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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.
#include "jitpch.h"
#ifdef _MSC_VER
#pragma hdrstop
#endif
#include "register_arg_convention.h"
unsigned InitVarDscInfo::allocRegArg(var_types type, unsigned numRegs /* = 1 */)
{
assert(numRegs > 0);
unsigned resultArgNum = regArgNum(type);
bool isBackFilled = false;
#ifdef _TARGET_ARM_
// Check for back-filling
if (varTypeIsFloating(type) && // We only back-fill the float registers
!anyFloatStackArgs && // Is it legal to back-fill? (We haven't put any FP args on the stack yet)
(numRegs == 1) && // Is there a possibility we could back-fill?
(fltArgSkippedRegMask != RBM_NONE)) // Is there an available back-fill slot?
{
// We will never back-fill something greater than a single register
// (TYP_FLOAT, or TYP_STRUCT HFA with a single float). This is because
// we don't have any types that require > 2 register alignment, so we
// can't create a > 1 register alignment hole to back-fill.
// Back-fill the register
regMaskTP backFillBitMask = genFindLowestBit(fltArgSkippedRegMask);
fltArgSkippedRegMask &= ~backFillBitMask; // Remove the back-filled register(s) from the skipped mask
resultArgNum = genMapFloatRegNumToRegArgNum(genRegNumFromMask(backFillBitMask));
assert(resultArgNum < MAX_FLOAT_REG_ARG);
isBackFilled = true;
}
#endif // _TARGET_ARM_
if (!isBackFilled)
{
#if defined(_TARGET_AMD64_) && !defined(UNIX_AMD64_ABI)
// For System V the reg type counters should be independent.
nextReg(TYP_INT, numRegs);
nextReg(TYP_FLOAT, numRegs);
#else
// We didn't back-fill a register (on ARM), so skip the number of registers that we allocated.
nextReg(type, numRegs);
#endif
}
return resultArgNum;
}
bool InitVarDscInfo::enoughAvailRegs(var_types type, unsigned numRegs /* = 1 */)
{
assert(numRegs > 0);
unsigned backFillCount = 0;
#ifdef _TARGET_ARM_
// Check for back-filling
if (varTypeIsFloating(type) && // We only back-fill the float registers
!anyFloatStackArgs && // Is it legal to back-fill? (We haven't put any FP args on the stack yet)
(numRegs == 1) && // Is there a possibility we could back-fill?
(fltArgSkippedRegMask != RBM_NONE)) // Is there an available back-fill slot?
{
backFillCount = 1;
}
#endif // _TARGET_ARM_
return regArgNum(type) + numRegs - backFillCount <= maxRegArgNum(type);
}
#ifdef _TARGET_ARM_
unsigned InitVarDscInfo::alignReg(var_types type, unsigned requiredRegAlignment)
{
assert(requiredRegAlignment > 0);
if (requiredRegAlignment == 1)
{
return 0; // Everything is always "1" aligned
}
assert(requiredRegAlignment == 2); // we don't expect anything else right now
int alignMask = regArgNum(type) & (requiredRegAlignment - 1);
if (alignMask == 0)
{
return 0; // We're already aligned
}
unsigned cAlignSkipped = requiredRegAlignment - alignMask;
assert(cAlignSkipped == 1); // Alignment is currently only 1 or 2, so misalignment can only be 1.
if (varTypeIsFloating(type))
{
fltArgSkippedRegMask |= genMapFloatRegArgNumToRegMask(floatRegArgNum);
}
assert(regArgNum(type) + cAlignSkipped <= maxRegArgNum(type)); // if equal, then we aligned the last slot, and the
// arg can't be enregistered
regArgNum(type) += cAlignSkipped;
return cAlignSkipped;
}
#endif // _TARGET_ARM_
bool InitVarDscInfo::canEnreg(var_types type, unsigned numRegs /* = 1 */)
{
if (!isRegParamType(type))
{
return false;
}
if (!enoughAvailRegs(type, numRegs))
{
return false;
}
return true;
}
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