value_offset()));
     // 'result' contains 1.0.
     Label exp_is_nan;
     __ comisd(exp, zero_temp);
     __ j(PARITY_EVEN, &exp_is_nan, Assembler::kNearJump);  // NaN.
@@ skipping 16 matching lines @@
     __ comisd(base, result);
     __ j(PARITY_EVEN, &base_is_nan, Assembler::kNearJump);
     __ j(EQUAL, &skip_call, Assembler::kNearJump);  // base and result are 1.0
     __ movsd(result, exp);  // result is NaN
     __ jmp(&skip_call, Assembler::kNearJump);
   }
   __ Bind(&do_call);
   __ CallRuntime(TargetFunction(), InputCount());
   __ movaps(locs()->out().fpu_reg(), XMM0);
   __ Bind(&skip_call);
-  __ leave();
+  // Restore RSP.
+  __ movq(RSP, locs()->temp(kSavedSpTempIndex).reg());
 }
 
 
 LocationSummary* MergedMathInstr::MakeLocationSummary(bool opt) const {
   if (kind() == MergedMathInstr::kTruncDivMod) {
     const intptr_t kNumInputs = 2;
     const intptr_t kNumTemps = 1;
     LocationSummary* summary =
         new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kNoCall);
     // Both inputs must be writable because they will be untagged.
     summary->set_in(0, Location::RegisterLocation(RAX));
     summary->set_in(1, Location::WritableRegister());
     summary->set_out(Location::RequiresRegister());
     // Will be used for sign extension and division.
     summary->set_temp(0, Location::RegisterLocation(RDX));
     return summary;
   }
   if (kind() == MergedMathInstr::kSinCos) {
     const intptr_t kNumInputs = 1;
-    const intptr_t kNumTemps = 0;
+    const intptr_t kNumTemps = 1;
     LocationSummary* summary =
         new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kCall);
     summary->set_in(0, Location::FpuRegisterLocation(XMM1));
+    // R13 is chosen because it is callee saved so we do not need to back it
+    // up before calling into the runtime.
+    summary->set_temp(0, Location::RegisterLocation(R13));
     summary->set_out(Location::RegisterLocation(RAX));
     return summary;
   }
   UNIMPLEMENTED();
   return NULL;
 }
 
 
 
 typedef void (*SinCosCFunction) (double x, double* res_sin, double* res_cos);
@@ skipping 102 matching lines @@
     __ SmiTag(RAX);
     __ SmiTag(RDX);
     __ StoreIntoObjectNoBarrier(result, trunc_div_address, RAX);
     __ StoreIntoObjectNoBarrier(result, mod_address, RDX);
     // FLAG_throw_on_javascript_int_overflow: not needed.
     // Note that the result of an integer division/modulo of two
     // in-range arguments, cannot create out-of-range result.
     return;
   }
   if (kind() == MergedMathInstr::kSinCos) {
-    __ EnterFrame(0);
+    // Save RSP.
+    __ movq(locs()->temp(0).reg(), RSP);
     // +-------------------------------+
     // | double-argument               |  <- TOS
     // +-------------------------------+
     // | address-cos-result            |  +8
     // +-------------------------------+
     // | address-sin-result            |  +16
     // +-------------------------------+
     // | double-storage-for-cos-result |  +24
     // +-------------------------------+
     // | double-storage-for-sin-result |  +32
     // +-------------------------------+
     // ....
     __ ReserveAlignedFrameSpace(kDoubleSize * 3 + kWordSize * 2);
     __ movsd(Address(RSP, 0), locs()->in(0).fpu_reg());
 
     __ leaq(RDI, Address(RSP, 2 * kWordSize + kDoubleSize));
     __ leaq(RSI, Address(RSP, 2 * kWordSize + 2 * kDoubleSize));
     __ movaps(XMM0, locs()->in(0).fpu_reg());
 
     __ CallRuntime(kSinCosRuntimeEntry, InputCount());
     __ movsd(XMM0, Address(RSP, 2 * kWordSize + kDoubleSize * 2));  // sin.
     __ movsd(XMM1, Address(RSP, 2 * kWordSize + kDoubleSize));  // cos.
-    __ leave();
+    // Restore RSP.
+    __ movq(RSP, locs()->temp(0).reg());
 
     Register result = locs()->out().reg();
     const TypedData& res_array = TypedData::ZoneHandle(
       TypedData::New(kTypedDataFloat64ArrayCid, 2, Heap::kOld));
     __ LoadObject(result, res_array, PP);
     const intptr_t index_scale =
         FlowGraphCompiler::ElementSizeFor(kTypedDataFloat64ArrayCid);
     Address sin_address(
         FlowGraphCompiler::ElementAddressForIntIndex(
             kTypedDataFloat64ArrayCid, index_scale, result,
@@ skipping 493 matching lines @@
                          PcDescriptors::kOther,
                          locs());
   __ Drop(ArgumentCount());  // Discard arguments.
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64