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package org.graalvm.compiler.lir.sparc;

import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.REG;
import static jdk.vm.ci.code.ValueUtil.asRegister;

import org.graalvm.compiler.asm.sparc.SPARCAssembler;
import org.graalvm.compiler.asm.sparc.SPARCMacroAssembler;
import org.graalvm.compiler.lir.LIR;
import org.graalvm.compiler.lir.LIRInstructionClass;
import org.graalvm.compiler.lir.StandardOp.NoOp;
import org.graalvm.compiler.lir.Variable;
import org.graalvm.compiler.lir.asm.CompilationResultBuilder;

import jdk.vm.ci.code.Register;
import jdk.vm.ci.meta.AllocatableValue;

Loads the constant section base into a register.

Layout:

+----constant section----+--pad--+---code section--+
|<-------------------_------------------->|
                     ^- Constant section base pointer
The constant section base pointer is placed as such that the lowest offset -4096 points to the start of the constant section.

If the constant section grows beyond 8k size, the immediate addressing cannot be used anymore; in this case absolute addressing (without using the base pointer is used). See also: CodeInstaller::pd_patch_DataSectionReference

See Also:
  • loadFromConstantTable.loadFromConstantTable(CompilationResultBuilder, SPARCMacroAssembler, Register, Constant, Register, SPARCDelayedControlTransfer)
/** * Loads the constant section base into a register. * * <p> * Layout: * * <pre> * +----constant section----+--pad--+---code section--+ * |<-------------------_------------------->| * ^- Constant section base pointer * </pre> * * The constant section base pointer is placed as such that the lowest offset -4096 points to the * start of the constant section. * <p> * If the constant section grows beyond 8k size, the immediate addressing cannot be used anymore; in * this case absolute addressing (without using the base pointer is used). See also: * CodeInstaller::pd_patch_DataSectionReference * * @see SPARCMove#loadFromConstantTable(CompilationResultBuilder, SPARCMacroAssembler, Register, * jdk.vm.ci.meta.Constant, Register, SPARCDelayedControlTransfer) */
public class SPARCLoadConstantTableBaseOp extends SPARCLIRInstruction { public static final LIRInstructionClass<SPARCLoadConstantTableBaseOp> TYPE = LIRInstructionClass.create(SPARCLoadConstantTableBaseOp.class); public static final SizeEstimate SIZE = SizeEstimate.create(9); private final NoOp placeHolder; @Def({REG}) private AllocatableValue base; public SPARCLoadConstantTableBaseOp(Variable base, NoOp placeHolder) { super(TYPE, SIZE); this.base = base; this.placeHolder = placeHolder; } @Override public void emitCode(CompilationResultBuilder crb, SPARCMacroAssembler masm) { Register baseRegister = asRegister(base); int beforePosition = masm.position(); masm.rdpc(baseRegister); // Must match with CodeInstaller::pd_patch_DataSectionReference masm.add(baseRegister, (int) SPARCAssembler.minSimm(13), baseRegister); masm.sub(baseRegister, beforePosition, baseRegister); } public AllocatableValue getResult() { return base; } public void setAlive(LIR lir, boolean alive) { if (alive) { placeHolder.replace(lir, this); } else { placeHolder.remove(lir); } } }