Stop creating dummy call frames when calling out to C functions

runtime/vm/intermediate_language_ia32.cc

Index: runtime/vm/intermediate_language_ia32.cc
diff --git a/runtime/vm/intermediate_language_ia32.cc b/runtime/vm/intermediate_language_ia32.cc
index 369d154f976867657a33cb0c6eb61a11c570ab77..f1248a215db4735154121b1620db5fde513b0802 100644
--- a/runtime/vm/intermediate_language_ia32.cc
+++ b/runtime/vm/intermediate_language_ia32.cc
@@ -3981,13 +3981,17 @@ LocationSummary* MathUnaryInstr::MakeLocationSummary(bool opt) const {
   if ((kind() == MethodRecognizer::kMathSin) ||
       (kind() == MethodRecognizer::kMathCos)) {
     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));
+    // EDI 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(EDI));
     summary->set_out(Location::FpuRegisterLocation(XMM1));
     return summary;
   }
+  ASSERT(kind() == MethodRecognizer::kMathSqrt);
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
   LocationSummary* summary =
@@ -4002,13 +4006,17 @@ 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 ESP.
+    __ movl(locs()->temp(0).reg(), ESP);
     __ ReserveAlignedFrameSpace(kDoubleSize * InputCount());
     __ movsd(Address(ESP, 0), locs()->in(0).fpu_reg());
     __ CallRuntime(TargetFunction(), InputCount());
     __ fstpl(Address(ESP, 0));
     __ movsd(locs()->out().fpu_reg(), Address(ESP, 0));
-    __ leave();
+    // Restore ESP.
+    __ movl(ESP, locs()->temp(0).reg());
   }
 }
 
@@ -4298,15 +4306,20 @@ void FloatToDoubleInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
 
 LocationSummary* InvokeMathCFunctionInstr::MakeLocationSummary(bool opt) const {
   ASSERT((InputCount() == 1) || (InputCount() == 2));
-  const intptr_t kNumTemps = 0;
+  const intptr_t kNumTemps = 1;
   LocationSummary* result =
       new LocationSummary(InputCount(), kNumTemps, LocationSummary::kCall);
+  // EDI is chosen because it is callee saved so we do not need to back it
+  // up before calling into the runtime.
+  result->set_temp(0, Location::RegisterLocation(EDI));
   result->set_in(0, Location::FpuRegisterLocation(XMM1));
   if (InputCount() == 2) {
     result->set_in(1, Location::FpuRegisterLocation(XMM2));
   }
   if (recognized_kind() == MethodRecognizer::kMathDoublePow) {
+    // Temp index 1.
     result->AddTemp(Location::RegisterLocation(EAX));
+    // Temp index 2.
     result->AddTemp(Location::FpuRegisterLocation(XMM4));
   }
   result->set_out(Location::FpuRegisterLocation(XMM3));
@@ -4315,7 +4328,8 @@ LocationSummary* InvokeMathCFunctionInstr::MakeLocationSummary(bool opt) const {
 
 
 void InvokeMathCFunctionInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  __ EnterFrame(0);
+  // Save ESP.
+  __ movl(locs()->temp(kSavedSpTempIndex).reg(), ESP);
   __ ReserveAlignedFrameSpace(kDoubleSize * InputCount());
   for (intptr_t i = 0; i < InputCount(); i++) {
     __ movsd(Address(ESP, kDoubleSize * i), locs()->in(i).fpu_reg());
@@ -4331,8 +4345,8 @@ void InvokeMathCFunctionInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
     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();
 
     Label check_base_is_one;
     // Check if exponent is 0.0 -> return 1.0;
@@ -4363,7 +4377,8 @@ void InvokeMathCFunctionInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   __ fstpl(Address(ESP, 0));
   __ movsd(locs()->out().fpu_reg(), Address(ESP, 0));
   __ Bind(&skip_call);
-  __ leave();
+  // Restore ESP.
+  __ movl(ESP, locs()->temp(kSavedSpTempIndex).reg());
 }