Refactor malloc debug.

Changes
- Refactor the code so that only guards require creating a special header
  for every pointer allocated.
- Store only a single copy of every backtrace. This saves memory so that
  turning on the backtrace option doesn't result in 10X memory usage.
- Added new option track_allocs that only verifies pointers are valid for
  free/malloc_usable_size/realloc.
- Remove suffix from test names.
- Add the TRACK_ALLOCS options to all guard options.
- Add new option verify_pointers that is a lightweight way to verify
  pointers that are passed to allocation routines.
- Do auto-formatting of the code.
- Updated documentation for all of these changes.

Bug: 74361929

Test: Ran unit tests.
Test: Ran libmemunreachable unit tests.
Test: Ran an app with backtrace enabled.

Change-Id: I3246c48ae4f9811f64622d90d0a9b4d9d818702c

1 files changed, 0 insertions, 7 deletions

diff --git a/libc/malloc_debug/malloc_debug.h b/libc/malloc_debug/malloc_debug.h
index 18a6c2c7f..ac210e246 100644
--- a/libc/malloc_debug/malloc_debug.h
+++ b/libc/malloc_debug/malloc_debug.h
@@ -37,13 +37,10 @@
 // part of the header does not exist, the other parts of the header
 // will still be in this order.
 //   Header          (Required)
-//   BacktraceHeader (Optional: For the allocation backtrace)
 //   uint8_t data    (Optional: Front guard, will be a multiple of MINIMUM_ALIGNMENT_BYTES)
 //   allocation data
 //   uint8_t data    (Optional: End guard)
 //
-// If backtracing is enabled, then both BacktraceHeaders will be present.
-//
 // In the initialization function, offsets into the header will be set
 // for each different header location. The offsets are always from the
 // beginning of the Header section.
@@ -52,10 +49,6 @@ struct Header {
   void* orig_pointer;
   size_t size;
   size_t usable_size;
-  size_t real_size() const { return size & ~(1U << 31); }
-  void set_zygote_child_alloc() { size |= 1U << 31; }
-  bool zygote_child_alloc() const { return size & (1U << 31); }
-  static size_t max_size() { return (1U << 31) - 1; }
 } __attribute__((packed));
 
 struct BacktraceHeader {