265 /** This is only for use by the debugging system, and is only
266 intended for use in the topmost frame, where we are not
267 guaranteed to be at a PC for which we have a PCDesc. It finds
268 the PCDesc with realPC closest to the current PC. */
269 public PCDesc getPCDescNearDbg(Address pc) {
270 PCDesc bestGuessPCDesc = null;
271 long bestDistance = 0;
272 for (Address p = scopesPCsBegin(); p.lessThan(scopesPCsEnd()); p = p.addOffsetTo(pcDescSize)) {
273 PCDesc pcDesc = new PCDesc(p);
274 // In case pc is null
275 long distance = -pcDesc.getRealPC(this).minus(pc);
276 if ((bestGuessPCDesc == null) ||
277 ((distance >= 0) && (distance < bestDistance))) {
278 bestGuessPCDesc = pcDesc;
279 bestDistance = distance;
280 }
281 }
282 return bestGuessPCDesc;
283 }
284
285 /** This is only for use by the debugging system, and is only
286 intended for use in the topmost frame, where we are not
287 guaranteed to be at a PC for which we have a PCDesc. It finds
288 the ScopeDesc closest to the current PC. NOTE that this may
289 return NULL for compiled methods which don't have any
290 ScopeDescs! */
291 public ScopeDesc getScopeDescNearDbg(Address pc) {
292 PCDesc pd = getPCDescNearDbg(pc);
293 if (pd == null) return null;
294 return new ScopeDesc(this, pd.getScopeDecodeOffset(), pd.getReexecute());
295 }
296
297 public Map/*<Address, PcDesc>*/ getSafepoints() {
298 Map safepoints = new HashMap(); // Map<Address, PcDesc>
299 sun.jvm.hotspot.debugger.Address p = null;
300 for (p = scopesPCsBegin(); p.lessThan(scopesPCsEnd());
301 p = p.addOffsetTo(pcDescSize)) {
302 PCDesc pcDesc = new PCDesc(p);
303 sun.jvm.hotspot.debugger.Address pc = pcDesc.getRealPC(this);
304 safepoints.put(pc, pcDesc);
305 }
306 return safepoints;
307 }
308
309 // FIXME: add getPCOffsetForBCI()
310 // FIXME: add embeddedOopAt()
311 // FIXME: add isDependentOn()
312 // FIXME: add isPatchableAt()
313
314 /** Support for code generation. Only here for proof-of-concept. */
315 public static int getEntryPointOffset() { return (int) entryPointField.getOffset(); }
316 public static int getVerifiedEntryPointOffset() { return (int) verifiedEntryPointField.getOffset(); }
317 public static int getOSREntryPointOffset() { return (int) osrEntryPointField.getOffset(); }
318 public static int getEntryBCIOffset() { return (int) entryBCIField.getOffset(); }
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265 /** This is only for use by the debugging system, and is only
266 intended for use in the topmost frame, where we are not
267 guaranteed to be at a PC for which we have a PCDesc. It finds
268 the PCDesc with realPC closest to the current PC. */
269 public PCDesc getPCDescNearDbg(Address pc) {
270 PCDesc bestGuessPCDesc = null;
271 long bestDistance = 0;
272 for (Address p = scopesPCsBegin(); p.lessThan(scopesPCsEnd()); p = p.addOffsetTo(pcDescSize)) {
273 PCDesc pcDesc = new PCDesc(p);
274 // In case pc is null
275 long distance = -pcDesc.getRealPC(this).minus(pc);
276 if ((bestGuessPCDesc == null) ||
277 ((distance >= 0) && (distance < bestDistance))) {
278 bestGuessPCDesc = pcDesc;
279 bestDistance = distance;
280 }
281 }
282 return bestGuessPCDesc;
283 }
284
285 PCDesc find_pc_desc(long pc, boolean approximate) {
286 return find_pc_desc_internal(pc, approximate);
287 }
288
289 static long addressToLong(sun.jvm.hotspot.debugger.Address addr) {
290 return VM.getVM().getDebugger().getAddressValue(addr);
291 }
292
293 // Finds a PcDesc with real-pc equal to "pc"
294 PCDesc find_pc_desc_internal(long pc, boolean approximate) {
295 long base_address = addressToLong(instructionsBegin());
296 int pc_offset = (int) (pc - base_address);
297
298 // Fallback algorithm: quasi-linear search for the PcDesc
299 // Find the last pc_offset less than the given offset.
300 // The successor must be the required match, if there is a match at all.
301 // (Use a fixed radix to avoid expensive affine pointer arithmetic.)
302 Address lower = scopesPCsBegin();
303 Address upper = scopesPCsEnd();
304 upper = upper.addOffsetTo(-pcDescSize); // exclude final sentinel
305 if (lower.greaterThan(upper)) return null; // native method; no PcDescs at all
306
307 // Take giant steps at first (4096, then 256, then 16, then 1)
308 int LOG2_RADIX = 4;
309 int RADIX = (1 << LOG2_RADIX);
310 Address mid;
311 for (int step = (1 << (LOG2_RADIX*3)); step > 1; step >>= LOG2_RADIX) {
312 while ((mid = lower.addOffsetTo(step * pcDescSize)).lessThan(upper)) {
313 PCDesc m = new PCDesc(mid);
314 if (m.getPCOffset() < pc_offset) {
315 lower = mid;
316 } else {
317 upper = mid;
318 break;
319 }
320 }
321 }
322
323 // Sneak up on the value with a linear search of length ~16.
324 while (true) {
325 mid = lower.addOffsetTo(pcDescSize);
326 PCDesc m = new PCDesc(mid);
327 if (m.getPCOffset() < pc_offset) {
328 lower = mid;
329 } else {
330 upper = mid;
331 break;
332 }
333 }
334
335 PCDesc u = new PCDesc(upper);
336 if (match_desc(u, pc_offset, approximate)) {
337 return u;
338 } else {
339 return null;
340 }
341 }
342
343
344 // ScopeDesc retrieval operation
345 PCDesc pc_desc_at(long pc) { return find_pc_desc(pc, false); }
346 // pc_desc_near returns the first PCDesc at or after the givne pc.
347 PCDesc pc_desc_near(long pc) { return find_pc_desc(pc, true); }
348
349 // Return a the last scope in (begin..end]
350 public ScopeDesc scope_desc_in(long begin, long end) {
351 PCDesc p = pc_desc_near(begin+1);
352 if (p != null && addressToLong(p.getRealPC(this)) <= end) {
353 return new ScopeDesc(this, p.getScopeDecodeOffset(), p.getReexecute());
354 }
355 return null;
356 }
357
358 static boolean match_desc(PCDesc pc, int pc_offset, boolean approximate) {
359 if (!approximate)
360 return pc.getPCOffset() == pc_offset;
361 else {
362 PCDesc prev = new PCDesc(pc.getAddress().addOffsetTo(-pcDescSize));
363 return prev.getPCOffset() < pc_offset && pc_offset <= pc.getPCOffset();
364 }
365 }
366
367 /** This is only for use by the debugging system, and is only
368 intended for use in the topmost frame, where we are not
369 guaranteed to be at a PC for which we have a PCDesc. It finds
370 the ScopeDesc closest to the current PC. NOTE that this may
371 return NULL for compiled methods which don't have any
372 ScopeDescs! */
373 public ScopeDesc getScopeDescNearDbg(Address pc) {
374 PCDesc pd = getPCDescNearDbg(pc);
375 if (pd == null) return null;
376 return new ScopeDesc(this, pd.getScopeDecodeOffset(), pd.getReexecute());
377 }
378
379 public Map/*<Address, PCDesc>*/ getSafepoints() {
380 Map safepoints = new HashMap(); // Map<Address, PCDesc>
381 sun.jvm.hotspot.debugger.Address p = null;
382 for (p = scopesPCsBegin(); p.lessThan(scopesPCsEnd());
383 p = p.addOffsetTo(pcDescSize)) {
384 PCDesc pcDesc = new PCDesc(p);
385 sun.jvm.hotspot.debugger.Address pc = pcDesc.getRealPC(this);
386 safepoints.put(pc, pcDesc);
387 }
388 return safepoints;
389 }
390
391 // FIXME: add getPCOffsetForBCI()
392 // FIXME: add embeddedOopAt()
393 // FIXME: add isDependentOn()
394 // FIXME: add isPatchableAt()
395
396 /** Support for code generation. Only here for proof-of-concept. */
397 public static int getEntryPointOffset() { return (int) entryPointField.getOffset(); }
398 public static int getVerifiedEntryPointOffset() { return (int) verifiedEntryPointField.getOffset(); }
399 public static int getOSREntryPointOffset() { return (int) osrEntryPointField.getOffset(); }
400 public static int getEntryBCIOffset() { return (int) entryBCIField.getOffset(); }
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