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8043137: Collapse long sequences of NOP in Nashorn bytecode output

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Reviewed-by: jlaskey, lagergren
This commit is contained in:
Attila Szegedi 2014-05-14 16:29:14 +02:00
parent 9f521f94cc
commit a305329ba1
1 changed files with 26 additions and 1 deletions
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27
nashorn/src/jdk/nashorn/internal/ir/debug/NashornTextifier.java
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@ -61,6 +61,12 @@ public final class NashornTextifier extends Printer {
private Graph graph;
private String currentBlock;
// Following variables are used to govern the state of collapsing long sequences of NOP.
/** True if the last instruction was a NOP. */
private boolean lastWasNop = false;
/** True if ellipse ("...") was emitted in place of a second NOP. */
private boolean lastWasEllipse = false;
private static final int INTERNAL_NAME = 0;
private static final int FIELD_DESCRIPTOR = 1;
private static final int FIELD_SIGNATURE = 2;
@ -394,7 +400,7 @@ public final class NashornTextifier extends Printer {
}
private StringBuilder appendOpcode(final StringBuilder sb, final int opcode) {
final Label next = labelIter == null ? null : labelIter.next();
final Label next = getNextLabel();
if (next instanceof NashornLabel) {
final int bci = next.getOffset();
if (bci != -1) {
@ -412,8 +418,27 @@ public final class NashornTextifier extends Printer {
return sb.append(tab2).append(OPCODES[opcode].toLowerCase());
}
private Label getNextLabel() {
return labelIter == null ? null : labelIter.next();
}
@Override
public void visitInsn(final int opcode) {
if(opcode == Opcodes.NOP) {
if(lastWasEllipse) {
getNextLabel();
return;
} else if(lastWasNop) {
getNextLabel();
addText(" ...\n");
lastWasEllipse = true;
return;
} else {
lastWasNop = true;
}
} else {
lastWasNop = lastWasEllipse = false;
}
final StringBuilder sb = new StringBuilder();
appendOpcode(sb, opcode).append('\n');
addText(sb);