xref: /llvm-project/lldb/unittests/Process/Utility/MemoryTagManagerAArch64MTETest.cpp (revision b1751faada35e3456b2a3f6b6c9559b5d74d559b)
1 //===-- MemoryTagManagerAArch64MTETest.cpp --------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "Plugins/Process/Utility/MemoryTagManagerAArch64MTE.h"
10 #include "llvm/Testing/Support/Error.h"
11 #include "gtest/gtest.h"
12 
13 using namespace lldb_private;
14 
15 TEST(MemoryTagManagerAArch64MTETest, UnpackTagsData) {
16   MemoryTagManagerAArch64MTE manager;
17 
18   // Error for insufficient tag data
19   std::vector<uint8_t> input;
20   ASSERT_THAT_EXPECTED(
21       manager.UnpackTagsData(input, 2),
22       llvm::FailedWithMessage(
23           "Packed tag data size does not match expected number of tags. "
24           "Expected 2 tag(s) for 2 granule(s), got 0 tag(s)."));
25 
26   // This is out of the valid tag range
27   input.push_back(0x1f);
28   ASSERT_THAT_EXPECTED(
29       manager.UnpackTagsData(input, 1),
30       llvm::FailedWithMessage(
31           "Found tag 0x1f which is > max MTE tag value of 0xf."));
32 
33   // MTE tags are 1 per byte
34   input.pop_back();
35   input.push_back(0xe);
36   input.push_back(0xf);
37 
38   std::vector<lldb::addr_t> expected{0xe, 0xf};
39 
40   llvm::Expected<std::vector<lldb::addr_t>> got =
41       manager.UnpackTagsData(input, 2);
42   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
43   ASSERT_THAT(expected, testing::ContainerEq(*got));
44 
45   // Error for too much tag data
46   ASSERT_THAT_EXPECTED(
47       manager.UnpackTagsData(input, 1),
48       llvm::FailedWithMessage(
49           "Packed tag data size does not match expected number of tags. "
50           "Expected 1 tag(s) for 1 granule(s), got 2 tag(s)."));
51 
52   // By default, we don't check number of tags
53   llvm::Expected<std::vector<lldb::addr_t>> got_zero =
54       manager.UnpackTagsData(input);
55   ASSERT_THAT_EXPECTED(got_zero, llvm::Succeeded());
56   ASSERT_THAT(expected, testing::ContainerEq(*got));
57 
58   // Which is the same as granules=0
59   got_zero = manager.UnpackTagsData(input, 0);
60   ASSERT_THAT_EXPECTED(got_zero, llvm::Succeeded());
61   ASSERT_THAT(expected, testing::ContainerEq(*got));
62 }
63 
64 TEST(MemoryTagManagerAArch64MTETest, PackTags) {
65   MemoryTagManagerAArch64MTE manager;
66 
67   // Error for tag out of range
68   llvm::Expected<std::vector<uint8_t>> invalid_tag_err =
69       manager.PackTags({0x10});
70   ASSERT_THAT_EXPECTED(
71       invalid_tag_err,
72       llvm::FailedWithMessage(
73           "Found tag 0x10 which is > max MTE tag value of 0xf."));
74 
75   // 0xf here is the max tag value that we can pack
76   std::vector<lldb::addr_t> tags{0, 1, 0xf};
77   std::vector<uint8_t> expected{0, 1, 0xf};
78   llvm::Expected<std::vector<uint8_t>> packed = manager.PackTags(tags);
79   ASSERT_THAT_EXPECTED(packed, llvm::Succeeded());
80   ASSERT_THAT(expected, testing::ContainerEq(*packed));
81 }
82 
83 TEST(MemoryTagManagerAArch64MTETest, UnpackTagsFromCoreFileSegment) {
84   MemoryTagManagerAArch64MTE manager;
85   // This is our fake segment data where tags are compressed as 2 4 bit tags
86   // per byte.
87   std::vector<uint8_t> tags_data;
88   MemoryTagManager::CoreReaderFn reader =
89       [&tags_data](lldb::offset_t offset, size_t length, void *dst) {
90         std::memcpy(dst, tags_data.data() + offset, length);
91         return length;
92       };
93 
94   // Zero length is ok.
95   std::vector<lldb::addr_t> tags =
96       manager.UnpackTagsFromCoreFileSegment(reader, 0, 0, 0, 0);
97   ASSERT_EQ(tags.size(), (size_t)0);
98 
99   // In the simplest case we read 2 tags which are in the same byte.
100   tags_data.push_back(0x21);
101   // The least significant bits are the first tag in memory.
102   std::vector<lldb::addr_t> expected{1, 2};
103   tags = manager.UnpackTagsFromCoreFileSegment(reader, 0, 0, 0, 32);
104   ASSERT_THAT(expected, testing::ContainerEq(tags));
105 
106   // If we read just one then it will have to trim off the second one.
107   expected = std::vector<lldb::addr_t>{1};
108   tags = manager.UnpackTagsFromCoreFileSegment(reader, 0, 0, 0, 16);
109   ASSERT_THAT(expected, testing::ContainerEq(tags));
110 
111   // If we read the second tag only then the first one must be trimmed.
112   expected = std::vector<lldb::addr_t>{2};
113   tags = manager.UnpackTagsFromCoreFileSegment(reader, 0, 0, 16, 16);
114   ASSERT_THAT(expected, testing::ContainerEq(tags));
115 
116   // This trimming logic applies if you read a larger set of tags.
117   tags_data = std::vector<uint8_t>{0x21, 0x43, 0x65, 0x87};
118 
119   // Trailing tag should be trimmed.
120   expected = std::vector<lldb::addr_t>{1, 2, 3};
121   tags = manager.UnpackTagsFromCoreFileSegment(reader, 0, 0, 0, 48);
122   ASSERT_THAT(expected, testing::ContainerEq(tags));
123 
124   // Leading tag should be trimmed.
125   expected = std::vector<lldb::addr_t>{2, 3, 4};
126   tags = manager.UnpackTagsFromCoreFileSegment(reader, 0, 0, 16, 48);
127   ASSERT_THAT(expected, testing::ContainerEq(tags));
128 
129   // Leading and trailing trimmmed.
130   expected = std::vector<lldb::addr_t>{2, 3, 4, 5};
131   tags = manager.UnpackTagsFromCoreFileSegment(reader, 0, 0, 16, 64);
132   ASSERT_THAT(expected, testing::ContainerEq(tags));
133 
134   // The address given is an offset into the whole file so the address requested
135   // from the reader should be beyond that.
136   tags_data = std::vector<uint8_t>{0xFF, 0xFF, 0x21, 0x43, 0x65, 0x87};
137   expected = std::vector<lldb::addr_t>{1, 2};
138   tags = manager.UnpackTagsFromCoreFileSegment(reader, 0, 2, 0, 32);
139   ASSERT_THAT(expected, testing::ContainerEq(tags));
140 
141   // addr is a virtual address that we expect to be >= the tag segment's
142   // starting virtual address. So again an offset must be made from the
143   // difference.
144   expected = std::vector<lldb::addr_t>{3, 4};
145   tags = manager.UnpackTagsFromCoreFileSegment(reader, 32, 2, 64, 32);
146   ASSERT_THAT(expected, testing::ContainerEq(tags));
147 }
148 
149 TEST(MemoryTagManagerAArch64MTETest, GetLogicalTag) {
150   MemoryTagManagerAArch64MTE manager;
151 
152   // Set surrounding bits to check shift is correct
153   ASSERT_EQ((lldb::addr_t)0, manager.GetLogicalTag(0xe0e00000ffffffff));
154   // Max tag value
155   ASSERT_EQ((lldb::addr_t)0xf, manager.GetLogicalTag(0x0f000000ffffffff));
156   ASSERT_EQ((lldb::addr_t)2, manager.GetLogicalTag(0x02000000ffffffff));
157 }
158 
159 TEST(MemoryTagManagerAArch64MTETest, ExpandToGranule) {
160   MemoryTagManagerAArch64MTE manager;
161   // Reading nothing, no alignment needed
162   ASSERT_EQ(
163       MemoryTagManagerAArch64MTE::TagRange(0, 0),
164       manager.ExpandToGranule(MemoryTagManagerAArch64MTE::TagRange(0, 0)));
165 
166   // Ranges with 0 size are unchanged even if address is non 0
167   // (normally 0x1234 would be aligned to 0x1230)
168   ASSERT_EQ(
169       MemoryTagManagerAArch64MTE::TagRange(0x1234, 0),
170       manager.ExpandToGranule(MemoryTagManagerAArch64MTE::TagRange(0x1234, 0)));
171 
172   // Ranges already aligned don't change
173   ASSERT_EQ(
174       MemoryTagManagerAArch64MTE::TagRange(0x100, 64),
175       manager.ExpandToGranule(MemoryTagManagerAArch64MTE::TagRange(0x100, 64)));
176 
177   // Any read of less than 1 granule is rounded up to reading 1 granule
178   ASSERT_EQ(
179       MemoryTagManagerAArch64MTE::TagRange(0, 16),
180       manager.ExpandToGranule(MemoryTagManagerAArch64MTE::TagRange(0, 1)));
181 
182   // Start address is aligned down, and length modified accordingly
183   // Here bytes 8 through 24 straddle 2 granules. So the resulting range starts
184   // at 0 and covers 32 bytes.
185   ASSERT_EQ(
186       MemoryTagManagerAArch64MTE::TagRange(0, 32),
187       manager.ExpandToGranule(MemoryTagManagerAArch64MTE::TagRange(8, 16)));
188 
189   // Here only the size of the range needs aligning
190   ASSERT_EQ(
191       MemoryTagManagerAArch64MTE::TagRange(16, 32),
192       manager.ExpandToGranule(MemoryTagManagerAArch64MTE::TagRange(16, 24)));
193 
194   // Start and size need aligning here but we only need 1 granule to cover it
195   ASSERT_EQ(
196       MemoryTagManagerAArch64MTE::TagRange(16, 16),
197       manager.ExpandToGranule(MemoryTagManagerAArch64MTE::TagRange(18, 4)));
198 }
199 
200 static MemoryRegionInfo MakeRegionInfo(lldb::addr_t base, lldb::addr_t size,
201                                        bool tagged) {
202   return MemoryRegionInfo(
203       MemoryRegionInfo::RangeType(base, size), MemoryRegionInfo::eYes,
204       MemoryRegionInfo::eYes, MemoryRegionInfo::eYes, MemoryRegionInfo::eNo,
205       MemoryRegionInfo::eYes, ConstString(), MemoryRegionInfo::eNo, 0,
206       /*memory_tagged=*/
207       tagged ? MemoryRegionInfo::eYes : MemoryRegionInfo::eNo,
208       MemoryRegionInfo::eDontKnow, MemoryRegionInfo::eDontKnow);
209 }
210 
211 TEST(MemoryTagManagerAArch64MTETest, MakeTaggedRange) {
212   MemoryTagManagerAArch64MTE manager;
213   MemoryRegionInfos memory_regions;
214 
215   // No regions means no tagged regions, error
216   ASSERT_THAT_EXPECTED(
217       manager.MakeTaggedRange(0, 0x10, memory_regions),
218       llvm::FailedWithMessage(
219           "Address range 0x0:0x10 is not in a memory tagged region"));
220 
221   // Alignment is done before checking regions.
222   // Here 1 is rounded up to the granule size of 0x10.
223   ASSERT_THAT_EXPECTED(
224       manager.MakeTaggedRange(0, 1, memory_regions),
225       llvm::FailedWithMessage(
226           "Address range 0x0:0x10 is not in a memory tagged region"));
227 
228   // Range must not be inverted
229   ASSERT_THAT_EXPECTED(
230       manager.MakeTaggedRange(1, 0, memory_regions),
231       llvm::FailedWithMessage(
232           "End address (0x0) must be greater than the start address (0x1)"));
233 
234   // The inversion check ignores tags in the addresses (MTE tags start at bit
235   // 56).
236   ASSERT_THAT_EXPECTED(
237       manager.MakeTaggedRange((lldb::addr_t)1 << 56,
238                               ((lldb::addr_t)2 << 56) + 0x10, memory_regions),
239       llvm::FailedWithMessage(
240           "Address range 0x0:0x10 is not in a memory tagged region"));
241 
242   // Adding a single region to cover the whole range
243   memory_regions.push_back(MakeRegionInfo(0, 0x1000, true));
244 
245   // Range can have different tags for begin and end
246   // (which would make it look inverted if we didn't remove them)
247   // Note that range comes back with an untagged base and alginment
248   // applied.
249   MemoryTagManagerAArch64MTE::TagRange expected_range(0x0, 0x10);
250   llvm::Expected<MemoryTagManagerAArch64MTE::TagRange> got =
251       manager.MakeTaggedRange(0x0f00000000000000, 0x0e00000000000001,
252                               memory_regions);
253   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
254   ASSERT_EQ(*got, expected_range);
255 
256   // Error if the range isn't within any region
257   ASSERT_THAT_EXPECTED(
258       manager.MakeTaggedRange(0x1000, 0x1010, memory_regions),
259       llvm::FailedWithMessage(
260           "Address range 0x1000:0x1010 is not in a memory tagged region"));
261 
262   // Error if the first part of a range isn't tagged
263   memory_regions.clear();
264   const char *err_msg =
265       "Address range 0x0:0x1000 is not in a memory tagged region";
266 
267   // First because it has no region entry
268   memory_regions.push_back(MakeRegionInfo(0x10, 0x1000, true));
269   ASSERT_THAT_EXPECTED(manager.MakeTaggedRange(0, 0x1000, memory_regions),
270                        llvm::FailedWithMessage(err_msg));
271 
272   // Then because the first region is untagged
273   memory_regions.push_back(MakeRegionInfo(0, 0x10, false));
274   ASSERT_THAT_EXPECTED(manager.MakeTaggedRange(0, 0x1000, memory_regions),
275                        llvm::FailedWithMessage(err_msg));
276 
277   // If we tag that first part it succeeds
278   memory_regions.back().SetMemoryTagged(MemoryRegionInfo::eYes);
279   expected_range = MemoryTagManagerAArch64MTE::TagRange(0x0, 0x1000);
280   got = manager.MakeTaggedRange(0, 0x1000, memory_regions);
281   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
282   ASSERT_EQ(*got, expected_range);
283 
284   // Error if the end of a range is untagged
285   memory_regions.clear();
286 
287   // First because it has no region entry
288   memory_regions.push_back(MakeRegionInfo(0, 0xF00, true));
289   ASSERT_THAT_EXPECTED(manager.MakeTaggedRange(0, 0x1000, memory_regions),
290                        llvm::FailedWithMessage(err_msg));
291 
292   // Then because the last region is untagged
293   memory_regions.push_back(MakeRegionInfo(0xF00, 0x100, false));
294   ASSERT_THAT_EXPECTED(manager.MakeTaggedRange(0, 0x1000, memory_regions),
295                        llvm::FailedWithMessage(err_msg));
296 
297   // If we tag the last part it succeeds
298   memory_regions.back().SetMemoryTagged(MemoryRegionInfo::eYes);
299   got = manager.MakeTaggedRange(0, 0x1000, memory_regions);
300   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
301   ASSERT_EQ(*got, expected_range);
302 
303   // Error if the middle of a range is untagged
304   memory_regions.clear();
305 
306   // First because it has no entry
307   memory_regions.push_back(MakeRegionInfo(0, 0x500, true));
308   memory_regions.push_back(MakeRegionInfo(0x900, 0x700, true));
309   ASSERT_THAT_EXPECTED(manager.MakeTaggedRange(0, 0x1000, memory_regions),
310                        llvm::FailedWithMessage(err_msg));
311 
312   // Then because it's untagged
313   memory_regions.push_back(MakeRegionInfo(0x500, 0x400, false));
314   ASSERT_THAT_EXPECTED(manager.MakeTaggedRange(0, 0x1000, memory_regions),
315                        llvm::FailedWithMessage(err_msg));
316 
317   // If we tag the middle part it succeeds
318   memory_regions.back().SetMemoryTagged(MemoryRegionInfo::eYes);
319   got = manager.MakeTaggedRange(0, 0x1000, memory_regions);
320   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
321   ASSERT_EQ(*got, expected_range);
322 }
323 
324 TEST(MemoryTagManagerAArch64MTETest, MakeTaggedRanges) {
325   MemoryTagManagerAArch64MTE manager;
326   MemoryRegionInfos memory_regions;
327 
328   // Note that MakeTaggedRanges takes start/end address.
329   // Whereas TagRanges and regions take start address and size.
330 
331   // Range must not be inverted
332   ASSERT_THAT_EXPECTED(
333       manager.MakeTaggedRanges(1, 0, memory_regions),
334       llvm::FailedWithMessage(
335           "End address (0x0) must be greater than the start address (0x1)"));
336 
337   // We remove tags before doing the inversion check, so this is not an error.
338   // Also no regions means no tagged regions returned.
339   // (bit 56 is where MTE tags begin)
340   llvm::Expected<std::vector<MemoryTagManager::TagRange>> got =
341       manager.MakeTaggedRanges((lldb::addr_t)2 << 56,
342                                ((lldb::addr_t)1 << 56) + 0x10, memory_regions);
343   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
344   ASSERT_EQ(*got, std::vector<MemoryTagManager::TagRange>{});
345 
346   // Cover whole range, untagged. No ranges returned.
347   memory_regions.push_back(MakeRegionInfo(0, 0x20, false));
348   got = manager.MakeTaggedRanges(0, 0x20, memory_regions);
349   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
350   ASSERT_EQ(*got, std::vector<MemoryTagManager::TagRange>{});
351 
352   // Make the region tagged and it'll be the one range returned.
353   memory_regions.back().SetMemoryTagged(MemoryRegionInfo::eYes);
354   got = manager.MakeTaggedRanges(0, 0x20, memory_regions);
355   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
356   ASSERT_EQ(*got, std::vector<MemoryTagManager::TagRange>{
357                       MemoryTagManager::TagRange(0, 0x20)});
358 
359   // This region will be trimmed if it's larger than the whole range.
360   memory_regions.clear();
361   memory_regions.push_back(MakeRegionInfo(0, 0x40, true));
362   got = manager.MakeTaggedRanges(0x10, 0x30, memory_regions);
363   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
364   ASSERT_EQ(*got, std::vector<MemoryTagManager::TagRange>{
365                       MemoryTagManager::TagRange(0x10, 0x20)});
366 
367   memory_regions.clear();
368 
369   // For the following tests we keep the input regions
370   // in ascending order as MakeTaggedRanges expects.
371 
372   // Only start of range is tagged, only that is returned.
373   // Start the region just before the requested range to check
374   // we limit the result to the requested range.
375   memory_regions.push_back(MakeRegionInfo(0, 0x20, true));
376   got = manager.MakeTaggedRanges(0x10, 0x100, memory_regions);
377   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
378   ASSERT_EQ(*got, std::vector<MemoryTagManager::TagRange>{
379                       MemoryTagManager::TagRange(0x10, 0x10)});
380 
381   // Add a tagged region at the end, now we get both
382   // and the middle is untagged.
383   // <tagged: [0x0, 0x20)>
384   // <...>
385   // <tagged: [0xE0, 0x120)>
386   // The range added here is deliberately over the end of the
387   // requested range to show that we trim the end.
388   memory_regions.push_back(MakeRegionInfo(0xE0, 0x40, true));
389   got = manager.MakeTaggedRanges(0x10, 0x110, memory_regions);
390   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
391 
392   std::vector<MemoryTagManager::TagRange> expected{
393       MemoryTagManager::TagRange(0x10, 0x10),
394       MemoryTagManager::TagRange(0xE0, 0x30)};
395   ASSERT_EQ(*got, expected);
396 
397   // Now add a middle tagged region.
398   // <tagged: [0x0, 0x20)>
399   // <...>
400   // <tagged: [0x90, 0xB0)>
401   // <...>
402   // <tagged: [0xE0, 0x120)>
403   memory_regions.insert(std::next(memory_regions.begin()),
404                         MakeRegionInfo(0x90, 0x20, true));
405 
406   // As the given regions are in ascending order, the resulting
407   // tagged ranges are also. So this new range goes in the middle.
408   expected.insert(std::next(expected.begin()),
409                   MemoryTagManager::TagRange(0x90, 0x20));
410   got = manager.MakeTaggedRanges(0x10, 0x110, memory_regions);
411   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
412   ASSERT_EQ(*got, expected);
413 
414   // Then if we add untagged regions in between the tagged,
415   // the output should stay the same.
416   // <tagged:   [0x0, 0x20)>
417   // <untagged: [0x20, 0x90)>
418   // <tagged:   [0x90, 0xB0)>
419   // <untagged: [0xB0, 0xE0)>
420   // <tagged:   [0xE0, 0x120)>
421   memory_regions.insert(std::next(memory_regions.begin()),
422                         MakeRegionInfo(0x20, 0x70, false));
423   memory_regions.insert(std::prev(memory_regions.end()),
424                         MakeRegionInfo(0xB0, 0x30, false));
425   got = manager.MakeTaggedRanges(0x10, 0x110, memory_regions);
426   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
427   ASSERT_EQ(*got, expected);
428 
429   // Finally check that we handle only having the end of the range.
430   memory_regions.clear();
431   expected.clear();
432 
433   memory_regions.push_back(MakeRegionInfo(0x100, 0x10, true));
434   expected.push_back(MemoryTagManager::TagRange(0x100, 0x10));
435   got = manager.MakeTaggedRanges(0x10, 0x110, memory_regions);
436   ASSERT_THAT_EXPECTED(got, llvm::Succeeded());
437   ASSERT_EQ(*got, expected);
438 }
439 
440 TEST(MemoryTagManagerAArch64MTETest, RemoveTagBits) {
441   MemoryTagManagerAArch64MTE manager;
442 
443   ASSERT_EQ(0, 0);
444   // Removes the whole top byte
445   ASSERT_EQ((lldb::addr_t)0x00ffeedd11223344,
446             manager.RemoveTagBits(0x00ffeedd11223344));
447   ASSERT_EQ((lldb::addr_t)0x0000000000000000,
448             manager.RemoveTagBits(0xff00000000000000));
449   ASSERT_EQ((lldb::addr_t)0x0055555566666666,
450             manager.RemoveTagBits(0xee55555566666666));
451 }
452 
453 TEST(MemoryTagManagerAArch64MTETest, AddressDiff) {
454   MemoryTagManagerAArch64MTE manager;
455 
456   ASSERT_EQ(0, manager.AddressDiff(0, 0));
457   // Result is signed
458   ASSERT_EQ(10, manager.AddressDiff(10, 0));
459   ASSERT_EQ(-10, manager.AddressDiff(0, 10));
460   // Anything in the top byte is ignored
461   ASSERT_EQ(0, manager.AddressDiff(0x2211222233334444, 0x3311222233334444));
462   ASSERT_EQ(-32, manager.AddressDiff(0x5511222233334400, 0x4411222233334420));
463   ASSERT_EQ(65, manager.AddressDiff(0x9911222233334441, 0x6611222233334400));
464 }
465 
466 // Helper to check that repeating "tags" over "range" gives you
467 // "expected_tags".
468 static void
469 test_repeating_tags(const std::vector<lldb::addr_t> &tags,
470                     MemoryTagManagerAArch64MTE::TagRange range,
471                     const std::vector<lldb::addr_t> &expected_tags) {
472   MemoryTagManagerAArch64MTE manager;
473   llvm::Expected<std::vector<lldb::addr_t>> tags_or_err =
474       manager.RepeatTagsForRange(tags, range);
475   ASSERT_THAT_EXPECTED(tags_or_err, llvm::Succeeded());
476   ASSERT_THAT(expected_tags, testing::ContainerEq(*tags_or_err));
477 }
478 
479 TEST(MemoryTagManagerAArch64MTETest, RepeatTagsForRange) {
480   MemoryTagManagerAArch64MTE manager;
481 
482   // Must have some tags if your range is not empty
483   llvm::Expected<std::vector<lldb::addr_t>> no_tags_err =
484       manager.RepeatTagsForRange({},
485                                  MemoryTagManagerAArch64MTE::TagRange{0, 16});
486   ASSERT_THAT_EXPECTED(
487       no_tags_err, llvm::FailedWithMessage(
488                        "Expected some tags to cover given range, got zero."));
489 
490   // If the range is empty, you get no tags back
491   test_repeating_tags({1, 2, 3}, MemoryTagManagerAArch64MTE::TagRange{0, 0},
492                       {});
493   // And you don't need tags for an empty range
494   test_repeating_tags({}, MemoryTagManagerAArch64MTE::TagRange{0, 0}, {});
495 
496   // A single tag will just be multiplied as many times as needed
497   test_repeating_tags({5}, MemoryTagManagerAArch64MTE::TagRange{0, 16}, {5});
498   test_repeating_tags({6}, MemoryTagManagerAArch64MTE::TagRange{0, 32}, {6, 6});
499 
500   // If you've got as many tags as granules, it's a roundtrip
501   test_repeating_tags({7, 8}, MemoryTagManagerAArch64MTE::TagRange{0, 32},
502                       {7, 8});
503 
504   // If you've got fewer tags than granules, they repeat. Exactly or partially
505   // as needed.
506   test_repeating_tags({7, 8}, MemoryTagManagerAArch64MTE::TagRange{0, 64},
507                       {7, 8, 7, 8});
508   test_repeating_tags({7, 8}, MemoryTagManagerAArch64MTE::TagRange{0, 48},
509                       {7, 8, 7});
510 
511   // If you've got more tags than granules you get back only those needed
512   test_repeating_tags({1, 2, 3, 4}, MemoryTagManagerAArch64MTE::TagRange{0, 32},
513                       {1, 2});
514 }
515