[sanitizer_common] Fix DenseMapCustomTest.DefaultMinReservedSizeTest on SPARC

[ro]

Summary

As described in Issue 53523, the DenseMapCustomTest.DefaultMinReservedSizeTest test FAILs on Solaris/SPARC (both 32 and 64-bit):

/vol/llvm/src/llvm-project/local/compiler-rt/lib/sanitizer_common/tests/sanitizer_dense_map_test.cpp:399: Failure
Expected: (MemorySize) != (Map.getMemorySize()), actual: 8192 vs 8192

This happens because SPARC, unlike many other CPUs, uses an 8kB pagesize.

Fixed by incorporating the pagesize into calculation of ExpectedInitialBucketCount and derived values.

Tested on sparcv9-sun-solaris2.11, amd64-pc-solaris2.11, and x86_64-pc-linux-gnu.

[vitalybuka]

compiler-rt/lib/sanitizer_common/tests/sanitizer_dense_map_test.cpp

413

Just two instances, so I'd rather hardcoded it here.
Either way is fine to me.

[ro]

compiler-rt/lib/sanitizer_common/tests/sanitizer_dense_map_test.cpp

413

I've decided to keep the code as is: it avoids duplication and possible inconsistencies as well as an unexplained magical constant (8).

compiler-rt/lib/sanitizer_common/tests/sanitizer_dense_map_test.cpp

TEST(DenseMapCustomTest, EqualityComparison) {
   DenseMap<int, int> M1({{0, 0}, {1, 2}});
   DenseMap<int, int> M2({{0, 0}, {1, 2}});
   DenseMap<int, int> M3({{0, 0}, {1, 3}});
 
   EXPECT_EQ(M1, M2);
   EXPECT_NE(M1, M3);
 }
 
+const int ExpectedInitialBucketCount = GetPageSizeCached() / /* sizeof(KV) */ 8;
+
 // Test for the default minimum size of a DenseMap
 TEST(DenseMapCustomTest, DefaultMinReservedSizeTest) {
-  // IF THIS VALUE CHANGE, please update InitialSizeTest, InitFromIterator, and
-  // ReserveTest as well!
-  const int ExpectedInitialBucketCount = 512;
   // Formula from DenseMap::getMinBucketToReserveForEntries()
   const int ExpectedMaxInitialEntries = ExpectedInitialBucketCount * 3 / 4 - 1;
 
   DenseMap<int, CountCopyAndMove> Map;
   // Will allocate 64 buckets
   Map.reserve(1);
   unsigned MemorySize = Map.getMemorySize();
   CountCopyAndMove::Copy = 0;

 }
 
 // Make sure creating the map with an initial size of N actually gives us enough
 // buckets to insert N items without increasing allocation size.
 TEST(DenseMapCustomTest, InitialSizeTest) {
   // Test a few different size, 341 is *not* a random choice: we need a value
   // that is 2/3 of a power of two to stress the grow() condition, and the power
   // of two has to be at least 512 because of minimum size allocation in the
-  // DenseMap (see DefaultMinReservedSizeTest). 513 is a value just above the
-  // 512 default init.
-  for (auto Size : {1, 2, 48, 66, 341, 513}) {
+  // DenseMap (see DefaultMinReservedSizeTest).
+  for (auto Size : {1, 2, 48, 66, 341, ExpectedInitialBucketCount + 1}) {
     DenseMap<int, CountCopyAndMove> Map(Size);
     unsigned MemorySize = Map.getMemorySize();
     CountCopyAndMove::Copy = 0;
     CountCopyAndMove::Move = 0;
     for (int i = 0; i < Size; ++i) {
       detail::DenseMapPair<int, CountCopyAndMove> KV;
       KV.first = i;
       Map.insert(move(KV));

 }
 
 // Make sure reserve actually gives us enough buckets to insert N items
 // without increasing allocation size.
 TEST(DenseMapCustomTest, ReserveTest) {
   // Test a few different size, 341 is *not* a random choice: we need a value
   // that is 2/3 of a power of two to stress the grow() condition, and the power
   // of two has to be at least 512 because of minimum size allocation in the
-  // DenseMap (see DefaultMinReservedSizeTest). 513 is a value just above the
-  // 512 default init.
-  for (auto Size : {1, 2, 48, 66, 341, 513}) {
+  // DenseMap (see DefaultMinReservedSizeTest).
+  for (auto Size : {1, 2, 48, 66, 341, ExpectedInitialBucketCount + 1}) {
     DenseMap<int, CountCopyAndMove> Map;
     Map.reserve(Size);
     unsigned MemorySize = Map.getMemorySize();
     CountCopyAndMove::Copy = 0;
     CountCopyAndMove::Move = 0;
     for (int i = 0; i < Size; ++i) {
       detail::DenseMapPair<int, CountCopyAndMove> KV;
       KV.first = i;