V4: clean-up target specific register definitions and stack usage

All constants referring to registers and all constants and functions
that do platform specific things with the stack, are all modev into a
separate file. Information about how a specific platform register is
used by the ABI is also extended and is now captured in the RegisterInfo
class. Usage of this information will be extended in subsequent patches.

This also fix ARM register usage:
- Correct fp register for Thumb mode.
- Only push registers that have to be saved and will actually be used
  from the stack (i.e. do not push r0-r3 in the function prelude).

Change-Id: Ia372505ade8f2648595c7aec1d281955392f34a1
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

1 files changed, 7 insertions, 154 deletions

diff --git a/src/qml/jit/qv4assembler_p.h b/src/qml/jit/qv4assembler_p.h
index 90387dcf79..faef4fd168 100644
--- a/src/qml/jit/qv4assembler_p.h
+++ b/src/qml/jit/qv4assembler_p.h
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/legal
 **
 ** This file is part of the QtQml module of the Qt Toolkit.
@@ -47,6 +47,7 @@
 #include "private/qv4isel_util_p.h"
 #include "private/qv4value_p.h"
 #include "private/qv4lookup_p.h"
+#include "qv4targetplatform_p.h"
 
 #include <QtCore/QHash>
 #include <QtCore/QStack>
@@ -123,158 +124,12 @@ struct ExceptionCheck<void (*)(QV4::NoThrowContext *, A, B, C)> {
     enum { NeedsCheck = 0 };
 };
 
-class Assembler : public JSC::MacroAssembler
+class Assembler : public JSC::MacroAssembler, public TargetPlatform
 {
 public:
     Assembler(InstructionSelection *isel, IR::Function* function, QV4::ExecutableAllocator *executableAllocator,
               int maxArgCountForBuiltins);
 
-#if CPU(X86)
-
-#undef VALUE_FITS_IN_REGISTER
-#undef ARGUMENTS_IN_REGISTERS
-
-#define HAVE_ALU_OPS_WITH_MEM_OPERAND 1
-
-    static const RegisterID StackFrameRegister = JSC::X86Registers::ebp;
-    static const RegisterID StackPointerRegister = JSC::X86Registers::esp;
-    static const RegisterID LocalsRegister = JSC::X86Registers::edi;
-    static const RegisterID ContextRegister = JSC::X86Registers::esi;
-    static const RegisterID ReturnValueRegister = JSC::X86Registers::eax;
-    static const RegisterID ScratchRegister = JSC::X86Registers::ecx;
-    static const FPRegisterID FPGpr0 = JSC::X86Registers::xmm0;
-    static const FPRegisterID FPGpr1 = JSC::X86Registers::xmm1;
-
-    static const int RegisterSize = 4;
-
-    static const int RegisterArgumentCount = 0;
-    static RegisterID registerForArgument(int)
-    {
-        Q_ASSERT(false);
-        // Not reached.
-        return JSC::X86Registers::eax;
-    }
-
-    // Return address is pushed onto stack by the CPU.
-    static const int StackSpaceAllocatedUponFunctionEntry = RegisterSize;
-    static const int StackShadowSpace = 0;
-    inline void platformEnterStandardStackFrame() {}
-    inline void platformLeaveStandardStackFrame() {}
-#elif CPU(X86_64)
-
-#define VALUE_FITS_IN_REGISTER
-#define ARGUMENTS_IN_REGISTERS
-#define HAVE_ALU_OPS_WITH_MEM_OPERAND 1
-
-    static const RegisterID StackFrameRegister = JSC::X86Registers::ebp;
-    static const RegisterID StackPointerRegister = JSC::X86Registers::esp;
-    static const RegisterID LocalsRegister = JSC::X86Registers::r12;
-    static const RegisterID ContextRegister = JSC::X86Registers::r14;
-    static const RegisterID ReturnValueRegister = JSC::X86Registers::eax;
-    static const RegisterID ScratchRegister = JSC::X86Registers::r10;
-    static const FPRegisterID FPGpr0 = JSC::X86Registers::xmm0;
-    static const FPRegisterID FPGpr1 = JSC::X86Registers::xmm1;
-
-    static const int RegisterSize = 8;
-
-#if OS(WINDOWS)
-    static const int RegisterArgumentCount = 4;
-    static RegisterID registerForArgument(int index)
-    {
-        static RegisterID regs[RegisterArgumentCount] = {
-            JSC::X86Registers::ecx,
-            JSC::X86Registers::edx,
-            JSC::X86Registers::r8,
-            JSC::X86Registers::r9
-        };
-        Q_ASSERT(index >= 0 && index < RegisterArgumentCount);
-        return regs[index];
-    };
-    static const int StackShadowSpace = 32;
-#else // Unix
-    static const int RegisterArgumentCount = 6;
-    static RegisterID registerForArgument(int index)
-    {
-        static RegisterID regs[RegisterArgumentCount] = {
-            JSC::X86Registers::edi,
-            JSC::X86Registers::esi,
-            JSC::X86Registers::edx,
-            JSC::X86Registers::ecx,
-            JSC::X86Registers::r8,
-            JSC::X86Registers::r9
-        };
-        Q_ASSERT(index >= 0 && index < RegisterArgumentCount);
-        return regs[index];
-    };
-    static const int StackShadowSpace = 0;
-#endif
-
-    // Return address is pushed onto stack by the CPU.
-    static const int StackSpaceAllocatedUponFunctionEntry = RegisterSize;
-    inline void platformEnterStandardStackFrame() {}
-    inline void platformLeaveStandardStackFrame() {}
-#elif CPU(ARM)
-
-#undef VALUE_FITS_IN_REGISTER
-#define ARGUMENTS_IN_REGISTERS
-#undef HAVE_ALU_OPS_WITH_MEM_OPERAND
-
-    static const RegisterID StackPointerRegister = JSC::ARMRegisters::sp; // r13
-    static const RegisterID StackFrameRegister = JSC::ARMRegisters::fp; // r11
-    static const RegisterID LocalsRegister = JSC::ARMRegisters::r7;
-    static const RegisterID ScratchRegister = JSC::ARMRegisters::r6;
-    static const RegisterID ContextRegister = JSC::ARMRegisters::r5;
-    static const RegisterID ReturnValueRegister = JSC::ARMRegisters::r0;
-    static const FPRegisterID FPGpr0 = JSC::ARMRegisters::d0;
-    static const FPRegisterID FPGpr1 = JSC::ARMRegisters::d1;
-
-    static const int RegisterSize = 4;
-
-    static const RegisterID RegisterArgument1 = JSC::ARMRegisters::r0;
-    static const RegisterID RegisterArgument2 = JSC::ARMRegisters::r1;
-    static const RegisterID RegisterArgument3 = JSC::ARMRegisters::r2;
-    static const RegisterID RegisterArgument4 = JSC::ARMRegisters::r3;
-
-    static const int RegisterArgumentCount = 4;
-    static RegisterID registerForArgument(int index)
-    {
-        Q_ASSERT(index >= 0 && index < RegisterArgumentCount);
-        return static_cast<RegisterID>(JSC::ARMRegisters::r0 + index);
-    };
-
-    // Registers saved in platformEnterStandardStackFrame below.
-    static const int StackSpaceAllocatedUponFunctionEntry = 5 * RegisterSize;
-    static const int StackShadowSpace = 0;
-    inline void platformEnterStandardStackFrame()
-    {
-        // Move the register arguments onto the stack as if they were
-        // pushed by the caller, just like on ia32. This gives us consistent
-        // access to the parameters if we need to.
-        push(JSC::ARMRegisters::r3);
-        push(JSC::ARMRegisters::r2);
-        push(JSC::ARMRegisters::r1);
-        push(JSC::ARMRegisters::r0);
-        push(JSC::ARMRegisters::lr);
-    }
-    inline void platformLeaveStandardStackFrame()
-    {
-        pop(JSC::ARMRegisters::lr);
-        addPtr(TrustedImm32(4 * RegisterSize), StackPointerRegister);
-    }
-#else
-#error The JIT needs to be ported to this platform.
-#endif
-    static const int calleeSavedRegisterCount;
-
-#if CPU(X86) || CPU(X86_64)
-    static const int StackAlignment = 16;
-#elif CPU(ARM)
-    // Per AAPCS
-    static const int StackAlignment = 8;
-#else
-#error Stack alignment unknown for this platform.
-#endif
-
     // Explicit type to allow distinguishing between
     // pushing an address itself or the value it points
     // to onto the stack when calling functions.
@@ -318,7 +173,7 @@ public:
     {
     public:
         StackLayout(IR::Function *function, int maxArgCountForBuiltins)
-            : calleeSavedRegCount(Assembler::calleeSavedRegisterCount + 1)
+            : calleeSavedRegCount(Assembler::calleeSavedRegisterCount() + 1)
             , maxOutgoingArgumentCount(function->maxNumberOfArguments)
             , localCount(function->tempCount)
             , savedRegCount(maxArgCountForBuiltins)
@@ -351,7 +206,7 @@ public:
                                                      + RegisterSize; // saved StackFrameRegister
 
             // space for the callee saved registers
-            int frameSize = RegisterSize * calleeSavedRegisterCount;
+            int frameSize = RegisterSize * calleeSavedRegisterCount();
             frameSize += savedRegCount * sizeof(QV4::Value); // these get written out as Values, not as native registers
 
             Q_ASSERT(frameSize + stackSpaceAllocatedOtherwise < INT_MAX);
@@ -1014,10 +869,8 @@ public:
         prepareRelativeCall(function, this);
         loadArgumentOnStackOrRegister<0>(arg1);
 
-#if (OS(LINUX) && CPU(X86) && (defined(__PIC__) || defined(__PIE__))) || \
-    (OS(WINDOWS) && CPU(X86))
-        load32(Address(StackFrameRegister, -int(sizeof(void*))),
-               JSC::X86Registers::ebx); // restore the GOT ptr
+#ifdef RESTORE_EBX_ON_CALL
+        load32(ebxAddressOnStack(), JSC::X86Registers::ebx); // restore the GOT ptr
 #endif
 
         callAbsolute(functionName, function);