[scudo] Relax the memalign test

[cryptoad]

Summary

Now that we are not rounding up the sizes passed to the secondary allocator,
the memalign test could run out of aligned addresses to return for larger
alignments. We now reduce the size of the quarantine for that test, and
allocate less chunks for the larger alignments.

test/scudo/memalign.cpp

 // RUN: %clang_scudo %s -o %t
 // RUN:     %run %t valid   2>&1
 // RUN: not %run %t invalid 2>&1 | FileCheck %s
 
 // Tests that the various aligned allocation functions work as intended. Also
 // tests for the condition where the alignment is not a power of 2.
 
 #include <assert.h>
 #include <malloc.h>
 #include <stdlib.h>
 #include <string.h>
 
+// Reduce the size of the quarantine, or the test can run out of aligned memory
+// on 32-bit for the larger alignments.
+extern "C" const char *__scudo_default_options() {
+  return "QuarantineSizeMb=1";
+}
+
 // Sometimes the headers may not have this...
 extern "C" void *aligned_alloc (size_t alignment, size_t size);
 
 int main(int argc, char **argv)
 {
   void *p = nullptr;
   size_t alignment = 1U << 12;
   size_t size = 1U << 12;
 
   assert(argc == 2);
 
   if (!strcmp(argv[1], "valid")) {
     posix_memalign(&p, alignment, size);
     if (!p)
       return 1;
     free(p);
     p = aligned_alloc(alignment, size);
     if (!p)
       return 1;
     free(p);
     // Tests various combinations of alignment and sizes
-    for (int i = (sizeof(void *) == 4) ? 3 : 4; i <= 24; i++) {
+    for (int i = (sizeof(void *) == 4) ? 3 : 4; i < 19; i++) {
       alignment = 1U << i;
       for (int j = 1; j < 33; j++) {
         size = 0x800 * j;
         for (int k = 0; k < 3; k++) {
-          p = memalign(alignment, size - (16 * k));
+          p = memalign(alignment, size - (2 * sizeof(void *) * k));
           if (!p)
             return 1;
           free(p);
         }
       }
     }
+    // For larger alignment, reduce the number of allocations to avoid running
+    // out of potential addresses (on 32-bit).
+    for (int i = 19; i <= 24; i++) {
+      for (int k = 0; k < 3; k++) {
+        p = memalign(alignment, 0x1000 - (2 * sizeof(void *) * k));
+        if (!p)
+          return 1;
+        free(p);
+      }
+    }
   }
   if (!strcmp(argv[1], "invalid")) {
     p = memalign(alignment - 1, size);
     free(p);
   }
   return 0;
 }
 
 // CHECK: ERROR: alignment is not a power of 2