com.oracle.svm.core.graal.lir

Class VerifyCFunctionReferenceMapsLIRPhase

java.lang.Object

org.graalvm.compiler.lir.phases.LIRPhase<org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase.PostAllocationOptimizationContext>

org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase

com.oracle.svm.core.graal.lir.VerifyCFunctionReferenceMapsLIRPhase

public class VerifyCFunctionReferenceMapsLIRPhase
extends org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase

Verifies that reference maps for C function calls are correct. See CFunctionSnippets for details on the thread state transitions. In the machine code, there are three instructions that have a reference map: the address loaded as the "last Java instruction pointer", the C function call, and the slow-path call to block at a safepoint. The first two are the same LIR instruction, therefore, in this phase we only see two LIR instructions: the C function call and the slow-path call. This phase verifies that these two calls have the same reference map. As long as the thread is in Native state, the safepoint manager can transition it into the Safepoint state at any time and the safepoint code can start walking the stack, using the JavaFrameAnchor. This means that the GC can scan the stack for roots any time while we are in the C function, while we are in the slow-path call, or while transitioning between those two calls. Having different reference maps would lead to wrong roots and therefore a crash of the GC.

Nested Class Summary

Nested classes/interfaces inherited from class org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase

org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase.PostAllocationOptimizationContext

Nested classes/interfaces inherited from class org.graalvm.compiler.lir.phases.LIRPhase

org.graalvm.compiler.lir.phases.LIRPhase.LIRPhaseStatistics, org.graalvm.compiler.lir.phases.LIRPhase.Options

Field Summary

Fields inherited from class org.graalvm.compiler.lir.phases.LIRPhase

statisticsClassValue

Constructor Summary

Constructors

Constructor and Description
VerifyCFunctionReferenceMapsLIRPhase()

Method Summary

Modifier and Type	Method and Description
protected CharSequence	createName()
protected void	run(jdk.vm.ci.code.TargetDescription target, org.graalvm.compiler.lir.gen.LIRGenerationResult lirGenRes, org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase.PostAllocationOptimizationContext context)

Methods inherited from class org.graalvm.compiler.lir.phases.LIRPhase

apply, apply, createName, getLIRPhaseStatistics, getName

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

VerifyCFunctionReferenceMapsLIRPhase

public VerifyCFunctionReferenceMapsLIRPhase()

Method Detail

createName

protected CharSequence createName()

Overrides:

createName in class org.graalvm.compiler.lir.phases.LIRPhase<org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase.PostAllocationOptimizationContext>

run

protected void run(jdk.vm.ci.code.TargetDescription target,
                   org.graalvm.compiler.lir.gen.LIRGenerationResult lirGenRes,
                   org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase.PostAllocationOptimizationContext context)

Specified by:

run in class org.graalvm.compiler.lir.phases.LIRPhase<org.graalvm.compiler.lir.phases.PostAllocationOptimizationPhase.PostAllocationOptimizationContext>