V4 JIT: support saving used callee saved FP registers.

This is not used yet by any platform/abi we support, because we do not
define any callee-saved FP registers. Yet.

Change-Id: I5857a452456175398c5e9681ff33800b9431b9da
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

4 files changed, 46 insertions, 21 deletions

diff --git a/src/qml/jit/qv4assembler.cpp b/src/qml/jit/qv4assembler.cpp
index e76d498409..130a673484 100644
--- a/src/qml/jit/qv4assembler.cpp
+++ b/src/qml/jit/qv4assembler.cpp
@@ -239,37 +239,50 @@ void Assembler::storeValue(QV4::Primitive value, IR::Expr *destination)
     storeValue(value, addr);
 }
 
-void Assembler::enterStandardStackFrame(const RegisterInformation &regularRegistersToSave)
+void Assembler::enterStandardStackFrame(const RegisterInformation &regularRegistersToSave,
+                                        const RegisterInformation &fpRegistersToSave)
 {
     platformEnterStandardStackFrame(this);
 
-    // ### FIXME: Handle through calleeSavedRegisters mechanism
-    // or eliminate StackFrameRegister altogether.
     push(StackFrameRegister);
     move(StackPointerRegister, StackFrameRegister);
 
-    int frameSize = _stackLayout->calculateStackFrameSize();
-
+    const int frameSize = _stackLayout->calculateStackFrameSize();
     subPtr(TrustedImm32(frameSize), StackPointerRegister);
 
-    Address slotAddr(StackFrameRegister, -RegisterSize);
+    Address slotAddr(StackFrameRegister, 0);
     for (int i = 0, ei = regularRegistersToSave.size(); i < ei; ++i) {
-        storePtr(regularRegistersToSave.at(i).reg<RegisterID>(), slotAddr);
+        Q_ASSERT(regularRegistersToSave.at(i).isRegularRegister());
         slotAddr.offset -= RegisterSize;
+        storePtr(regularRegistersToSave.at(i).reg<RegisterID>(), slotAddr);
+    }
+    for (int i = 0, ei = fpRegistersToSave.size(); i < ei; ++i) {
+        Q_ASSERT(fpRegistersToSave.at(i).isFloatingPoint());
+        slotAddr.offset -= sizeof(double);
+        JSC::MacroAssembler::storeDouble(fpRegistersToSave.at(i).reg<FPRegisterID>(), slotAddr);
     }
 }
 
-void Assembler::leaveStandardStackFrame(const RegisterInformation &regularRegistersToSave)
+void Assembler::leaveStandardStackFrame(const RegisterInformation &regularRegistersToSave,
+                                        const RegisterInformation &fpRegistersToSave)
 {
-    Address slotAddr(StackFrameRegister, -regularRegistersToSave.size() * RegisterSize);
+    Address slotAddr(StackFrameRegister, -regularRegistersToSave.size() * RegisterSize - fpRegistersToSave.size() * sizeof(double));
 
     // restore the callee saved registers
+    for (int i = fpRegistersToSave.size() - 1; i >= 0; --i) {
+        Q_ASSERT(fpRegistersToSave.at(i).isFloatingPoint());
+        JSC::MacroAssembler::loadDouble(slotAddr, fpRegistersToSave.at(i).reg<FPRegisterID>());
+        slotAddr.offset += sizeof(double);
+    }
     for (int i = regularRegistersToSave.size() - 1; i >= 0; --i) {
+        Q_ASSERT(regularRegistersToSave.at(i).isRegularRegister());
         loadPtr(slotAddr, regularRegistersToSave.at(i).reg<RegisterID>());
         slotAddr.offset += RegisterSize;
     }
 
-    int frameSize = _stackLayout->calculateStackFrameSize();
+    Q_ASSERT(slotAddr.offset == 0);
+
+    const int frameSize = _stackLayout->calculateStackFrameSize();
     // Work around bug in ARMv7Assembler.h where add32(imm, sp, sp) doesn't
     // work well for large immediates.
 #if CPU(ARM_THUMB2)
@@ -390,9 +403,9 @@ Assembler::Jump Assembler::branchInt32(bool invertCondition, IR::AluOp op, IR::E
                                          toInt32Register(right, Assembler::ReturnValueRegister));
 }
 
-void Assembler::setStackLayout(int maxArgCountForBuiltins, int regularRegistersToSave)
+void Assembler::setStackLayout(int maxArgCountForBuiltins, int regularRegistersToSave, int fpRegistersToSave)
 {
-    _stackLayout.reset(new StackLayout(_function, maxArgCountForBuiltins, regularRegistersToSave));
+    _stackLayout.reset(new StackLayout(_function, maxArgCountForBuiltins, regularRegistersToSave, fpRegistersToSave));
 }
 
 #endif
diff --git a/src/qml/jit/qv4assembler_p.h b/src/qml/jit/qv4assembler_p.h
index 7d774f93f7..8f50610072 100644
--- a/src/qml/jit/qv4assembler_p.h
+++ b/src/qml/jit/qv4assembler_p.h
@@ -182,8 +182,9 @@ public:
     class StackLayout
     {
     public:
-        StackLayout(IR::Function *function, int maxArgCountForBuiltins, int normalRegistersToSave)
+        StackLayout(IR::Function *function, int maxArgCountForBuiltins, int normalRegistersToSave, int fpRegistersToSave)
             : normalRegistersToSave(normalRegistersToSave)
+            , fpRegistersToSave(fpRegistersToSave)
             , maxOutgoingArgumentCount(function->maxNumberOfArguments)
             , localCount(function->tempCount)
             , savedRegCount(maxArgCountForBuiltins)
@@ -216,7 +217,7 @@ public:
                                                      + RegisterSize; // saved StackFrameRegister
 
             // space for the callee saved registers
-            int frameSize = RegisterSize * normalRegistersToSave;
+            int frameSize = RegisterSize * normalRegistersToSave + sizeof(double) * fpRegistersToSave;
             frameSize += savedRegCount * sizeof(QV4::Value); // these get written out as Values, not as native registers
 
             Q_ASSERT(frameSize + stackSpaceAllocatedOtherwise < INT_MAX);
@@ -269,11 +270,13 @@ public:
         int calleeSavedRegisterSpace() const
         {
             // plus 1 for the old FP
-            return RegisterSize * (normalRegistersToSave + 1);
+            return RegisterSize * (normalRegistersToSave + 1)
+                    + sizeof(double) * fpRegistersToSave;
         }
 
     private:
         int normalRegistersToSave;
+        int fpRegistersToSave;
 
         /// arg count for calls to JS functions
         int maxOutgoingArgumentCount;
@@ -794,8 +797,10 @@ public:
 
     void storeValue(QV4::Primitive value, IR::Expr* temp);
 
-    void enterStandardStackFrame(const RegisterInformation &regularRegistersToSave);
-    void leaveStandardStackFrame(const RegisterInformation &regularRegistersToSave);
+    void enterStandardStackFrame(const RegisterInformation &regularRegistersToSave,
+                                 const RegisterInformation &fpRegistersToSave);
+    void leaveStandardStackFrame(const RegisterInformation &regularRegistersToSave,
+                                 const RegisterInformation &fpRegistersToSave);
 
     void checkException() {
         loadPtr(Address(ContextRegister, qOffsetOf(QV4::ExecutionContext::Data, engine)), ScratchRegister);
@@ -1146,7 +1151,7 @@ public:
 
     JSC::MacroAssemblerCodeRef link(int *codeSize);
 
-    void setStackLayout(int maxArgCountForBuiltins, int regularRegistersToSave);
+    void setStackLayout(int maxArgCountForBuiltins, int regularRegistersToSave, int fpRegistersToSave);
     const StackLayout &stackLayout() const { return *_stackLayout.data(); }
     ConstantTable &constantTable() { return _constTable; }
 
diff --git a/src/qml/jit/qv4isel_masm.cpp b/src/qml/jit/qv4isel_masm.cpp
index 39e7c0fbc2..104cd2e903 100644
--- a/src/qml/jit/qv4isel_masm.cpp
+++ b/src/qml/jit/qv4isel_masm.cpp
@@ -242,8 +242,9 @@ void InstructionSelection::run(int functionIndex)
     Assembler* oldAssembler = _as;
     _as = new Assembler(this, _function, executableAllocator);
     _as->setStackLayout(6, // 6 == max argc for calls to built-ins with an argument array
-                        regularRegistersToSave.size());
-    _as->enterStandardStackFrame(regularRegistersToSave);
+                        regularRegistersToSave.size(),
+                        fpRegistersToSave.size());
+    _as->enterStandardStackFrame(regularRegistersToSave, fpRegistersToSave);
 
 #ifdef ARGUMENTS_IN_REGISTERS
     _as->move(_as->registerForArgument(0), Assembler::ContextRegister);
@@ -1474,7 +1475,7 @@ void InstructionSelection::visitRet(IR::Ret *s)
     _as->loadPtr(Address(Assembler::ContextRegister, qOffsetOf(ExecutionContext::Data, engine)), Assembler::ScratchRegister);
     _as->storePtr(Assembler::LocalsRegister, Address(Assembler::ScratchRegister, qOffsetOf(ExecutionEngine, jsStackTop)));
 
-    _as->leaveStandardStackFrame(regularRegistersToSave);
+    _as->leaveStandardStackFrame(regularRegistersToSave, fpRegistersToSave);
     _as->ret();
 }
 
@@ -1532,6 +1533,7 @@ int InstructionSelection::prepareCallData(IR::ExprList* args, IR::Expr *thisObje
 void InstructionSelection::calculateRegistersToSave(const RegisterInformation &used)
 {
     regularRegistersToSave.clear();
+    fpRegistersToSave.clear();
 
     foreach (const RegisterInfo &ri, Assembler::getRegisterInfo()) {
         if (ri.isCallerSaved())
@@ -1546,6 +1548,10 @@ void InstructionSelection::calculateRegistersToSave(const RegisterInformation &u
 #endif // RESTORE_EBX_ON_CALL
             if (ri.isPredefined() || used.contains(ri))
                 regularRegistersToSave.append(ri);
+        } else {
+            Q_ASSERT(ri.isFloatingPoint());
+            if (ri.isPredefined() || used.contains(ri))
+                fpRegistersToSave.append(ri);
         }
     }
 }
diff --git a/src/qml/jit/qv4isel_masm_p.h b/src/qml/jit/qv4isel_masm_p.h
index bbe0f05556..264ad2d179 100644
--- a/src/qml/jit/qv4isel_masm_p.h
+++ b/src/qml/jit/qv4isel_masm_p.h
@@ -266,6 +266,7 @@ private:
     QScopedPointer<CompilationUnit> compilationUnit;
     QQmlEnginePrivate *qmlEngine;
     RegisterInformation regularRegistersToSave;
+    RegisterInformation fpRegistersToSave;
 };
 
 class Q_QML_EXPORT ISelFactory: public EvalISelFactory