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lclvars.cpp
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lclvars.cpp
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
/*XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XX XX
XX LclVarsInfo XX
XX XX
XX The variables to be used by the code generator. XX
XX XX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
*/
#include "jitpch.h"
#ifdef _MSC_VER
#pragma hdrstop
#endif
#include "emit.h"
#include "register_arg_convention.h"
/*****************************************************************************/
#ifdef DEBUG
#if DOUBLE_ALIGN
/* static */
unsigned Compiler::s_lvaDoubleAlignedProcsCount = 0;
#endif
#endif
/*****************************************************************************/
void Compiler::lvaInit()
{
/* We haven't allocated stack variables yet */
lvaRefCountingStarted = false;
lvaLocalVarRefCounted = false;
lvaGenericsContextUseCount = 0;
lvaSortAgain = false; // false: We don't need to call lvaSortOnly()
lvaTrackedFixed = false; // false: We can still add new tracked variables
lvaDoneFrameLayout = NO_FRAME_LAYOUT;
#if !FEATURE_EH_FUNCLETS
lvaShadowSPslotsVar = BAD_VAR_NUM;
#endif // !FEATURE_EH_FUNCLETS
lvaInlinedPInvokeFrameVar = BAD_VAR_NUM;
lvaReversePInvokeFrameVar = BAD_VAR_NUM;
#if FEATURE_FIXED_OUT_ARGS
lvaPInvokeFrameRegSaveVar = BAD_VAR_NUM;
lvaOutgoingArgSpaceVar = BAD_VAR_NUM;
lvaOutgoingArgSpaceSize = PhasedVar<unsigned>();
#endif // FEATURE_FIXED_OUT_ARGS
#ifdef _TARGET_ARM_
lvaPromotedStructAssemblyScratchVar = BAD_VAR_NUM;
#endif // _TARGET_ARM_
lvaLocAllocSPvar = BAD_VAR_NUM;
lvaNewObjArrayArgs = BAD_VAR_NUM;
lvaGSSecurityCookie = BAD_VAR_NUM;
#ifdef _TARGET_X86_
lvaVarargsBaseOfStkArgs = BAD_VAR_NUM;
#endif // _TARGET_X86_
lvaVarargsHandleArg = BAD_VAR_NUM;
lvaSecurityObject = BAD_VAR_NUM;
lvaStubArgumentVar = BAD_VAR_NUM;
lvaArg0Var = BAD_VAR_NUM;
lvaMonAcquired = BAD_VAR_NUM;
lvaInlineeReturnSpillTemp = BAD_VAR_NUM;
gsShadowVarInfo = nullptr;
#if FEATURE_EH_FUNCLETS
lvaPSPSym = BAD_VAR_NUM;
#endif
#if FEATURE_SIMD
lvaSIMDInitTempVarNum = BAD_VAR_NUM;
#endif // FEATURE_SIMD
lvaCurEpoch = 0;
#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
lvaFirstStackIncomingArgNum = BAD_VAR_NUM;
#endif // !FEATURE_UNIX_AMD64_STRUCT_PASSING
}
/*****************************************************************************/
void Compiler::lvaInitTypeRef()
{
/* x86 args look something like this:
[this ptr] [hidden return buffer] [declared arguments]* [generic context] [var arg cookie]
x64 is closer to the native ABI:
[this ptr] [hidden return buffer] [generic context] [var arg cookie] [declared arguments]*
(Note: prior to .NET Framework 4.5.1 for Windows 8.1 (but not .NET Framework 4.5.1 "downlevel"),
the "hidden return buffer" came before the "this ptr". Now, the "this ptr" comes first. This
is different from the C++ order, where the "hidden return buffer" always comes first.)
ARM and ARM64 are the same as the current x64 convention:
[this ptr] [hidden return buffer] [generic context] [var arg cookie] [declared arguments]*
Key difference:
The var arg cookie and generic context are swapped with respect to the user arguments
*/
/* Set compArgsCount and compLocalsCount */
info.compArgsCount = info.compMethodInfo->args.numArgs;
// Is there a 'this' pointer
if (!info.compIsStatic)
{
info.compArgsCount++;
}
else
{
info.compThisArg = BAD_VAR_NUM;
}
info.compILargsCount = info.compArgsCount;
#ifdef FEATURE_SIMD
if (featureSIMD && (info.compRetNativeType == TYP_STRUCT))
{
var_types structType = impNormStructType(info.compMethodInfo->args.retTypeClass);
info.compRetType = structType;
}
#endif // FEATURE_SIMD
// Are we returning a struct using a return buffer argument?
//
const bool hasRetBuffArg = impMethodInfo_hasRetBuffArg(info.compMethodInfo);
// Possibly change the compRetNativeType from TYP_STRUCT to a "primitive" type
// when we are returning a struct by value and it fits in one register
//
if (!hasRetBuffArg && varTypeIsStruct(info.compRetNativeType))
{
CORINFO_CLASS_HANDLE retClsHnd = info.compMethodInfo->args.retTypeClass;
Compiler::structPassingKind howToReturnStruct;
var_types returnType = getReturnTypeForStruct(retClsHnd, &howToReturnStruct);
if (howToReturnStruct == SPK_PrimitiveType)
{
assert(returnType != TYP_UNKNOWN);
assert(!varTypeIsStruct(returnType));
info.compRetNativeType = returnType;
// ToDo: Refactor this common code sequence into its own method as it is used 4+ times
if ((returnType == TYP_LONG) && (compLongUsed == false))
{
compLongUsed = true;
}
else if (((returnType == TYP_FLOAT) || (returnType == TYP_DOUBLE)) && (compFloatingPointUsed == false))
{
compFloatingPointUsed = true;
}
}
}
// Do we have a RetBuffArg?
if (hasRetBuffArg)
{
info.compArgsCount++;
}
else
{
info.compRetBuffArg = BAD_VAR_NUM;
}
/* There is a 'hidden' cookie pushed last when the
calling convention is varargs */
if (info.compIsVarArgs)
{
info.compArgsCount++;
}
// Is there an extra parameter used to pass instantiation info to
// shared generic methods and shared generic struct instance methods?
if (info.compMethodInfo->args.callConv & CORINFO_CALLCONV_PARAMTYPE)
{
info.compArgsCount++;
}
else
{
info.compTypeCtxtArg = BAD_VAR_NUM;
}
lvaCount = info.compLocalsCount = info.compArgsCount + info.compMethodInfo->locals.numArgs;
info.compILlocalsCount = info.compILargsCount + info.compMethodInfo->locals.numArgs;
/* Now allocate the variable descriptor table */
if (compIsForInlining())
{
lvaTable = impInlineInfo->InlinerCompiler->lvaTable;
lvaCount = impInlineInfo->InlinerCompiler->lvaCount;
lvaTableCnt = impInlineInfo->InlinerCompiler->lvaTableCnt;
// No more stuff needs to be done.
return;
}
lvaTableCnt = lvaCount * 2;
if (lvaTableCnt < 16)
{
lvaTableCnt = 16;
}
lvaTable = (LclVarDsc*)compGetMemArray(lvaTableCnt, sizeof(*lvaTable), CMK_LvaTable);
size_t tableSize = lvaTableCnt * sizeof(*lvaTable);
memset(lvaTable, 0, tableSize);
for (unsigned i = 0; i < lvaTableCnt; i++)
{
new (&lvaTable[i], jitstd::placement_t()) LclVarDsc(this); // call the constructor.
}
//-------------------------------------------------------------------------
// Count the arguments and initialize the respective lvaTable[] entries
//
// First the implicit arguments
//-------------------------------------------------------------------------
InitVarDscInfo varDscInfo;
varDscInfo.Init(lvaTable, hasRetBuffArg);
lvaInitArgs(&varDscInfo);
//-------------------------------------------------------------------------
// Finally the local variables
//-------------------------------------------------------------------------
unsigned varNum = varDscInfo.varNum;
LclVarDsc* varDsc = varDscInfo.varDsc;
CORINFO_ARG_LIST_HANDLE localsSig = info.compMethodInfo->locals.args;
for (unsigned i = 0; i < info.compMethodInfo->locals.numArgs;
i++, varNum++, varDsc++, localsSig = info.compCompHnd->getArgNext(localsSig))
{
CORINFO_CLASS_HANDLE typeHnd;
CorInfoTypeWithMod corInfoTypeWithMod =
info.compCompHnd->getArgType(&info.compMethodInfo->locals, localsSig, &typeHnd);
CorInfoType corInfoType = strip(corInfoTypeWithMod);
lvaInitVarDsc(varDsc, varNum, corInfoType, typeHnd, localsSig, &info.compMethodInfo->locals);
varDsc->lvPinned = ((corInfoTypeWithMod & CORINFO_TYPE_MOD_PINNED) != 0);
varDsc->lvOnFrame = true; // The final home for this local variable might be our local stack frame
if (corInfoType == CORINFO_TYPE_CLASS)
{
CORINFO_CLASS_HANDLE clsHnd = info.compCompHnd->getArgClass(&info.compMethodInfo->locals, localsSig);
lvaSetClass(varNum, clsHnd);
}
}
if ( // If there already exist unsafe buffers, don't mark more structs as unsafe
// as that will cause them to be placed along with the real unsafe buffers,
// unnecessarily exposing them to overruns. This can affect GS tests which
// intentionally do buffer-overruns.
!getNeedsGSSecurityCookie() &&
// GS checks require the stack to be re-ordered, which can't be done with EnC
!opts.compDbgEnC && compStressCompile(STRESS_UNSAFE_BUFFER_CHECKS, 25))
{
setNeedsGSSecurityCookie();
compGSReorderStackLayout = true;
for (unsigned i = 0; i < lvaCount; i++)
{
if ((lvaTable[i].lvType == TYP_STRUCT) && compStressCompile(STRESS_GENERIC_VARN, 60))
{
lvaTable[i].lvIsUnsafeBuffer = true;
}
}
}
if (getNeedsGSSecurityCookie())
{
// Ensure that there will be at least one stack variable since
// we require that the GSCookie does not have a 0 stack offset.
unsigned dummy = lvaGrabTempWithImplicitUse(false DEBUGARG("GSCookie dummy"));
lvaTable[dummy].lvType = TYP_INT;
}
// Allocate the lvaOutgoingArgSpaceVar now because we can run into problems in the
// emitter when the varNum is greater that 32767 (see emitLclVarAddr::initLclVarAddr)
lvaAllocOutgoingArgSpaceVar();
#ifdef DEBUG
if (verbose)
{
lvaTableDump(INITIAL_FRAME_LAYOUT);
}
#endif
}
/*****************************************************************************/
void Compiler::lvaInitArgs(InitVarDscInfo* varDscInfo)
{
compArgSize = 0;
#if defined(_TARGET_ARM_) && defined(PROFILING_SUPPORTED)
// Prespill all argument regs on to stack in case of Arm when under profiler.
if (compIsProfilerHookNeeded())
{
codeGen->regSet.rsMaskPreSpillRegArg |= RBM_ARG_REGS;
}
#endif
//----------------------------------------------------------------------
/* Is there a "this" pointer ? */
lvaInitThisPtr(varDscInfo);
/* If we have a hidden return-buffer parameter, that comes here */
lvaInitRetBuffArg(varDscInfo);
//======================================================================
#if USER_ARGS_COME_LAST
//@GENERICS: final instantiation-info argument for shared generic methods
// and shared generic struct instance methods
lvaInitGenericsCtxt(varDscInfo);
/* If the method is varargs, process the varargs cookie */
lvaInitVarArgsHandle(varDscInfo);
#endif
//-------------------------------------------------------------------------
// Now walk the function signature for the explicit user arguments
//-------------------------------------------------------------------------
lvaInitUserArgs(varDscInfo);
#if !USER_ARGS_COME_LAST
//@GENERICS: final instantiation-info argument for shared generic methods
// and shared generic struct instance methods
lvaInitGenericsCtxt(varDscInfo);
/* If the method is varargs, process the varargs cookie */
lvaInitVarArgsHandle(varDscInfo);
#endif
//----------------------------------------------------------------------
// We have set info.compArgsCount in compCompile()
noway_assert(varDscInfo->varNum == info.compArgsCount);
assert(varDscInfo->intRegArgNum <= MAX_REG_ARG);
codeGen->intRegState.rsCalleeRegArgCount = varDscInfo->intRegArgNum;
#if !FEATURE_STACK_FP_X87
codeGen->floatRegState.rsCalleeRegArgCount = varDscInfo->floatRegArgNum;
#endif // FEATURE_STACK_FP_X87
#if FEATURE_FASTTAILCALL
// Save the stack usage information
// We can get register usage information using codeGen->intRegState and
// codeGen->floatRegState
info.compArgStackSize = varDscInfo->stackArgSize;
info.compHasMultiSlotArgs = varDscInfo->hasMultiSlotStruct;
#endif // FEATURE_FASTTAILCALL
// The total argument size must be aligned.
noway_assert((compArgSize % TARGET_POINTER_SIZE) == 0);
#ifdef _TARGET_X86_
/* We can not pass more than 2^16 dwords as arguments as the "ret"
instruction can only pop 2^16 arguments. Could be handled correctly
but it will be very difficult for fully interruptible code */
if (compArgSize != (size_t)(unsigned short)compArgSize)
NO_WAY("Too many arguments for the \"ret\" instruction to pop");
#endif
}
/*****************************************************************************/
void Compiler::lvaInitThisPtr(InitVarDscInfo* varDscInfo)
{
LclVarDsc* varDsc = varDscInfo->varDsc;
if (!info.compIsStatic)
{
varDsc->lvIsParam = 1;
#if ASSERTION_PROP
varDsc->lvSingleDef = 1;
#endif
varDsc->lvIsPtr = 1;
lvaArg0Var = info.compThisArg = varDscInfo->varNum;
noway_assert(info.compThisArg == 0);
if (eeIsValueClass(info.compClassHnd))
{
varDsc->lvType = TYP_BYREF;
#ifdef FEATURE_SIMD
if (featureSIMD)
{
var_types simdBaseType = TYP_UNKNOWN;
var_types type = impNormStructType(info.compClassHnd, nullptr, nullptr, &simdBaseType);
if (simdBaseType != TYP_UNKNOWN)
{
assert(varTypeIsSIMD(type));
varDsc->lvSIMDType = true;
varDsc->lvBaseType = simdBaseType;
varDsc->lvExactSize = genTypeSize(type);
}
}
#endif // FEATURE_SIMD
}
else
{
varDsc->lvType = TYP_REF;
lvaSetClass(varDscInfo->varNum, info.compClassHnd);
}
if (tiVerificationNeeded)
{
varDsc->lvVerTypeInfo = verMakeTypeInfo(info.compClassHnd);
if (varDsc->lvVerTypeInfo.IsValueClass())
{
varDsc->lvVerTypeInfo.MakeByRef();
}
}
else
{
varDsc->lvVerTypeInfo = typeInfo();
}
// Mark the 'this' pointer for the method
varDsc->lvVerTypeInfo.SetIsThisPtr();
varDsc->lvIsRegArg = 1;
noway_assert(varDscInfo->intRegArgNum == 0);
varDsc->lvArgReg = genMapRegArgNumToRegNum(varDscInfo->allocRegArg(TYP_INT), varDsc->TypeGet());
#if FEATURE_MULTIREG_ARGS
varDsc->lvOtherArgReg = REG_NA;
#endif
varDsc->setPrefReg(varDsc->lvArgReg, this);
varDsc->lvOnFrame = true; // The final home for this incoming register might be our local stack frame
#ifdef DEBUG
if (verbose)
{
printf("'this' passed in register %s\n", getRegName(varDsc->lvArgReg));
}
#endif
compArgSize += TARGET_POINTER_SIZE;
varDscInfo->varNum++;
varDscInfo->varDsc++;
}
}
/*****************************************************************************/
void Compiler::lvaInitRetBuffArg(InitVarDscInfo* varDscInfo)
{
LclVarDsc* varDsc = varDscInfo->varDsc;
bool hasRetBuffArg = impMethodInfo_hasRetBuffArg(info.compMethodInfo);
// These two should always match
noway_assert(hasRetBuffArg == varDscInfo->hasRetBufArg);
if (hasRetBuffArg)
{
info.compRetBuffArg = varDscInfo->varNum;
varDsc->lvType = TYP_BYREF;
varDsc->lvIsParam = 1;
varDsc->lvIsRegArg = 1;
#if ASSERTION_PROP
varDsc->lvSingleDef = 1;
#endif
if (hasFixedRetBuffReg())
{
varDsc->lvArgReg = theFixedRetBuffReg();
}
else
{
unsigned retBuffArgNum = varDscInfo->allocRegArg(TYP_INT);
varDsc->lvArgReg = genMapIntRegArgNumToRegNum(retBuffArgNum);
}
#if FEATURE_MULTIREG_ARGS
varDsc->lvOtherArgReg = REG_NA;
#endif
varDsc->setPrefReg(varDsc->lvArgReg, this);
varDsc->lvOnFrame = true; // The final home for this incoming register might be our local stack frame
info.compRetBuffDefStack = 0;
if (info.compRetType == TYP_STRUCT)
{
CORINFO_SIG_INFO sigInfo;
info.compCompHnd->getMethodSig(info.compMethodHnd, &sigInfo);
assert(JITtype2varType(sigInfo.retType) == info.compRetType); // Else shouldn't have a ret buff.
info.compRetBuffDefStack =
(info.compCompHnd->isStructRequiringStackAllocRetBuf(sigInfo.retTypeClass) == TRUE);
if (info.compRetBuffDefStack)
{
// If we're assured that the ret buff argument points into a callers stack, we will type it as
// "TYP_I_IMPL"
// (native int/unmanaged pointer) so that it's not tracked as a GC ref.
varDsc->lvType = TYP_I_IMPL;
}
}
#ifdef FEATURE_SIMD
else if (featureSIMD && varTypeIsSIMD(info.compRetType))
{
varDsc->lvSIMDType = true;
varDsc->lvBaseType =
getBaseTypeAndSizeOfSIMDType(info.compMethodInfo->args.retTypeClass, &varDsc->lvExactSize);
assert(varDsc->lvBaseType != TYP_UNKNOWN);
}
#endif // FEATURE_SIMD
assert(isValidIntArgReg(varDsc->lvArgReg));
#ifdef DEBUG
if (verbose)
{
printf("'__retBuf' passed in register %s\n", getRegName(varDsc->lvArgReg));
}
#endif
/* Update the total argument size, count and varDsc */
compArgSize += TARGET_POINTER_SIZE;
varDscInfo->varNum++;
varDscInfo->varDsc++;
}
}
/*****************************************************************************/
void Compiler::lvaInitUserArgs(InitVarDscInfo* varDscInfo)
{
//-------------------------------------------------------------------------
// Walk the function signature for the explicit arguments
//-------------------------------------------------------------------------
#if defined(_TARGET_X86_)
// Only (some of) the implicit args are enregistered for varargs
varDscInfo->maxIntRegArgNum = info.compIsVarArgs ? varDscInfo->intRegArgNum : MAX_REG_ARG;
#elif defined(_TARGET_AMD64_) && !defined(UNIX_AMD64_ABI)
// On System V type environment the float registers are not indexed together with the int ones.
varDscInfo->floatRegArgNum = varDscInfo->intRegArgNum;
#endif // _TARGET_*
CORINFO_ARG_LIST_HANDLE argLst = info.compMethodInfo->args.args;
const unsigned argSigLen = info.compMethodInfo->args.numArgs;
regMaskTP doubleAlignMask = RBM_NONE;
for (unsigned i = 0; i < argSigLen;
i++, varDscInfo->varNum++, varDscInfo->varDsc++, argLst = info.compCompHnd->getArgNext(argLst))
{
LclVarDsc* varDsc = varDscInfo->varDsc;
CORINFO_CLASS_HANDLE typeHnd = nullptr;
CorInfoTypeWithMod corInfoType = info.compCompHnd->getArgType(&info.compMethodInfo->args, argLst, &typeHnd);
varDsc->lvIsParam = 1;
#if ASSERTION_PROP
varDsc->lvSingleDef = 1;
#endif
lvaInitVarDsc(varDsc, varDscInfo->varNum, strip(corInfoType), typeHnd, argLst, &info.compMethodInfo->args);
if (strip(corInfoType) == CORINFO_TYPE_CLASS)
{
CORINFO_CLASS_HANDLE clsHnd = info.compCompHnd->getArgClass(&info.compMethodInfo->args, argLst);
lvaSetClass(varDscInfo->varNum, clsHnd);
}
// For ARM, ARM64, and AMD64 varargs, all arguments go in integer registers
var_types argType = mangleVarArgsType(varDsc->TypeGet());
var_types origArgType = argType;
// ARM softfp calling convention should affect only the floating point arguments.
// Otherwise there appear too many surplus pre-spills and other memory operations
// with the associated locations .
bool isSoftFPPreSpill = opts.compUseSoftFP && varTypeIsFloating(varDsc->TypeGet());
unsigned argSize = eeGetArgSize(argLst, &info.compMethodInfo->args);
unsigned cSlots = argSize / TARGET_POINTER_SIZE; // the total number of slots of this argument
bool isHfaArg = false;
var_types hfaType = TYP_UNDEF;
// Methods that use VarArg or SoftFP cannot have HFA arguments
if (!info.compIsVarArgs && !opts.compUseSoftFP)
{
// If the argType is a struct, then check if it is an HFA
if (varTypeIsStruct(argType))
{
hfaType = GetHfaType(typeHnd); // set to float or double if it is an HFA, otherwise TYP_UNDEF
isHfaArg = varTypeIsFloating(hfaType);
}
}
if (isHfaArg)
{
// We have an HFA argument, so from here on out treat the type as a float or double.
// The orginal struct type is available by using origArgType
// We also update the cSlots to be the number of float/double fields in the HFA
argType = hfaType;
cSlots = varDsc->lvHfaSlots();
}
// The number of slots that must be enregistered if we are to consider this argument enregistered.
// This is normally the same as cSlots, since we normally either enregister the entire object,
// or none of it. For structs on ARM, however, we only need to enregister a single slot to consider
// it enregistered, as long as we can split the rest onto the stack.
unsigned cSlotsToEnregister = cSlots;
#ifdef _TARGET_ARM_
// On ARM we pass the first 4 words of integer arguments and non-HFA structs in registers.
// But we pre-spill user arguments in varargs methods and structs.
//
unsigned cAlign;
bool preSpill = info.compIsVarArgs || isSoftFPPreSpill;
switch (origArgType)
{
case TYP_STRUCT:
assert(varDsc->lvSize() == argSize);
cAlign = varDsc->lvStructDoubleAlign ? 2 : 1;
// HFA arguments go on the stack frame. They don't get spilled in the prolog like struct
// arguments passed in the integer registers but get homed immediately after the prolog.
if (!isHfaArg)
{
cSlotsToEnregister = 1; // HFAs must be totally enregistered or not, but other structs can be split.
preSpill = true;
}
break;
case TYP_DOUBLE:
case TYP_LONG:
cAlign = 2;
break;
default:
cAlign = 1;
break;
}
if (isRegParamType(argType))
{
compArgSize += varDscInfo->alignReg(argType, cAlign) * REGSIZE_BYTES;
}
if (argType == TYP_STRUCT)
{
// Are we going to split the struct between registers and stack? We can do that as long as
// no floating-point arguments have been put on the stack.
//
// From the ARM Procedure Call Standard:
// Rule C.5: "If the NCRN is less than r4 **and** the NSAA is equal to the SP,"
// then split the argument between registers and stack. Implication: if something
// has already been spilled to the stack, then anything that would normally be
// split between the core registers and the stack will be put on the stack.
// Anything that follows will also be on the stack. However, if something from
// floating point regs has been spilled to the stack, we can still use r0-r3 until they are full.
if (varDscInfo->canEnreg(TYP_INT, 1) && // The beginning of the struct can go in a register
!varDscInfo->canEnreg(TYP_INT, cSlots) && // The end of the struct can't fit in a register
varDscInfo->existAnyFloatStackArgs()) // There's at least one stack-based FP arg already
{
varDscInfo->setAllRegArgUsed(TYP_INT); // Prevent all future use of integer registers
preSpill = false; // This struct won't be prespilled, since it will go on the stack
}
}
if (preSpill)
{
for (unsigned ix = 0; ix < cSlots; ix++)
{
if (!varDscInfo->canEnreg(TYP_INT, ix + 1))
{
break;
}
regMaskTP regMask = genMapArgNumToRegMask(varDscInfo->regArgNum(TYP_INT) + ix, TYP_INT);
if (cAlign == 2)
{
doubleAlignMask |= regMask;
}
codeGen->regSet.rsMaskPreSpillRegArg |= regMask;
}
}
#else // !_TARGET_ARM_
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
SYSTEMV_AMD64_CORINFO_STRUCT_REG_PASSING_DESCRIPTOR structDesc;
if (varTypeIsStruct(argType))
{
assert(typeHnd != nullptr);
eeGetSystemVAmd64PassStructInRegisterDescriptor(typeHnd, &structDesc);
if (structDesc.passedInRegisters)
{
unsigned intRegCount = 0;
unsigned floatRegCount = 0;
for (unsigned int i = 0; i < structDesc.eightByteCount; i++)
{
if (structDesc.IsIntegralSlot(i))
{
intRegCount++;
}
else if (structDesc.IsSseSlot(i))
{
floatRegCount++;
}
else
{
assert(false && "Invalid eightbyte classification type.");
break;
}
}
if (intRegCount != 0 && !varDscInfo->canEnreg(TYP_INT, intRegCount))
{
structDesc.passedInRegisters = false; // No register to enregister the eightbytes.
}
if (floatRegCount != 0 && !varDscInfo->canEnreg(TYP_FLOAT, floatRegCount))
{
structDesc.passedInRegisters = false; // No register to enregister the eightbytes.
}
}
}
#endif // FEATURE_UNIX_AMD64_STRUCT_PASSING
#endif // !_TARGET_ARM_
// The final home for this incoming register might be our local stack frame.
// For System V platforms the final home will always be on the local stack frame.
varDsc->lvOnFrame = true;
bool canPassArgInRegisters = false;
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
if (varTypeIsStruct(argType))
{
canPassArgInRegisters = structDesc.passedInRegisters;
}
else
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
{
canPassArgInRegisters = varDscInfo->canEnreg(argType, cSlotsToEnregister);
}
if (canPassArgInRegisters)
{
/* Another register argument */
// Allocate the registers we need. allocRegArg() returns the first argument register number of the set.
// For non-HFA structs, we still "try" to enregister the whole thing; it will just max out if splitting
// to the stack happens.
unsigned firstAllocatedRegArgNum = 0;
#if FEATURE_MULTIREG_ARGS
varDsc->lvOtherArgReg = REG_NA;
#endif // FEATURE_MULTIREG_ARGS
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
unsigned secondAllocatedRegArgNum = 0;
var_types firstEightByteType = TYP_UNDEF;
var_types secondEightByteType = TYP_UNDEF;
if (varTypeIsStruct(argType))
{
if (structDesc.eightByteCount >= 1)
{
firstEightByteType = GetEightByteType(structDesc, 0);
firstAllocatedRegArgNum = varDscInfo->allocRegArg(firstEightByteType, 1);
}
}
else
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
{
firstAllocatedRegArgNum = varDscInfo->allocRegArg(argType, cSlots);
}
if (isHfaArg)
{
// We need to save the fact that this HFA is enregistered
varDsc->lvSetIsHfa();
varDsc->lvSetIsHfaRegArg();
varDsc->SetHfaType(hfaType);
varDsc->lvIsMultiRegArg = (varDsc->lvHfaSlots() > 1);
}
varDsc->lvIsRegArg = 1;
#if FEATURE_MULTIREG_ARGS
if (varTypeIsStruct(argType))
{
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
varDsc->lvArgReg = genMapRegArgNumToRegNum(firstAllocatedRegArgNum, firstEightByteType);
// If there is a second eightbyte, get a register for it too and map the arg to the reg number.
if (structDesc.eightByteCount >= 2)
{
secondEightByteType = GetEightByteType(structDesc, 1);
secondAllocatedRegArgNum = varDscInfo->allocRegArg(secondEightByteType, 1);
varDscInfo->hasMultiSlotStruct = true;
}
if (secondEightByteType != TYP_UNDEF)
{
varDsc->lvOtherArgReg = genMapRegArgNumToRegNum(secondAllocatedRegArgNum, secondEightByteType);
varDsc->addPrefReg(genRegMask(varDsc->lvOtherArgReg), this);
}
#else // ARM32 or ARM64
varDsc->lvArgReg = genMapRegArgNumToRegNum(firstAllocatedRegArgNum, TYP_I_IMPL);
#ifdef _TARGET_ARM64_
if (cSlots == 2)
{
varDsc->lvOtherArgReg = genMapRegArgNumToRegNum(firstAllocatedRegArgNum + 1, TYP_I_IMPL);
varDsc->addPrefReg(genRegMask(varDsc->lvOtherArgReg), this);
varDscInfo->hasMultiSlotStruct = true;
}
#endif // _TARGET_ARM64_
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
}
else
#endif // FEATURE_MULTIREG_ARGS
{
varDsc->lvArgReg = genMapRegArgNumToRegNum(firstAllocatedRegArgNum, argType);
}
varDsc->setPrefReg(varDsc->lvArgReg, this);
#ifdef _TARGET_ARM_
if (varDsc->TypeGet() == TYP_LONG)
{
varDsc->lvOtherReg = genMapRegArgNumToRegNum(firstAllocatedRegArgNum + 1, TYP_INT);
varDsc->addPrefReg(genRegMask(varDsc->lvOtherReg), this);
}
#endif // _TARGET_ARM_
#ifdef DEBUG
if (verbose)
{
printf("Arg #%u passed in register(s) ", varDscInfo->varNum);
bool isFloat = false;
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
// In case of one eightbyte struct the type is already normalized earlier.
// The varTypeIsFloating(argType) is good for this case.
if (varTypeIsStruct(argType) && (structDesc.eightByteCount >= 1))
{
isFloat = varTypeIsFloating(firstEightByteType);
}
else
#else // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
{
isFloat = varTypeIsFloating(argType);
}
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
#if defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
if (varTypeIsStruct(argType))
{
// Print both registers, just to be clear
if (firstEightByteType == TYP_UNDEF)
{
printf("firstEightByte: <not used>");
}
else
{
printf("firstEightByte: %s",
getRegName(genMapRegArgNumToRegNum(firstAllocatedRegArgNum, firstEightByteType),
isFloat));
}
if (secondEightByteType == TYP_UNDEF)
{
printf(", secondEightByte: <not used>");
}
else
{
printf(", secondEightByte: %s",
getRegName(genMapRegArgNumToRegNum(secondAllocatedRegArgNum, secondEightByteType),
varTypeIsFloating(secondEightByteType)));
}
}
else
#endif // defined(FEATURE_UNIX_AMD64_STRUCT_PASSING)
{
unsigned regArgNum = genMapRegNumToRegArgNum(varDsc->lvArgReg, argType);
for (unsigned ix = 0; ix < cSlots; ix++, regArgNum++)
{
if (ix > 0)
{
printf(",");
}
if (!isFloat && (regArgNum >= varDscInfo->maxIntRegArgNum)) // a struct has been split between
// registers and stack
{
printf(" stack slots:%d", cSlots - ix);
break;
}
#ifdef _TARGET_ARM_
if (isFloat)
{
// Print register size prefix
if (argType == TYP_DOUBLE)
{
// Print both registers, just to be clear
printf("%s/%s", getRegName(genMapRegArgNumToRegNum(regArgNum, argType), isFloat),
getRegName(genMapRegArgNumToRegNum(regArgNum + 1, argType), isFloat));
// doubles take 2 slots
assert(ix + 1 < cSlots);
++ix;
++regArgNum;
}
else
{
printf("%s", getRegName(genMapRegArgNumToRegNum(regArgNum, argType), isFloat));
}
}
else
#endif // _TARGET_ARM_
{
printf("%s", getRegName(genMapRegArgNumToRegNum(regArgNum, argType), isFloat));
}
}
}
printf("\n");
}
#endif // DEBUG
} // end if (canPassArgInRegisters)
else
{
#if defined(_TARGET_ARM_)
varDscInfo->setAllRegArgUsed(argType);
if (varTypeIsFloating(argType))
{
varDscInfo->setAnyFloatStackArgs();
}
#elif defined(_TARGET_ARM64_)
// If we needed to use the stack in order to pass this argument then
// record the fact that we have used up any remaining registers of this 'type'
// This prevents any 'backfilling' from occuring on ARM64
//
varDscInfo->setAllRegArgUsed(argType);
#endif // _TARGET_XXX_
#if FEATURE_FASTTAILCALL
varDscInfo->stackArgSize += (unsigned)roundUp(argSize, TARGET_POINTER_SIZE);
#endif // FEATURE_FASTTAILCALL
}
#ifdef FEATURE_UNIX_AMD64_STRUCT_PASSING
// The arg size is returning the number of bytes of the argument. For a struct it could return a size not a
// multiple of TARGET_POINTER_SIZE. The stack allocated space should always be multiple of TARGET_POINTER_SIZE,
// so round it up.
compArgSize += (unsigned)roundUp(argSize, TARGET_POINTER_SIZE);
#else // !FEATURE_UNIX_AMD64_STRUCT_PASSING
compArgSize += argSize;
#endif // !FEATURE_UNIX_AMD64_STRUCT_PASSING
if (info.compIsVarArgs || isHfaArg || isSoftFPPreSpill)
{
#if defined(_TARGET_X86_)
varDsc->lvStkOffs = compArgSize;
#else // !_TARGET_X86_
// TODO-CQ: We shouldn't have to go as far as to declare these
// address-exposed -- DoNotEnregister should suffice.
lvaSetVarAddrExposed(varDscInfo->varNum);
#endif // !_TARGET_X86_
}
} // for each user arg
#ifdef _TARGET_ARM_
if (doubleAlignMask != RBM_NONE)
{
assert(RBM_ARG_REGS == 0xF);
assert((doubleAlignMask & RBM_ARG_REGS) == doubleAlignMask);
if (doubleAlignMask != RBM_NONE && doubleAlignMask != RBM_ARG_REGS)
{
// doubleAlignMask can only be 0011 and/or 1100 as 'double aligned types' can
// begin at r0 or r2.
assert(doubleAlignMask == 0x3 || doubleAlignMask == 0xC /* || 0xF is if'ed out */);
// Now if doubleAlignMask is 0011 i.e., {r0,r1} and we prespill r2 or r3
// but not both, then the stack would be misaligned for r0. So spill both
// r2 and r3.
//
// ; +0 --- caller SP double aligned ----
// ; -4 r2 r3
// ; -8 r1 r1
// ; -c r0 r0 <-- misaligned.