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