[sanitizers][windows] Rtl-Heap Interception and tests

[mcgov]

Summary

Adds interceptors for Rtl(Allocate|Free|Size|ReAllocate)Heap family of functions on windows. Hooking these requires more thorough hooking of the Heap(Alloc|Free|Size|ReAlloc) family. This feature is hidden behind a CMake configuration variable since it will incur a performance penalty due to many calls to RtlValidateHeap and HeapValidate.

The tests that exercise this code are also hidden with an environment variable that will add an available feature. This is a hack since I'm not sure the best way to turn these on and off based on the cmake configuration. I am super open to suggestions on a better way to do this :)

[mcgov]

updating to mask RTL interception from x64 (not supported yet)

[mcgov]

Modifying to make this option selectable at runtime. This makes it cleaner, without needing config and env var hacks

[mcgov]

Switches CMake config and environment variable to turn tests on to an ASAN_OPTIONS runtime variable. This makes the activation and testing cleaner, as well as the code itself.

[mcgov]

@rnk @vitalybuka @mstorsjo ready for review :)

[vitalybuka]

compiler-rt/lib/asan/asan_malloc_win.cc

53

can you please upload the patch with "arc" tool, otherwise context is not visible

209

Not sure I understand this "if".
Can we get here when windows_hook_rtl_allocators==false?
If true, I don't see much difference after asan_inited set to true.

211

can you please clang-format the patch?

218

I'd expect this check is needed unconditionally, we can get to asan_malloc_usable_size even "if-then" about was executed.

462

Isn't better to use REAL in cases above instead of CHECK(Flags...) ?

[mcgov]

compiler-rt/lib/asan/asan_malloc_win.cc

53

will do

209

These if's are handling some edge cases when you hook the RTL allocators. There are some allocations which will occur before interception happens, so you have to check where the allocation came from.

I agree these look pretty gross and aren't super clear. I'll see if I can clean it up or write some comments to make them obvious.

211

I have my editor set to format on save/paste but something must have gone wrong. Will make sure the new sections are formatted properly

218

Oh good point, I'll check assertions again file-wide.

462

I need more context on what you mean here, where would it be better?

[mcgov]

Code cleaning, adding comments for clarity

[mcgov]

addressing comments from @vitalybuka

compiler-rt/lib/asan/asan_malloc_win.cc

209

I've cleaned these up, they look a little weird at first but the new code makes sure to split up unsupported flags at allocation time when the runtime flag is set. In that case it is enough to check who owns the allocation, since the user can allocate a memory section without the unsupported flags but then use them on a later call to HeapSize or HeapReAlloc. When the RTL interception is turned on it's enough to just check who owns it, since if the user wants to use HEAP_NO_SERIALIZE on Free or Size it will just get ignored in the event ASAN owns the allocation. If the allocation is passed into the RTL library it will pass the flag through.

If the flag is turned off we keep the original behavior of asserting on those illegal flags, since there is no falling back to the original allocator in that version.

That's a lot, does that make sense or am I talking myself into garbage lol

[vitalybuka]

compiler-rt/lib/asan/asan_malloc_win.cc

218

this is marked as done, but I don't see a difference.

I expected something like:

if (flags()->windows_hook_rtl_allocators) {
  ...
  REAL...
}
CHECK(dwFlags == 0 && "unsupported heap flags");

without else

[mcgov]

compiler-rt/lib/asan/asan_malloc_win.cc

218

Right, I don't think this is actually the behavior that's needed though. It's the same reason as in HeapFree, when the RTL interception is turned on the check for incomaptible flags occurs only on (re)allocation. If the user is trying to pass unsupported flags to Size or Free for an allocation that's owned by the ASAN allocator we still want that size or free to come back to the user code, reguardless of where it lives. It's a weird situation that comes from juggling the original and asan allocator.

[mcgov]

@vitalybuka Heya, not marking as done but need some feedback from you.

[mcgov]

Another bump for review from @rnk or @vitalybuka

The goals of this patch were to enable RTL interception and preserve the current functionality when the option is turned off. This is why there are some weird IF conditions that seem like they should be global. To get the RTL interception to work the way you would expect it required changing some of the ways flags that are passed into the Allocate/Free/ReAllocate/Size functions are handled. This may not be worth much since you can't see the test results (for now) but we have been using this patch internally for a few months now :-)

[vitalybuka]

.gitignore

48 ↗

(On Diff #205885)

Separate patch?

compiler-rt/lib/asan/asan_malloc_win.cc

39

Why these and new constants are macros and not regular consts or constexpr?

277

Leave this to compiler?

template<class ReAllocFunction...> 
static void* SharedReAlloc(ReAllocFunction reallocFunc, ...

280

this should be static on in namespace {}

280

void* SharedReAlloc?

462

Ignore my comment, now I understand your approach.

compiler-rt/lib/asan/asan_win.cc

181

Still shows "Context not available."

218

could you please use consts?

[mcgov]

addressing comments from @vitalybuka
changing macros to constexpr
moving private stuff into asan namespace

[mcgov]

Addressing comments

.gitignore

48 ↗

(On Diff #205885)

Sure, I can wrap this up with some other msvc host compat stuff (coming soon)

compiler-rt/lib/asan/asan_malloc_win.cc

39

No reason, I'll switch them

277

I did try this solution first, but we're stuck here because the template parameters would end up being pointers that are not compile-time constants. The arguments that are being pointed to are not the regular HeapAlloc address (which get patched), it's the pointers to the REAL(HeapAlloc) which are not known until hooking is finished.

The templated solution is cleaner but doesn't work in this situation. I will address these other concerns though it should be in the namespace. Thank you for the feedback!

compiler-rt/lib/asan/asan_win.cc

218

been reading too much old win32 code sorry 😂
will fix!

[mcgov]

updated consexpr and namespace issue

[mcgov]

@rnk @vitalybuka

Just pinging again for review to land this if possible.

[rnk]

I reviewed the code and mostly came up with surface formatting issues. Functionally I think it looks good and the only way to really find out if it works is to ship it. :) So, I think we should fix the surface issues and try to move forward with that.

compiler-rt/lib/asan/asan_malloc_win.cc

275

Please capitalize the type name of the enum, so AllocationOwnership.

286

This is used in one place, I would sink it down to the use.

290

This is only used if RTL allocator hooking is enabled, I'd sink it into the if.

compiler-rt/lib/asan/asan_win.cc

233

I think it would be simpler to drop this check and always do the IsTlsInitialized() check. I understand that adding the new heap interceptors is what causes us to run code prior to TLS initialization, but in the future ASan could change again in some other way that causes us to clal ASanTSDGet early and removing an if and defending against that possibility seems good.

Also, this isn't indented correctly, please fix that before committing.

299

There should be a space between the ){. I'd recommend using git-clang-format or some other tool to run clang-format to fix these minor issues.

[vitalybuka]

In D62927#1568926, @rnk wrote:

I reviewed the code and mostly came up with surface formatting issues. Functionally I think it looks good and the only way to really find out if it works is to ship it. :) So, I think we should fix the surface issues and try to move forward with that.

LGTM, @rnk please accept when ready

[mcgov]

Updating for RNK comments

[rnk]

lgtm

[jfb]

Reverted in https://reviews.llvm.org/rL365384

because of: http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/28842/steps/build%20stage%201/logs/stdio

/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/projects/compiler-rt/lib/asan/asan_malloc_win.cc:23:2: error: #error "Missing arch or unsupported platform for Windows."
 #error "Missing arch or unsupported platform for Windows."
  ^~~~~
/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/projects/compiler-rt/lib/asan/asan_malloc_win.cc:25:10: fatal error: heapapi.h: No such file or directory
 #include <heapapi.h>
          ^~~~~~~~~~~
compilation terminated.
[39/1151] Building CXX object projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_debugging.cc.o
[40/1151] Building CXX object projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_malloc_win.cc.o
FAILED: projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_malloc_win.cc.o 
/usr/bin/c++  -D_DEBUG -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Iprojects/compiler-rt/lib/asan -I/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/projects/compiler-rt/lib/asan -Iinclude -I/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/include -I/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/projects/compiler-rt/lib/asan/.. -fPIC -fvisibility-inlines-hidden -Werror=date-time -std=c++11 -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -fdiagnostics-color -ffunction-sections -fdata-sections -Wall -std=c++11 -Wno-unused-parameter -O2    -UNDEBUG  -m64 -fPIC -fno-builtin -fno-exceptions -fomit-frame-pointer -funwind-tables -fno-stack-protector -fvisibility=hidden -fno-lto -O3 -g -Wno-variadic-macros -Wno-non-virtual-dtor -fno-rtti -MD -MT projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_malloc_win.cc.o -MF projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_malloc_win.cc.o.d -o projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_malloc_win.cc.o -c /home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/projects/compiler-rt/lib/asan/asan_malloc_win.cc
/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/projects/compiler-rt/lib/asan/asan_malloc_win.cc:23:2: error: #error "Missing arch or unsupported platform for Windows."
 #error "Missing arch or unsupported platform for Windows."
  ^~~~~
/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/projects/compiler-rt/lib/asan/asan_malloc_win.cc:25:10: fatal error: heapapi.h: No such file or directory
 #include <heapapi.h>
          ^~~~~~~~~~~

[rnk]

In D62927#1574273, @jfb wrote:

Reverted in https://reviews.llvm.org/rL365384

because of: http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/28842/steps/build%20stage%201/logs/stdio

/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/projects/compiler-rt/lib/asan/asan_malloc_win.cc:23:2: error: #error "Missing arch or unsupported platform for Windows."
 #error "Missing arch or unsupported platform for Windows."
  ^~~~~
/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/projects/compiler-rt/lib/asan/asan_malloc_win.cc:25:10: fatal error: heapapi.h: No such file or directory
 #include <heapapi.h>
          ^~~~~~~~~~~

This should be easy to fix, the entire asan_malloc_win.cc file should be encapsulated in the #if SANITIZER_WINDOWS block, including this.

I would recommend setting up a build and test environment on Linux to flush out these issues prior to committing in the future, since ASan is very platform sensitive. Once you get that working, feel free to reland when you get a chance.

[rnk]

I noticed the new tests also failed on the sanitizer-windows bot:
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/48066/steps/stage%201%20check/logs/stdio

I haven't looked into it much, but it would be good to investigate that before trying again.

[mstorsjo]

Sorry for not testing out this commit until it hit the tree and not commenting on this before. This one turned out to break MinGW builds for a few different reasons, that I'll comment on inline.

Unrelated point: Please close the review on/after committing; this is easily handled by mentioning the review in the commit message in the form Differential Revision: https://reviews.llvm.org/D62927. In this case I was surprised why this could have broken anything as the review still wasn't closed.

If fixing these cases with the issues I'm pointing out is too cumbersome, I wouldn't mind adding a large #ifndef __MINGW32__ around the new code. But the release branch is approaching fast, and I'd like to have address sanitizer at least buildable for MinGW in the release (even though issues can be fixed after the branch as well) - having these new interceptors usable is less of a deal.

compiler-rt/lib/asan/asan_malloc_win.cc

18

This needs an || defined(__i386__) for MinGW, and same with defined(__x86_64__) below. And changing the #define _X86_ into #define _X86_ 1 avoids a warning about redefinition to a different value.

25

This file implicitly includes a lot of windows specific headers. See the comment below about "Intentionally not including windows.h here"; this brings back the same issue that was fixed earlier by removing the include of windows.h here, in particular errors like these:

compiler-rt/lib/asan/asan_malloc_win.cc:84:6: error: redeclaration of 'free' cannot add 'dllexport' attribute
void free(void *ptr) {
     ^

To avoid this, we need to make sure we don't see any inline function that uses the function free up to this point, when we redefine it with new attributes.

348

In MinGW, min() isn't defined by the headers included so far. I guess that could be considered a MinGW header bug (it's not defined if __cplusplus is defined - fixing that if necessary should hopefully be doable), but the issue mentioned above about explicitly avoiding windows platform headers might also lead to it being unavailable in MSVC style builds.

411

_Frees_ptr_opt_ is not available/defined in MinGW - can it be left out here, or does that cause errors about mismatching attributes in an MSVC build?

[mcgov]

@mrstojo no worries! I'm very new and still learning how to be a good contributor so I appreciate feedback on what I'm doing wrong. I will remove the heapapi include and replace with just the function prototypes I needed along with those constants.

I'm closing this review and will open a new one for the mingw32 changes

compiler-rt/lib/asan/asan_malloc_win.cc

18

Will just yank this, we don't need the full include.

25

Whoops! will just replace with the items I need. We should need the function prototypes so if that's correct I'll just yank them out of the header.

348

no trouble, will replace

411

Nope, will remove this. My guess is this is some static analysis macro actually that resolves to nothing anyway, I just missed this was here since it's defined somewhere in that headerm so it shouldn't hurt anything to remove.

compiler-rt/lib/asan/asan_flags.inc

ASAN_FLAG(int, detect_odr_violation, 2,
           "have different sizes")
 ASAN_FLAG(const char *, suppressions, "", "Suppressions file name.")
 ASAN_FLAG(bool, halt_on_error, true,
           "Crash the program after printing the first error report "
           "(WARNING: USE AT YOUR OWN RISK!)")
 ASAN_FLAG(bool, allocator_frees_and_returns_null_on_realloc_zero, true,
           "realloc(p, 0) is equivalent to free(p) by default (Same as the "
           "POSIX standard). If set to false, realloc(p, 0) will return a "
-          "pointer to an allocated space which can not be used.")
-ASAN_FLAG(bool, verify_asan_link_order, true,
-          "Check position of ASan runtime in library list (needs to be disabled"
-          " when other library has to be preloaded system-wide)")
+          "pointer to an allocated space which can not be used.")
+ASAN_FLAG(bool, verify_asan_link_order, true,
+          "Check position of ASan runtime in library list (needs to be disabled"
+          " when other library has to be preloaded system-wide)")
+ASAN_FLAG(bool, windows_hook_rtl_allocators, false,
+          "(Windows only) enable hooking of Rtl(Allocate|Free|Size|ReAllocate)Heap.")

compiler-rt/lib/asan/asan_malloc_win.cc

 //===-- asan_malloc_win.cc ------------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file is a part of AddressSanitizer, an address sanity checker.
 //
 // Windows-specific malloc interception.
 //===----------------------------------------------------------------------===//
+
+
+#include "sanitizer_common/sanitizer_allocator_interface.h"
+// Need to include defintions for windows heap api functions,
+// these assume windows.h will also be included. This definition
+// fixes an error that's thrown if you only include heapapi.h
+#if defined(_M_IX86)
+#define _X86_
+#elif defined(_M_AMD64)
+#define _AMD64_
+#else
+#error "Missing arch or unsupported platform for Windows."
+#endif
+#include <heapapi.h>
+
 
 #include "sanitizer_common/sanitizer_platform.h"
 #if SANITIZER_WINDOWS
 // Intentionally not including windows.h here, to avoid the risk of
 // pulling in conflicting declarations of these functions. (With mingw-w64,
 // there's a risk of windows.h pulling in stdint.h.)
 typedef int BOOL;
 typedef void *HANDLE;
 typedef const void *LPCVOID;
-typedef void *LPVOID;
-
-#define HEAP_ZERO_MEMORY           0x00000008
-#define HEAP_REALLOC_IN_PLACE_ONLY 0x00000010
-
+typedef void *LPVOID;
+
+constexpr unsigned long HEAP_ALLOCATE_SUPPORTED_FLAGS = (HEAP_ZERO_MEMORY);
+constexpr unsigned long HEAP_ALLOCATE_UNSUPPORTED_FLAGS =
+    (~HEAP_ALLOCATE_SUPPORTED_FLAGS);
+constexpr unsigned long HEAP_FREE_SUPPORTED_FLAGS = (0);
+constexpr unsigned long HEAP_FREE_UNSUPPORTED_FLAGS =
+    (~HEAP_ALLOCATE_SUPPORTED_FLAGS);
+constexpr unsigned long HEAP_REALLOC_SUPPORTED_FLAGS =
+    (HEAP_REALLOC_IN_PLACE_ONLY | HEAP_ZERO_MEMORY);
+constexpr unsigned long HEAP_REALLOC_UNSUPPORTED_FLAGS =
+    (~HEAP_ALLOCATE_SUPPORTED_FLAGS);
 
 #include "asan_allocator.h"
 #include "asan_interceptors.h"
 #include "asan_internal.h"
 #include "asan_stack.h"
 #include "interception/interception.h"
 
 #include <stddef.h>
 
 using namespace __asan;  // NOLINT
 
 // MT: Simply defining functions with the same signature in *.obj
 // files overrides the standard functions in the CRT.
if (new_alloc) {
     free(p);
   }
   return new_alloc;
 }
 
 ALLOCATION_FUNCTION_ATTRIBUTE
 void *_recalloc_base(void *p, size_t n, size_t elem_size) {
   return _recalloc(p, n, elem_size);
-}
-
-ALLOCATION_FUNCTION_ATTRIBUTE
-void *_expand(void *memblock, size_t size) {
-  // _expand is used in realloc-like functions to resize the buffer if possible.
-  // We don't want memory to stand still while resizing buffers, so return 0.
-  return 0;
-}
-
-ALLOCATION_FUNCTION_ATTRIBUTE
-void *_expand_dbg(void *memblock, size_t size) {
-  return _expand(memblock, size);
-}
-
-// TODO(timurrrr): Might want to add support for _aligned_* allocation
-// functions to detect a bit more bugs.  Those functions seem to wrap malloc().
-
-int _CrtDbgReport(int, const char*, int,
-                  const char*, const char*, ...) {
-  ShowStatsAndAbort();
-}
-
-int _CrtDbgReportW(int reportType, const wchar_t*, int,
-                   const wchar_t*, const wchar_t*, ...) {
-  ShowStatsAndAbort();
-}
-
-int _CrtSetReportMode(int, int) {
-  return 0;
-}
-}  // extern "C"
-
-INTERCEPTOR_WINAPI(LPVOID, HeapAlloc, HANDLE hHeap, DWORD dwFlags,
-                   SIZE_T dwBytes) {
-  GET_STACK_TRACE_MALLOC;
-  void *p = asan_malloc(dwBytes, &stack);
-  // Reading MSDN suggests that the *entire* usable allocation is zeroed out.
-  // Otherwise it is difficult to HeapReAlloc with HEAP_ZERO_MEMORY.
-  // https://blogs.msdn.microsoft.com/oldnewthing/20120316-00/?p=8083
-  if (dwFlags == HEAP_ZERO_MEMORY)
-    internal_memset(p, 0, asan_mz_size(p));
-  else
-    CHECK(dwFlags == 0 && "unsupported heap flags");
-  return p;
-}
-
-INTERCEPTOR_WINAPI(BOOL, HeapFree, HANDLE hHeap, DWORD dwFlags, LPVOID lpMem) {
-  CHECK(dwFlags == 0 && "unsupported heap flags");
-  GET_STACK_TRACE_FREE;
-  asan_free(lpMem, &stack, FROM_MALLOC);
-  return true;
-}
-
-INTERCEPTOR_WINAPI(LPVOID, HeapReAlloc, HANDLE hHeap, DWORD dwFlags,
-                   LPVOID lpMem, SIZE_T dwBytes) {
-  GET_STACK_TRACE_MALLOC;
-  GET_CURRENT_PC_BP_SP;
-  (void)sp;
-  // Realloc should never reallocate in place.
-  if (dwFlags & HEAP_REALLOC_IN_PLACE_ONLY)
-    return nullptr;
-  CHECK(dwFlags == 0 && "unsupported heap flags");
-  // HeapReAlloc and HeapAlloc both happily accept 0 sized allocations.
-  // passing a 0 size into asan_realloc will free the allocation.
-  // To avoid this and keep behavior consistent, fudge the size if 0.
-  // (asan_malloc already does this)
-  if (dwBytes == 0)
-    dwBytes = 1;
-  size_t old_size;
-  if (dwFlags & HEAP_ZERO_MEMORY)
-    old_size = asan_malloc_usable_size(lpMem, pc, bp);
-  void *ptr = asan_realloc(lpMem, dwBytes, &stack);
-  if (ptr == nullptr)
-    return nullptr;
-
-  if (dwFlags & HEAP_ZERO_MEMORY) {
-    size_t new_size = asan_malloc_usable_size(ptr, pc, bp);
-    if (old_size < new_size)
-      REAL(memset)(((u8 *)ptr) + old_size, 0, new_size - old_size);
-  }
-  return ptr;
-}
-
-INTERCEPTOR_WINAPI(SIZE_T, HeapSize, HANDLE hHeap, DWORD dwFlags,
-                   LPCVOID lpMem) {
-  CHECK(dwFlags == 0 && "unsupported heap flags");
-  GET_CURRENT_PC_BP_SP;
-  (void)sp;
-  return asan_malloc_usable_size(lpMem, pc, bp);
-}
-
-namespace __asan {
-
-static void TryToOverrideFunction(const char *fname, uptr new_func) {
-  // Failure here is not fatal. The CRT may not be present, and different CRT
-  // versions use different symbols.
-  if (!__interception::OverrideFunction(fname, new_func))
-    VPrintf(2, "Failed to override function %s\n", fname);
-}
-
-void ReplaceSystemMalloc() {
-#if defined(ASAN_DYNAMIC)
-  TryToOverrideFunction("free", (uptr)free);
-  TryToOverrideFunction("_free_base", (uptr)free);
-  TryToOverrideFunction("malloc", (uptr)malloc);
-  TryToOverrideFunction("_malloc_base", (uptr)malloc);
-  TryToOverrideFunction("_malloc_crt", (uptr)malloc);
-  TryToOverrideFunction("calloc", (uptr)calloc);
-  TryToOverrideFunction("_calloc_base", (uptr)calloc);
-  TryToOverrideFunction("_calloc_crt", (uptr)calloc);
-  TryToOverrideFunction("realloc", (uptr)realloc);
-  TryToOverrideFunction("_realloc_base", (uptr)realloc);
-  TryToOverrideFunction("_realloc_crt", (uptr)realloc);
-  TryToOverrideFunction("_recalloc", (uptr)_recalloc);
-  TryToOverrideFunction("_recalloc_base", (uptr)_recalloc);
-  TryToOverrideFunction("_recalloc_crt", (uptr)_recalloc);
-  TryToOverrideFunction("_msize", (uptr)_msize);
-  TryToOverrideFunction("_msize_base", (uptr)_msize);
-  TryToOverrideFunction("_expand", (uptr)_expand);
-  TryToOverrideFunction("_expand_base", (uptr)_expand);
-
-  // Recent versions of ucrtbase.dll appear to be built with PGO and LTCG, which
-  // enable cross-module inlining. This means our _malloc_base hook won't catch
-  // all CRT allocations. This code here patches the import table of
-  // ucrtbase.dll so that all attempts to use the lower-level win32 heap
-  // allocation API will be directed to ASan's heap. We don't currently
-  // intercept all calls to HeapAlloc. If we did, we would have to check on
-  // HeapFree whether the pointer came from ASan of from the system.
-#define INTERCEPT_UCRT_FUNCTION(func)                                         \
-  if (!INTERCEPT_FUNCTION_DLLIMPORT("ucrtbase.dll",                           \
-                                    "api-ms-win-core-heap-l1-1-0.dll", func)) \
-    VPrintf(2, "Failed to intercept ucrtbase.dll import %s\n", #func);
-  INTERCEPT_UCRT_FUNCTION(HeapAlloc);
-  INTERCEPT_UCRT_FUNCTION(HeapFree);
-  INTERCEPT_UCRT_FUNCTION(HeapReAlloc);
-  INTERCEPT_UCRT_FUNCTION(HeapSize);
-#undef INTERCEPT_UCRT_FUNCTION
-#endif
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_expand(void *memblock, size_t size) {
+  // _expand is used in realloc-like functions to resize the buffer if possible.
+  // We don't want memory to stand still while resizing buffers, so return 0.
+  return 0;
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_expand_dbg(void *memblock, size_t size) {
+  return _expand(memblock, size);
+}
+
+// TODO(timurrrr): Might want to add support for _aligned_* allocation
+// functions to detect a bit more bugs.  Those functions seem to wrap malloc().
+
+int _CrtDbgReport(int, const char*, int,
+                  const char*, const char*, ...) {
+  ShowStatsAndAbort();
+}
+
+int _CrtDbgReportW(int reportType, const wchar_t*, int,
+                   const wchar_t*, const wchar_t*, ...) {
+  ShowStatsAndAbort();
+}
+
+int _CrtSetReportMode(int, int) {
+  return 0;
+}
+}  // extern "C"
+
+#define OWNED_BY_RTL(heap, memory) \
+  (!__sanitizer_get_ownership(memory) && HeapValidate(heap, 0, memory))
+
+INTERCEPTOR_WINAPI(SIZE_T, HeapSize, HANDLE hHeap, DWORD dwFlags,
+                   LPCVOID lpMem)
+{
+  // If the RTL allocators are hooked we need to check whether the ASAN
+  // allocator owns the pointer we're about to use. Allocations occur before
+  // interception takes place, so if it is not owned by the RTL heap we can
+  // pass it to the ASAN heap for inspection.
+  if (flags()->windows_hook_rtl_allocators) {
+    if (!asan_inited || OWNED_BY_RTL(hHeap, lpMem))
+      return REAL(HeapSize)(hHeap, dwFlags, lpMem);
+  } else {
+    CHECK(dwFlags == 0 && "unsupported heap flags");
+  }
+  GET_CURRENT_PC_BP_SP;
+  (void)sp;
+  return asan_malloc_usable_size(lpMem, pc, bp);
+}
+
+INTERCEPTOR_WINAPI(LPVOID, HeapAlloc, HANDLE hHeap, DWORD dwFlags,
+                   SIZE_T dwBytes) {
+  // If the ASAN runtime is not initialized, or we encounter an unsupported
+  // flag, fall back to the original allocator.
+  if (flags()->windows_hook_rtl_allocators) {
+    if (UNLIKELY(!asan_inited ||
+                 (dwFlags & HEAP_ALLOCATE_UNSUPPORTED_FLAGS) != 0)) {
+      return REAL(HeapAlloc)(hHeap, dwFlags, dwBytes);
+    }
+  } else {
+    // In the case that we don't hook the rtl allocators,
+    // this becomes an assert since there is no failover to the original
+    // allocator.
+    CHECK((HEAP_ALLOCATE_UNSUPPORTED_FLAGS & dwFlags) != 0 &&
+          "unsupported flags");
+  }
+  GET_STACK_TRACE_MALLOC;
+  void *p = asan_malloc(dwBytes, &stack);
+  // Reading MSDN suggests that the *entire* usable allocation is zeroed out.
+  // Otherwise it is difficult to HeapReAlloc with HEAP_ZERO_MEMORY.
+  // https://blogs.msdn.microsoft.com/oldnewthing/20120316-00/?p=8083
+  if (p && (dwFlags & HEAP_ZERO_MEMORY)) {
+    GET_CURRENT_PC_BP_SP;
+    (void)sp;
+    auto usable_size = asan_malloc_usable_size(p, pc, bp);
+    internal_memset(p, 0, usable_size);
+  }
+  return p;
+}
+
+INTERCEPTOR_WINAPI(BOOL, HeapFree, HANDLE hHeap, DWORD dwFlags, LPVOID lpMem) {
+  // Heap allocations happen before this function is hooked, so we must fall
+  // back to the original function if the pointer is not from the ASAN heap,
+  // or unsupported flags are provided.
+  if (flags()->windows_hook_rtl_allocators) {
+    if (OWNED_BY_RTL(hHeap, lpMem))
+      return REAL(HeapFree)(hHeap, dwFlags, lpMem);
+  } else {
+    CHECK((HEAP_FREE_UNSUPPORTED_FLAGS & dwFlags) != 0 && "unsupported flags");
+  }
+  GET_STACK_TRACE_FREE;
+  asan_free(lpMem, &stack, FROM_MALLOC);
+  return true;
+}
+
+namespace __asan {
+enum allocationOwnership { NEITHER = 0, ASAN = 1, RTL = 2 };
+using AllocFunction = LPVOID(WINAPI *)(HANDLE, DWORD, SIZE_T);
+using ReAllocFunction = LPVOID(WINAPI *)(HANDLE, DWORD, LPVOID, SIZE_T);
+using SizeFunction = SIZE_T(WINAPI *)(HANDLE, DWORD, LPVOID);
+using FreeFunction = BOOL(WINAPI *)(HANDLE, DWORD, LPVOID);
+
+void* SharedReAlloc(ReAllocFunction reallocFunc, SizeFunction heapSizeFunc,
+                     FreeFunction freeFunc, AllocFunction allocFunc,
+                     HANDLE hHeap, DWORD dwFlags, LPVOID lpMem,
+                     SIZE_T dwBytes) {
+  CHECK(reallocFunc && heapSizeFunc && freeFunc && allocFunc);
+  size_t old_usable_size = 0;
+  GET_STACK_TRACE_MALLOC;
+  GET_CURRENT_PC_BP_SP;
+  (void)sp;
+  allocationOwnership ownershipState;
+  if (flags()->windows_hook_rtl_allocators) {
+    bool owned_rtlalloc = false;
+    bool owned_asan = __sanitizer_get_ownership(lpMem);
+
+    if (!owned_asan)
+      owned_rtlalloc = HeapValidate(hHeap, 0, lpMem);
+
+    if (owned_asan && !owned_rtlalloc)
+      ownershipState = ASAN;
+    else if (!owned_asan && owned_rtlalloc)
+      ownershipState = RTL;
+    else if (!owned_asan && !owned_rtlalloc)
+      ownershipState = NEITHER;
+
+    // If this heap block which was allocated before the ASAN
+    // runtime came up, use the real HeapFree function.
+    if (UNLIKELY(!asan_inited)) {
+      return reallocFunc(hHeap, dwFlags, lpMem, dwBytes);
+    }
+    bool only_asan_supported_flags =
+        (HEAP_REALLOC_UNSUPPORTED_FLAGS & dwFlags) == 0;
+
+    if (ownershipState == RTL ||
+        (ownershipState == NEITHER && !only_asan_supported_flags)) {
+      if (only_asan_supported_flags) {
+        // if this is a conversion to ASAN upported flags, transfer this
+        // allocation to the ASAN allocator
+        void *replacement_alloc;
+        if (dwFlags & HEAP_ZERO_MEMORY)
+          replacement_alloc = asan_calloc(1, dwBytes, &stack);
+        else
+          replacement_alloc = asan_malloc(dwBytes, &stack);
+        if (replacement_alloc) {
+          size_t old_size = heapSizeFunc(hHeap, dwFlags, lpMem);
+          if (old_size == ((SIZE_T)0) - 1) {
+            asan_free(replacement_alloc, &stack, FROM_MALLOC);
+            return nullptr;
+          }
+          REAL(memcpy)(replacement_alloc, lpMem, old_size);
+          freeFunc(hHeap, dwFlags, lpMem);
+        }
+        return replacement_alloc;
+      } else {
+        // owned by rtl or neither with unsupported ASAN flags,
+        // just pass back to original allocator
+        CHECK(ownershipState == RTL || ownershipState == NEITHER);
+        CHECK(!only_asan_supported_flags);
+        return reallocFunc(hHeap, dwFlags, lpMem, dwBytes);
+      }
+    }
+
+    if (ownershipState == ASAN && !only_asan_supported_flags) {
+      // Conversion to unsupported flags allocation,
+      // transfer this allocation back to the original allocator.
+      void *replacement_alloc = allocFunc(hHeap, dwFlags, dwBytes);
+      if (replacement_alloc) {
+        old_usable_size = asan_malloc_usable_size(lpMem, pc, bp);
+        REAL(memcpy)(replacement_alloc, lpMem, min(dwBytes, old_usable_size));
+        asan_free(lpMem, &stack, FROM_MALLOC);
+      }
+      return replacement_alloc;
+    }
+
+    CHECK((ownershipState == ASAN || ownershipState == NEITHER) &&
+          only_asan_supported_flags);
+    // At this point we should either be ASAN owned with ASAN supported flags
+    // or we owned by neither and have supported flags.
+    // Pass through even when it's neither since this could be a null realloc or
+    // UAF that ASAN needs to catch.
+  } else {
+    CHECK((HEAP_REALLOC_UNSUPPORTED_FLAGS & dwFlags) != 0 &&
+          "unsupported flags");
+  }
+  // asan_realloc will never reallocate in place, so for now this flag is
+  // unsupported until we figure out a way to fake this.
+  if (dwFlags & HEAP_REALLOC_IN_PLACE_ONLY)
+    return nullptr;
+
+  // HeapReAlloc and HeapAlloc both happily accept 0 sized allocations.
+  // passing a 0 size into asan_realloc will free the allocation.
+  // To avoid this and keep behavior consistent, fudge the size if 0.
+  // (asan_malloc already does this)
+  if (dwBytes == 0)
+    dwBytes = 1;
+
+  size_t old_size;
+  if (dwFlags & HEAP_ZERO_MEMORY)
+    old_size = asan_malloc_usable_size(lpMem, pc, bp);
+
+  void *ptr = asan_realloc(lpMem, dwBytes, &stack);
+  if (ptr == nullptr)
+    return nullptr;
+
+  if (dwFlags & HEAP_ZERO_MEMORY) {
+    size_t new_size = asan_malloc_usable_size(ptr, pc, bp);
+    if (old_size < new_size)
+      REAL(memset)(((u8 *)ptr) + old_size, 0, new_size - old_size);
+  }
+
+  return ptr;
+}
+}  // namespace __asan
+
+INTERCEPTOR_WINAPI(LPVOID, HeapReAlloc, HANDLE hHeap, DWORD dwFlags,
+                   LPVOID lpMem, SIZE_T dwBytes) {
+  return SharedReAlloc(REAL(HeapReAlloc), (SizeFunction)REAL(HeapSize),
+                       REAL(HeapFree), REAL(HeapAlloc), hHeap, dwFlags, lpMem,
+                       dwBytes);
+}
+
+// The following functions are undocumented and subject to change.
+// However, hooking them is necessary to hook Windows heap
+// allocations with detours and their definitions are unlikely to change.
+// Comments in /minkernel/ntos/rtl/heappublic.c indicate that these functions
+// are part of the heap's public interface.
+typedef ULONG LOGICAL;
+
+// This function is documented as part of the Driver Development Kit but *not*
+// the Windows Development Kit.
+NTSYSAPI LOGICAL RtlFreeHeap(PVOID HeapHandle, ULONG Flags,
+                             _Frees_ptr_opt_ PVOID BaseAddress);
+
+// This function is documented as part of the Driver Development Kit but *not*
+// the Windows Development Kit.
+NTSYSAPI PVOID RtlAllocateHeap(PVOID HeapHandle, ULONG Flags, SIZE_T Size);
+
+// This function is completely undocumented.
+PVOID
+RtlReAllocateHeap(PVOID HeapHandle, ULONG Flags, PVOID BaseAddress,
+                  SIZE_T Size);
+
+// This function is completely undocumented.
+SIZE_T
+RtlSizeHeap(PVOID HeapHandle, ULONG Flags, PVOID BaseAddress);
+
+INTERCEPTOR_WINAPI(SIZE_T, RtlSizeHeap, HANDLE HeapHandle, ULONG Flags,
+                   PVOID BaseAddress) {
+  if (!flags()->windows_hook_rtl_allocators ||
+      UNLIKELY(!asan_inited || OWNED_BY_RTL(HeapHandle, BaseAddress))) {
+    return REAL(RtlSizeHeap)(HeapHandle, Flags, BaseAddress);
+  }
+  GET_CURRENT_PC_BP_SP;
+  (void)sp;
+  return asan_malloc_usable_size(BaseAddress, pc, bp);
+}
+
+INTERCEPTOR_WINAPI(BOOL, RtlFreeHeap, HANDLE HeapHandle, ULONG Flags,
+                   PVOID BaseAddress) {
+  // Heap allocations happen before this function is hooked, so we must fall
+  // back to the original function if the pointer is not from the ASAN heap, or
+  // unsupported flags are provided.
+  if (!flags()->windows_hook_rtl_allocators ||
+      UNLIKELY((HEAP_FREE_UNSUPPORTED_FLAGS & Flags) != 0 ||
+               OWNED_BY_RTL(HeapHandle, BaseAddress))) {
+    return REAL(RtlFreeHeap)(HeapHandle, Flags, BaseAddress);
+  }
+  GET_STACK_TRACE_FREE;
+  asan_free(BaseAddress, &stack, FROM_MALLOC);
+  return true;
+}
+
+INTERCEPTOR_WINAPI(PVOID, RtlAllocateHeap, HANDLE HeapHandle, DWORD Flags,
+                   SIZE_T Size) {
+  // If the ASAN runtime is not initialized, or we encounter an unsupported
+  // flag, fall back to the original allocator.
+  if (!flags()->windows_hook_rtl_allocators ||
+      UNLIKELY(!asan_inited ||
+               (Flags & HEAP_ALLOCATE_UNSUPPORTED_FLAGS) != 0)) {
+    return REAL(RtlAllocateHeap)(HeapHandle, Flags, Size);
+  }
+  GET_STACK_TRACE_MALLOC;
+  void *p;
+  // Reading MSDN suggests that the *entire* usable allocation is zeroed out.
+  // Otherwise it is difficult to HeapReAlloc with HEAP_ZERO_MEMORY.
+  // https://blogs.msdn.microsoft.com/oldnewthing/20120316-00/?p=8083
+  if (Flags & HEAP_ZERO_MEMORY) {
+    p = asan_calloc(Size, 1, &stack);
+  } else {
+    p = asan_malloc(Size, &stack);
+  }
+  return p;
+}
+
+INTERCEPTOR_WINAPI(PVOID, RtlReAllocateHeap, HANDLE HeapHandle, ULONG Flags,
+                   PVOID BaseAddress, SIZE_T Size) {
+  // If it's actually a heap block which was allocated before the ASAN runtime
+  // came up, use the real RtlFreeHeap function.
+  if (!flags()->windows_hook_rtl_allocators)
+    return REAL(RtlReAllocateHeap)(HeapHandle, Flags, BaseAddress, Size);
+
+  return SharedReAlloc(REAL(RtlReAllocateHeap), REAL(RtlSizeHeap),
+                       REAL(RtlFreeHeap), REAL(RtlAllocateHeap), HeapHandle,
+                       Flags, BaseAddress, Size);
+}
+
+namespace __asan {
+
+static void TryToOverrideFunction(const char *fname, uptr new_func) {
+  // Failure here is not fatal. The CRT may not be present, and different CRT
+  // versions use different symbols.
+  if (!__interception::OverrideFunction(fname, new_func))
+    VPrintf(2, "Failed to override function %s\n", fname);
+}
+
+void ReplaceSystemMalloc() {
+#if defined(ASAN_DYNAMIC)
+  TryToOverrideFunction("free", (uptr)free);
+  TryToOverrideFunction("_free_base", (uptr)free);
+  TryToOverrideFunction("malloc", (uptr)malloc);
+  TryToOverrideFunction("_malloc_base", (uptr)malloc);
+  TryToOverrideFunction("_malloc_crt", (uptr)malloc);
+  TryToOverrideFunction("calloc", (uptr)calloc);
+  TryToOverrideFunction("_calloc_base", (uptr)calloc);
+  TryToOverrideFunction("_calloc_crt", (uptr)calloc);
+  TryToOverrideFunction("realloc", (uptr)realloc);
+  TryToOverrideFunction("_realloc_base", (uptr)realloc);
+  TryToOverrideFunction("_realloc_crt", (uptr)realloc);
+  TryToOverrideFunction("_recalloc", (uptr)_recalloc);
+  TryToOverrideFunction("_recalloc_base", (uptr)_recalloc);
+  TryToOverrideFunction("_recalloc_crt", (uptr)_recalloc);
+  TryToOverrideFunction("_msize", (uptr)_msize);
+  TryToOverrideFunction("_msize_base", (uptr)_msize);
+  TryToOverrideFunction("_expand", (uptr)_expand);
+  TryToOverrideFunction("_expand_base", (uptr)_expand);
+
+  if (flags()->windows_hook_rtl_allocators) {
+    INTERCEPT_FUNCTION(HeapSize);
+    INTERCEPT_FUNCTION(HeapFree);
+    INTERCEPT_FUNCTION(HeapReAlloc);
+    INTERCEPT_FUNCTION(HeapAlloc);
+
+    // Undocumented functions must be intercepted by name, not by symbol.
+    __interception::OverrideFunction("RtlSizeHeap", (uptr)WRAP(RtlSizeHeap),
+                                     (uptr *)&REAL(RtlSizeHeap));
+    __interception::OverrideFunction("RtlFreeHeap", (uptr)WRAP(RtlFreeHeap),
+                                     (uptr *)&REAL(RtlFreeHeap));
+    __interception::OverrideFunction("RtlReAllocateHeap",
+                                     (uptr)WRAP(RtlReAllocateHeap),
+                                     (uptr *)&REAL(RtlReAllocateHeap));
+    __interception::OverrideFunction("RtlAllocateHeap",
+                                     (uptr)WRAP(RtlAllocateHeap),
+                                     (uptr *)&REAL(RtlAllocateHeap));
+  } else {
+#define INTERCEPT_UCRT_FUNCTION(func)                                         \
+  if (!INTERCEPT_FUNCTION_DLLIMPORT("ucrtbase.dll",                           \
+                                    "api-ms-win-core-heap-l1-1-0.dll", func)) \
+    VPrintf(2, "Failed to intercept ucrtbase.dll import %s\n", #func);
+    INTERCEPT_UCRT_FUNCTION(HeapAlloc);
+    INTERCEPT_UCRT_FUNCTION(HeapFree);
+    INTERCEPT_UCRT_FUNCTION(HeapReAlloc);
+    INTERCEPT_UCRT_FUNCTION(HeapSize);
+#undef INTERCEPT_UCRT_FUNCTION
+  }
+  // Recent versions of ucrtbase.dll appear to be built with PGO and LTCG, which
+  // enable cross-module inlining. This means our _malloc_base hook won't catch
+  // all CRT allocations. This code here patches the import table of
+  // ucrtbase.dll so that all attempts to use the lower-level win32 heap
+  // allocation API will be directed to ASan's heap. We don't currently
+  // intercept all calls to HeapAlloc. If we did, we would have to check on
+  // HeapFree whether the pointer came from ASan of from the system.
+
+#endif  // defined(ASAN_DYNAMIC)
 }
 }  // namespace __asan
 
 #endif  // _WIN32

compiler-rt/lib/asan/asan_win.cc

 void InitializePlatformInterceptors() {
   // The interceptors were not designed to be removable, so we have to keep this
   // module alive for the life of the process.
   HMODULE pinned;
   CHECK(GetModuleHandleExW(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS |
                            GET_MODULE_HANDLE_EX_FLAG_PIN,
                            (LPCWSTR)&InitializePlatformInterceptors,
                            &pinned));
-
-  ASAN_INTERCEPT_FUNC(CreateThread);
-  ASAN_INTERCEPT_FUNC(SetUnhandledExceptionFilter);
-
-#ifdef _WIN64
-  ASAN_INTERCEPT_FUNC(__C_specific_handler);
-#else
-  ASAN_INTERCEPT_FUNC(_except_handler3);
-  ASAN_INTERCEPT_FUNC(_except_handler4);
-#endif
-
-  // Try to intercept kernel32!RaiseException, and if that fails, intercept
-  // ntdll!RtlRaiseException instead.
-  if (!::__interception::OverrideFunction("RaiseException",
-                                          (uptr)WRAP(RaiseException),
-                                          (uptr *)&REAL(RaiseException))) {
-    CHECK(::__interception::OverrideFunction("RtlRaiseException",
-                                             (uptr)WRAP(RtlRaiseException),
-                                             (uptr *)&REAL(RtlRaiseException)));
-  }
-}
-
-void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
-  UNIMPLEMENTED();
-}
-
-// ---------------------- TSD ---------------- {{{
-static bool tsd_key_inited = false;
-
-static __declspec(thread) void *fake_tsd = 0;
-
-void AsanTSDInit(void (*destructor)(void *tsd)) {
-  // FIXME: we're ignoring the destructor for now.
-  tsd_key_inited = true;
-}
-
-void *AsanTSDGet() {
-  CHECK(tsd_key_inited);
+
+  ASAN_INTERCEPT_FUNC(CreateThread);
+  ASAN_INTERCEPT_FUNC(SetUnhandledExceptionFilter);
+
+#ifdef _WIN64
+  ASAN_INTERCEPT_FUNC(__C_specific_handler);
+#else
+  ASAN_INTERCEPT_FUNC(_except_handler3);
+  ASAN_INTERCEPT_FUNC(_except_handler4);
+#endif
+
+  // Try to intercept kernel32!RaiseException, and if that fails, intercept
+  // ntdll!RtlRaiseException instead.
+  if (!::__interception::OverrideFunction("RaiseException",
+                                          (uptr)WRAP(RaiseException),
+                                          (uptr *)&REAL(RaiseException))) {
+    CHECK(::__interception::OverrideFunction("RtlRaiseException",
+                                             (uptr)WRAP(RtlRaiseException),
+                                             (uptr *)&REAL(RtlRaiseException)));
+  }
+}
+
+void AsanApplyToGlobals(globals_op_fptr op, const void *needle) {
+  UNIMPLEMENTED();
+}
+
+// ---------------------- TSD ---------------- {{{
+static bool tsd_key_inited = false;
+
+static __declspec(thread) void *fake_tsd = 0;
+
+
+// https://docs.microsoft.com/en-us/windows/desktop/api/winternl/ns-winternl-_teb
+// "[This structure may be altered in future versions of Windows. Applications
+// should use the alternate functions listed in this topic.]"
+typedef struct _TEB {
+  PVOID Reserved1[12];
+  // PVOID ThreadLocalStoragePointer; is here, at the last field in Reserved1.
+  PVOID ProcessEnvironmentBlock;
+  PVOID Reserved2[399];
+  BYTE Reserved3[1952];
+  PVOID TlsSlots[64];
+  BYTE Reserved4[8];
+  PVOID Reserved5[26];
+  PVOID ReservedForOle;
+  PVOID Reserved6[4];
+  PVOID TlsExpansionSlots;
+} TEB, *PTEB;
+
+constexpr int TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET = 11;
+BOOL IsTlsInitialized() {
+  PTEB teb = (PTEB)NtCurrentTeb();
+  return teb->Reserved1[TEB_RESERVED_FIELDS_THREAD_LOCAL_STORAGE_OFFSET] !=
+         nullptr;
+}
+
+
+void AsanTSDInit(void (*destructor)(void *tsd)) {
+  // FIXME: we're ignoring the destructor for now.
+  tsd_key_inited = true;
+}
+
+void *AsanTSDGet() {
+  CHECK(tsd_key_inited);
+if (flags()->windows_hook_rtl_allocators)
+  return IsTlsInitialized() ? fake_tsd : nullptr;
+else
   return fake_tsd;
 }
 
 void AsanTSDSet(void *tsd) {
   CHECK(tsd_key_inited);
   fake_tsd = tsd;
 }
 
 void PlatformTSDDtor(void *tsd) {
   AsanThread::TSDDtor(tsd);
 }
-// }}}
-
-// ---------------------- Various stuff ---------------- {{{
-void *AsanDoesNotSupportStaticLinkage() {
-#if defined(_DEBUG)
-#error Please build the runtime with a non-debug CRT: /MD or /MT
-#endif
-  return 0;
-}
-
-uptr FindDynamicShadowStart() {
-  uptr granularity = GetMmapGranularity();
-  uptr alignment = 8 * granularity;
-  uptr left_padding = granularity;
-  uptr space_size = kHighShadowEnd + left_padding;
-  uptr shadow_start = FindAvailableMemoryRange(space_size, alignment,
-                                               granularity, nullptr, nullptr);
-  CHECK_NE((uptr)0, shadow_start);
-  CHECK(IsAligned(shadow_start, alignment));
-  return shadow_start;
-}
-
-void AsanCheckDynamicRTPrereqs() {}
-
-void AsanCheckIncompatibleRT() {}
-
-void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
-  UNIMPLEMENTED();
-}
-
-void AsanOnDeadlySignal(int, void *siginfo, void *context) {
-  UNIMPLEMENTED();
-}
-
-#if SANITIZER_WINDOWS64
-// Exception handler for dealing with shadow memory.
-static LONG CALLBACK
-ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
-  uptr page_size = GetPageSizeCached();
-  // Only handle access violations.
-  if (exception_pointers->ExceptionRecord->ExceptionCode !=
-      EXCEPTION_ACCESS_VIOLATION) {
-    return EXCEPTION_CONTINUE_SEARCH;
-  }
-
-  // Only handle access violations that land within the shadow memory.
-  uptr addr =
-      (uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]);
-
-  // Check valid shadow range.
-  if (!AddrIsInShadow(addr)) return EXCEPTION_CONTINUE_SEARCH;
+// }}}
+
+// ---------------------- Various stuff ---------------- {{{
+void *AsanDoesNotSupportStaticLinkage() {
+#if defined(_DEBUG)
+#error Please build the runtime with a non-debug CRT: /MD or /MT
+#endif
+  return 0;
+}
+
+uptr FindDynamicShadowStart() {
+  uptr granularity = GetMmapGranularity();
+  uptr alignment = 8 * granularity;
+  uptr left_padding = granularity;
+  uptr space_size = kHighShadowEnd + left_padding;
+  uptr shadow_start = FindAvailableMemoryRange(space_size, alignment,
+                                               granularity, nullptr, nullptr);
+  CHECK_NE((uptr)0, shadow_start);
+  CHECK(IsAligned(shadow_start, alignment));
+  return shadow_start;
+}
+
+void AsanCheckDynamicRTPrereqs() {}
+
+void AsanCheckIncompatibleRT() {}
+
+void ReadContextStack(void *context, uptr *stack, uptr *ssize) {
+  UNIMPLEMENTED();
+}
+
+void AsanOnDeadlySignal(int, void *siginfo, void *context) {
+  UNIMPLEMENTED();
+}
+
+#if SANITIZER_WINDOWS64
+// Exception handler for dealing with shadow memory.
+static LONG CALLBACK
+ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
+  uptr page_size = GetPageSizeCached();
+  // Only handle access violations.
+  if (exception_pointers->ExceptionRecord->ExceptionCode !=
+          EXCEPTION_ACCESS_VIOLATION ||
+      exception_pointers->ExceptionRecord->NumberParameters < 2) {
+    __asan_handle_no_return();
+    return EXCEPTION_CONTINUE_SEARCH;
+  }
+
+  // Only handle access violations that land within the shadow memory.
+  uptr addr =
+      (uptr)(exception_pointers->ExceptionRecord->ExceptionInformation[1]);
+
+  // Check valid shadow range.
+  if (!AddrIsInShadow(addr)){
+    __asan_handle_no_return();
+    return EXCEPTION_CONTINUE_SEARCH;
+  }
 
   // This is an access violation while trying to read from the shadow. Commit
   // the relevant page and let execution continue.
 
   // Determine the address of the page that is being accessed.
   uptr page = RoundDownTo(addr, page_size);
 
   // Commit the page.

compiler-rt/test/asan/TestCases/Windows/dll_host.cc

 // IMPORT: __asan_wrap_HeapAlloc
 // IMPORT: __asan_wrap_HeapFree
 // IMPORT: __asan_wrap_HeapReAlloc
 // IMPORT: __asan_wrap_HeapSize
 // IMPORT: __asan_wrap_CreateThread
 // IMPORT: __asan_wrap_RaiseException
 // IMPORT: __asan_wrap_RtlRaiseException
 // IMPORT: __asan_wrap_SetUnhandledExceptionFilter
+// IMPORT: __asan_wrap_RtlSizeHeap
+// IMPORT: __asan_wrap_RtlAllocateHeap
+// IMPORT: __asan_wrap_RtlReAllocateHeap
+// IMPORT: __asan_wrap_RtlFreeHeap
 //
 // RUN: cat %t.imports1 %t.imports2 | sort | uniq > %t.imports-sorted
 // RUN: cat %t.exports1 %t.exports2 | sort | uniq > %t.exports-sorted
 //
 // Now make sure the DLL thunk imports everything:
 // RUN: echo
 // RUN: echo "=== NOTE === If you see a mismatch below, please update asan_win_dll_thunk.cc"
 // RUN: diff %t.imports-sorted %t.exports-sorted

compiler-rt/test/asan/TestCases/Windows/dll_unload.cc

+#include <windows.h>
+#include <stdio.h>
+
+// RUN: %clang_cl_asan -LD /Od -DDLL %s -Fe%t.dll
+// RUN: %clang_cl /Od -DEXE %s -Fe%te.exe
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %te.exe %t.dll 2>&1 | FileCheck %s
+// REQUIRES: asan-dynamic-runtime
+// REQUIRES: asan-32-bits
+
+#include <windows.h>
+#include <stdio.h>
+#include <cassert>
+extern "C" {
+#if defined(EXE)
+
+int main(int argc, char **argv) {
+    void* region_without_hooks = HeapAlloc(GetProcessHeap(), 0, 10);
+    HMODULE lib = LoadLibraryA(argv[1]);
+    assert(lib != INVALID_HANDLE_VALUE);
+
+    void* region_w_hooks = HeapAlloc(GetProcessHeap(), 0, 10);
+    assert(region_w_hooks != nullptr);
+    assert(0 != FreeLibrary(lib));
+
+    fprintf(stderr, "WITHOUT:0x%08x\n", (unsigned int)region_without_hooks);
+    fprintf(stderr, "WITH:0x%08x\n", (unsigned int)region_w_hooks);
+
+    assert(0 != HeapFree(GetProcessHeap(), 0, region_without_hooks));
+    assert(0 != HeapFree(GetProcessHeap(), 0, region_w_hooks));
+
+    HeapFree(GetProcessHeap(), 0, region_w_hooks); //will dump
+
+}
+#elif defined(DLL)
+// This global is registered at startup.
+
+BOOL WINAPI DllMain(HMODULE, DWORD reason, LPVOID) {
+  fprintf(stderr, "in DLL(reason=%d)\n", (int)reason);
+  fflush(0);
+  return TRUE;
+}
+
+// CHECK: in DLL(reason=1)
+// CHECK: in DLL(reason=0)
+// CHECK: WITHOUT:[[WITHOUT:0x[0-9a-fA-F]+]]
+// CHECK: WITH:[[WITH:0x[0-9a-fA-F]+]]
+// CHECK: AddressSanitizer: attempting double-free on [[WITH]] in thread T0:
+
+#else
+# error oops!
+#endif
+}

compiler-rt/test/asan/TestCases/Windows/heapalloc.cc

+// XFAIL: asan-64-bits
+// RUN: %clang_cl_asan -O0 %s -Fe%t
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %t 2>&1 | FileCheck %s
+
+#include <windows.h>
+
+int main() {
+  char *buffer;
+  buffer = (char*)HeapAlloc(GetProcessHeap(), 0, 32),
+  buffer[33] = 'a';
+// CHECK: AddressSanitizer: heap-buffer-overflow on address [[ADDR:0x[0-9a-f]+]]
+// CHECK: WRITE of size 1 at [[ADDR]] thread T0
+}

compiler-rt/test/asan/TestCases/Windows/heapalloc_dll_double_free.cc

+#include <windows.h>
+#include <stdio.h>
+
+// RUN: %clang_cl_asan -LD /Od -DDLL %s -Fe%t.dll
+// RUN: %clang_cl /Od -DEXE %s -Fe%te.exe
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %te.exe %t.dll 2>&1 | FileCheck %s
+// REQUIRES: asan-dynamic-runtime
+// REQUIRES: asan-32-bits
+
+#include <windows.h>
+#include <stdio.h>
+#include <cassert>
+extern "C" {
+#if defined(EXE)
+
+int main(int argc, char **argv) {
+    void* region_without_hooks = HeapAlloc(GetProcessHeap(), 0, 10);
+    HMODULE lib = LoadLibraryA(argv[1]);
+    assert(lib != INVALID_HANDLE_VALUE);
+    assert(0 != FreeLibrary(lib));
+    assert(0 != HeapFree(GetProcessHeap(), 0, region_without_hooks));
+    assert(0 != HeapFree(GetProcessHeap(), 0, region_without_hooks));
+}
+#elif defined(DLL)
+// This global is registered at startup.
+
+BOOL WINAPI DllMain(HMODULE, DWORD reason, LPVOID) {
+  fprintf(stderr, "in DLL(reason=%d)\n", (int)reason);
+  fflush(0);
+  return TRUE;
+}
+
+// CHECK: in DLL(reason=1)
+// CHECK: in DLL(reason=0)
+// CHECK: AddressSanitizer: nested bug in the same thread, aborting.
+
+#else
+# error oops!
+#endif
+}

compiler-rt/test/asan/TestCases/Windows/heapalloc_dll_unload_realloc_uaf.cc

+#include <windows.h>
+#include <stdio.h>
+
+// RUN: %clang_cl_asan -LD /Od -DDLL %s -Fe%t.dll
+// RUN: %clang_cl /Od -DEXE %s -Fe%te.exe
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %te.exe %t.dll 2>&1 | FileCheck %s
+// REQUIRES: asan-dynamic-runtime
+// REQUIRES: asan-32-bits
+
+#include <windows.h>
+#include <stdio.h>
+#include <cassert>
+extern "C" {
+#if defined(EXE)
+
+int main(int argc, char **argv) {
+    void* region_without_hooks = HeapAlloc(GetProcessHeap(), 0, 10);
+    HMODULE lib = LoadLibraryA(argv[1]);
+    assert(lib != INVALID_HANDLE_VALUE);
+    assert(0 != FreeLibrary(lib));
+    assert(0 != HeapFree(GetProcessHeap(), 0, region_without_hooks));
+    HeapReAlloc(GetProcessHeap(), 0, region_without_hooks, 100); //should throw nested error
+}
+#elif defined(DLL)
+// This global is registered at startup.
+
+BOOL WINAPI DllMain(HMODULE, DWORD reason, LPVOID) {
+  fprintf(stderr, "in DLL(reason=%d)\n", (int)reason);
+  fflush(0);
+  return TRUE;
+}
+
+// CHECK: in DLL(reason=1)
+// CHECK: in DLL(reason=0)
+// CHECK: AddressSanitizer: nested bug in the same thread, aborting.
+
+#else
+# error oops!
+#endif
+}

compiler-rt/test/asan/TestCases/Windows/heapalloc_doublefree.cc

+// RUN: %clang_cl_asan -O0 %s -Fe%t
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+#include <windows.h>
+#include <cassert>
+
+int main(){
+    void* allocation = HeapAlloc(GetProcessHeap(),0,10);
+    assert(allocation != 0);
+    assert( HeapFree(GetProcessHeap(),0, allocation) );
+    HeapFree(GetProcessHeap(),0, allocation); //will dump
+    assert(0 && "HeapFree double free should produce an ASAN dump\n" );
+    return 0;
+}
+
+// CHECK: AddressSanitizer: attempting double-free on [[addr:0x[0-9a-fA-F]+]] in thread T0:
 No newline at end of file

compiler-rt/test/asan/TestCases/Windows/heapalloc_flags_fallback.cc

+// RUN: %clang_cl_asan -O0 %s -Fe%t
+// RUN: %run %t 2>&1 | FileCheck %s
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+#include <assert.h>
+#include <stdio.h>
+#include <windows.h>
+
+    extern "C" int
+    __sanitizer_get_ownership(const volatile void *p);
+
+int main() {
+  char *buffer;
+  buffer = (char*)HeapAlloc(GetProcessHeap(), HEAP_GENERATE_EXCEPTIONS, 32);
+  buffer[0] = 'a';
+  assert(!__sanitizer_get_ownership(buffer));
+  HeapFree(GetProcessHeap(), 0, buffer);
+  puts("Okay");
+// CHECK: Okay
+}

compiler-rt/test/asan/TestCases/Windows/heapalloc_huge.cc

+// RUN: %clang_cl_asan -O0 %s -Fe%t
+// RUN: %env_asan_opts=allocator_may_return_null=true %run %t
+// RUN: %env_asan_opts=allocator_may_return_null=true:windows_hook_rtl_allocators=true %run %t
+// XFAIL: asan-64-bits
+#include <windows.h>
+int main(){
+    void* nope = HeapAlloc(GetProcessHeap(),0,((size_t)0)-1);
+    return (nope == nullptr) ? 0 : 1;
+}
 No newline at end of file

compiler-rt/test/asan/TestCases/Windows/heapalloc_rtl_transfer.cc

+#include <windows.h>
+#include <cassert>
+#include <stdio.h>
+#include "sanitizer\allocator_interface.h"
+
+// RUN: %clang_cl_asan %s -o%t
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+
+using AllocateFunctionPtr = PVOID (__stdcall*)(PVOID, ULONG, SIZE_T);
+using ReAllocateFunctionPtr = PVOID (__stdcall*)(PVOID, ULONG, PVOID, SIZE_T);
+
+using FreeFunctionPtr = PVOID (__stdcall*)(PVOID, ULONG, PVOID);
+
+int main() {
+  HMODULE NtDllHandle = GetModuleHandle("ntdll.dll");
+  if (!NtDllHandle) {
+    puts("Couldn't load ntdll??");
+    return -1;
+  }
+
+  auto RtlAllocateHeap_ptr = (AllocateFunctionPtr)GetProcAddress(NtDllHandle, "RtlAllocateHeap");
+  if (RtlAllocateHeap_ptr == 0) {
+    puts("Couldn't find RtlAllocateHeap");
+    return -1;
+  }
+
+  auto RtlReAllocateHeap_ptr = (ReAllocateFunctionPtr)GetProcAddress(NtDllHandle, "RtlReAllocateHeap");
+  if (RtlReAllocateHeap_ptr == 0) {
+    puts("Couldn't find RtlReAllocateHeap");
+    return -1;
+  }
+
+
+    //owned by rtl
+    void* alloc =  RtlAllocateHeap_ptr(GetProcessHeap(), \
+                    HEAP_GENERATE_EXCEPTIONS|HEAP_ZERO_MEMORY, 100);
+    assert(alloc);
+    for (int i = 0; i < 100; i++){
+        assert(((char*)alloc)[i] == 0);
+        ((char*)alloc)[i] = '\xcc';
+    }
+
+    // still owned by rtl
+    alloc =  RtlReAllocateHeap_ptr(GetProcessHeap(), \
+                HEAP_GENERATE_EXCEPTIONS | HEAP_ZERO_MEMORY , alloc, 500);
+    assert(alloc && !__sanitizer_get_ownership(alloc) && HeapValidate(GetProcessHeap(),0,alloc));
+    for (int i = 0; i < 100; i++){
+        assert(((char*)alloc)[i] == '\xcc');
+    }
+    for (int i = 100; i < 500; i++){
+        assert(((char*)alloc)[i] == 0);
+        ((char*)alloc)[i] = '\xcc';
+    }
+
+    //convert to asan owned
+    void* realloc = RtlReAllocateHeap_ptr(GetProcessHeap(), \
+                        HEAP_ZERO_MEMORY, alloc, 600);
+    alloc = nullptr;
+    assert(realloc && __sanitizer_get_ownership(realloc));
+
+    for (int i = 0; i < 500; i++){
+        assert(((char*)realloc)[i] == '\xcc');
+    }
+    for (int i = 500; i < 600; i++){
+        assert(((char*)realloc)[i] == 0);
+        ((char*)realloc)[i] = '\xcc';
+    }
+    realloc = RtlReAllocateHeap_ptr(GetProcessHeap(), \
+                        HEAP_ZERO_MEMORY, realloc, 2048);
+    assert(realloc && __sanitizer_get_ownership(realloc));
+
+    for (int i = 0; i < 600; i++){
+        assert(((char*)realloc)[i] == '\xcc');
+    }
+    for (int i = 600; i < 2048; i++){
+        assert(((char*)realloc)[i] == 0);
+        ((char*)realloc)[i] = '\xcc';
+    }
+    //convert back to rtl owned;
+    alloc = RtlReAllocateHeap_ptr(GetProcessHeap(), \
+                HEAP_ZERO_MEMORY|HEAP_GENERATE_EXCEPTIONS, realloc, 100);
+    assert(alloc && !__sanitizer_get_ownership(alloc) && HeapValidate(GetProcessHeap(),0,alloc));
+    for (int i = 0; i < 100; i++){
+        assert(((char*)alloc)[i] == '\xcc');
+        ((char*)alloc)[i] = 0;
+    }
+
+    auto usable_size = HeapSize(GetProcessHeap(), 0, alloc);
+    for (int i = 100; i < usable_size; i++){
+        assert(((char*)alloc)[i] == 0);
+    }
+
+    printf("Success\n");
+}
+
+// CHECK-NOT: Assertion failed:
+// CHECK-NOT: AddressSanitizer
+// CHECK: Success
 No newline at end of file

compiler-rt/test/asan/TestCases/Windows/heapalloc_sanity.cc

+// RUN: %clang_cl_asan -O0 %s -Fe%t
+// RUN: %run %t 2>&1 | FileCheck %s
+#include <stdio.h>
+#include <windows.h>
+
+int main() {
+  char *buffer;
+  buffer = (char*)HeapAlloc(GetProcessHeap(), 0, 32),
+  buffer[0] = 'a';
+  HeapFree(GetProcessHeap(), 0, buffer);
+  puts("Okay");
+// CHECK: Okay
+}

compiler-rt/test/asan/TestCases/Windows/heapalloc_transfer.cc

+#include <windows.h>
+#include <cassert>
+#include <stdio.h>
+#include "sanitizer\allocator_interface.h"
+// RUN: %clang_cl_asan %s -o%t
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+
+int main(){
+    //owned by rtl
+    void* alloc =  HeapAlloc(GetProcessHeap(), HEAP_GENERATE_EXCEPTIONS, 100);
+    assert(alloc);
+    // still owned by rtl
+    alloc =  HeapReAlloc(GetProcessHeap(), HEAP_GENERATE_EXCEPTIONS, alloc, 100);
+    assert(alloc && !__sanitizer_get_ownership(alloc) && HeapValidate(GetProcessHeap(),0,alloc));
+    //convert to asan owned
+    void* realloc = HeapReAlloc(GetProcessHeap(), 0, alloc, 500);
+    alloc = nullptr;
+    assert(realloc && __sanitizer_get_ownership(realloc));
+    //convert back to rtl owned;
+    alloc = HeapReAlloc(GetProcessHeap(), HEAP_GENERATE_EXCEPTIONS, realloc, 100);
+    assert(alloc && !__sanitizer_get_ownership(alloc) && HeapValidate(GetProcessHeap(),0,alloc));
+    printf("Success\n");
+}
+
+// CHECK-NOT: assert
+// CHECK-NOT: AddressSanitizer
+// CHECK: Success
 No newline at end of file

compiler-rt/test/asan/TestCases/Windows/heapalloc_uaf.cc

+// RUN: %clang_cl_asan -O0 %s -Fe%t
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+#include <windows.h>
+
+int main() {
+  char *buffer;
+  buffer = (char*)HeapAlloc(GetProcessHeap(), 0, 32),
+  HeapFree(GetProcessHeap(), 0, buffer);
+  buffer[0] = 'a';
+// CHECK: AddressSanitizer: heap-use-after-free on address [[ADDR:0x[0-9a-f]+]]
+// CHECK: WRITE of size 1 at [[ADDR]] thread T0
+}

compiler-rt/test/asan/TestCases/Windows/heapalloc_zero_size.cc

+// RUN: %clang_cl_asan /Od -o %t %s
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true %run %t 2>&1 | FileCheck %s
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=false %run %t 2>&1 | FileCheck %s
+// RUN: %clang_cl /Od -o %t %s
+// RUN: %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+#include <cassert>
+#include <stdio.h>
+#include <windows.h>
+
+int main() {
+  HANDLE heap = HeapCreate(0, 0, 0);
+  void *ptr = HeapAlloc(heap, 0, 4);
+  assert(ptr);
+  void *ptr2 = HeapReAlloc(heap, 0, ptr, 0);
+  assert(ptr2);
+  HeapFree(heap, 0, ptr2);
+  fprintf(stderr, "passed!\n");
+}
+
+// CHECK-NOT: double-free
+// CHECK-NOT: AddressSanitizer
+// CHECK: passed!

compiler-rt/test/asan/TestCases/Windows/heaprealloc.cc

+// RUN: %clang_cl_asan -O0 %s -Fe%t
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+#include <stdio.h>
+#include <windows.h>
+
+int main() {
+  char *oldbuf;
+  size_t sz = 8;
+  HANDLE procHeap = GetProcessHeap();
+  oldbuf = (char*)HeapAlloc(procHeap, 0, sz);
+  char *newbuf = oldbuf;
+  while (oldbuf == newbuf) {
+    sz *= 2;
+    newbuf = (char *)HeapReAlloc(procHeap, 0, oldbuf, sz);
+  }
+
+  newbuf[0] = 'a';
+  oldbuf[0] = 'a';
+// CHECK: AddressSanitizer: heap-use-after-free on address [[ADDR:0x[0-9a-f]+]]
+// CHECK: WRITE of size 1 at [[WRITE2:0x[0-9a-f]+]] thread T0
+// CHECK: #0 {{0x[0-9a-f]+ in main.*}}:[[@LINE-3]]
+}

compiler-rt/test/asan/TestCases/Windows/heaprealloc_alloc_zero.cc

+// RUN: %clang_cl_asan /Od /MT -o %t %s
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+#include <windows.h>
+#include <cassert>
+#include <iostream>
+
+
+int main(){
+    void* ptr = malloc(0);
+    if (ptr)
+        std::cerr << "allocated!\n";
+    ((char*)ptr)[0] = '\xff'; //check this 'allocate 1 instead of 0' hack hasn't changed
+
+    free(ptr);
+
+    /*
+        HeapAlloc hack for our asan interceptor is to change 0
+        sized allocations to size 1 to avoid weird inconsistencies
+        between how realloc and heaprealloc handle 0 size allocations.
+
+        Note this test relies on these instructions being intercepted.
+        Without ASAN HeapRealloc on line 27 would return a ptr whose
+        HeapSize would be 0. This test makes sure that the underlying behavior
+        of our hack hasn't changed underneath us.
+
+        We can get rid of the test (or change it to test for the correct
+        behavior) once we fix the interceptor or write a different allocator
+        to handle 0 sized allocations properly by default.
+
+    */
+    ptr = HeapAlloc(GetProcessHeap(),0,0);
+    if (!ptr) return 1;
+    void* ptr2 = HeapReAlloc(GetProcessHeap(),0,ptr,0);
+    if (!ptr2) return 1;
+    size_t heapsize =  HeapSize(GetProcessHeap(),0,ptr2);
+    if ( heapsize != 1 ){ // will be 0 without ASAN turned on
+        std::cerr << "HeapAlloc size failure! " << heapsize << " != 1\n";
+        return 1;
+    }
+    void* ptr3 = HeapReAlloc(GetProcessHeap(),0,ptr2,3);
+    if (!ptr3) return 1;
+    heapsize = HeapSize(GetProcessHeap(),0,ptr3);
+
+    if ( heapsize != 3 ){
+        std::cerr << "HeapAlloc size failure! " << heapsize << " != 3\n";
+        return 1;
+    }
+    HeapFree(GetProcessHeap(),0,ptr3);
+    return 0;
+}
+
+// CHECK: allocated!
+// CHECK-NOT: heap-buffer-overflow
+// CHECK-NOT: AddressSanitizer
+// CHECK-NOT: HeapAlloc size failure!
 No newline at end of file

compiler-rt/test/asan/TestCases/Windows/heaprealloc_zero_size.cc

 // RUN: %clang_cl_asan /Od -o %t %s
-// RUN: %run %t 2>&1 | FileCheck %s
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true %run %t 2>&1 | FileCheck %s
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=false %run %t 2>&1 | FileCheck %s
 // RUN: %clang_cl /Od -o %t %s
 // RUN: %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
 #include <cassert>
 #include <stdio.h>
 #include<windows.h>
 
 int main() {
   HANDLE heap = HeapCreate(0, 0, 0);
   void *ptr = HeapAlloc(heap, 0, 4);
   assert(ptr);
   void *ptr2 = HeapReAlloc(heap, 0, ptr, 0);
   assert(ptr2);
   HeapFree(heap, 0, ptr2);
   fprintf(stderr, "passed!\n");
 }
 
 // CHECK-NOT: double-free
 // CHECK-NOT: AddressSanitizer
 No newline at end of file
 

compiler-rt/test/asan/TestCases/Windows/queue_user_work_item_report.cc

 // RUN: %clang_cl_asan -O0 %s -Fe%t
 // RUN: not %run %t 2>&1 | FileCheck %s
 
 #include <windows.h>
 
 HANDLE done;
 
 DWORD CALLBACK work_item(LPVOID) {
   int subscript = -1;
-  volatile char stack_buffer[42];
+  volatile char stack_buffer[42];
   stack_buffer[subscript] = 42;
 // CHECK: AddressSanitizer: stack-buffer-underflow on address [[ADDR:0x[0-9a-f]+]]
-// CHECK: WRITE of size 1 at [[ADDR]] thread T1
+// CHECK: WRITE of size 1 at [[ADDR]] thread T{{[0-9]+}}
 // CHECK:   {{#0 .* work_item.*queue_user_work_item_report.cc}}:[[@LINE-3]]
   SetEvent(done);
   return 0;
 }
 
 int main(int argc, char **argv) {
   done = CreateEvent(0, false, false, "job is done");
   if (!done)
     return 1;
 // CHECK-NOT: Thread T1 created
   QueueUserWorkItem(&work_item, nullptr, 0);
   if (WAIT_OBJECT_0 != WaitForSingleObject(done, 10 * 1000))
     return 2;
 }

compiler-rt/test/asan/TestCases/Windows/rtlallocateheap.cc

+// RUN: %clang_cl_asan -O0 %s -Fe%t /MD
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+// REQUIRES: asan-rtl-heap-interception
+
+#include <stdio.h>
+#include <windows.h>
+
+using AllocateFunctionPtr = PVOID (__stdcall*)(PVOID, ULONG, SIZE_T);
+using FreeFunctionPtr = PVOID (__stdcall*)(PVOID, ULONG, PVOID);
+
+int main() {
+  HMODULE NtDllHandle = GetModuleHandle("ntdll.dll");
+  if (!NtDllHandle) {
+    puts("Couldn't load ntdll??");
+    return -1;
+  }
+
+  auto RtlAllocateHeap_ptr = (AllocateFunctionPtr)GetProcAddress(NtDllHandle, "RtlAllocateHeap");
+  if (RtlAllocateHeap_ptr == 0) {
+    puts("Couldn't RtlAllocateHeap");
+    return -1;
+  }
+
+  char *buffer;
+  buffer = (char*)RtlAllocateHeap_ptr(GetProcessHeap(), 0, 32),
+  buffer[33] = 'a';
+// CHECK: AddressSanitizer: heap-buffer-overflow on address [[ADDR:0x[0-9a-f]+]]
+// CHECK: WRITE of size 1 at [[ADDR]] thread T0
+}

compiler-rt/test/asan/TestCases/Windows/rtlallocateheap_dll_unload_double_free.cc

+// RUN: %clang_cl_asan -LD /Od -DDLL %s -Fe%t.dll
+// RUN: %clang_cl /Od -DEXE %s -Fe%te.exe
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %te.exe %t.dll 2>&1 | FileCheck %s
+// REQUIRES: asan-dynamic-runtime
+// REQUIRES: asan-32-bits
+// REQUIRES: asan-rtl-heap-interception
+
+#include <cassert>
+#include <stdio.h>
+#include <windows.h>
+
+extern "C" {
+#if defined(EXE)
+using AllocateFunctionPtr = PVOID(__stdcall *)(PVOID, ULONG, SIZE_T);
+using FreeFunctionPtr = PVOID(__stdcall *)(PVOID, ULONG, PVOID);
+
+int main(int argc, char **argv) {
+  HMODULE NtDllHandle = GetModuleHandle("ntdll.dll");
+  if (!NtDllHandle) {
+    puts("Couldn't load ntdll??");
+    return -1;
+  }
+
+  auto RtlAllocateHeap_ptr =
+      (AllocateFunctionPtr)GetProcAddress(NtDllHandle, "RtlAllocateHeap");
+  if (RtlAllocateHeap_ptr == 0) {
+    puts("Couldn't RtlAllocateHeap");
+    return -1;
+  }
+
+  auto RtlFreeHeap_ptr =
+      (FreeFunctionPtr)GetProcAddress(NtDllHandle, "RtlFreeHeap");
+  if (RtlFreeHeap_ptr == 0) {
+    puts("Couldn't get RtlFreeHeap");
+    return -1;
+  }
+
+  char *buffer;
+  buffer = (char *)RtlAllocateHeap_ptr(GetProcessHeap(), 0, 32);
+
+  HMODULE lib = LoadLibraryA(argv[1]);
+  assert(lib != INVALID_HANDLE_VALUE);
+  assert(0 != FreeLibrary(lib));
+
+  if (!RtlFreeHeap_ptr(GetProcessHeap(), 0, buffer)) {
+    puts("Couldn't RtlFreeHeap");
+    return -1;
+  }
+  // Because this pointer was allocated pre-hooking,
+  // this will dump as a nested bug. Asan attempts to free
+  // the pointer and AV's, so the ASAN exception handler
+  // will dump as a 'nested bug'.
+  RtlFreeHeap_ptr(GetProcessHeap(), 0, buffer);
+}
+
+#elif defined(DLL)
+// This global is registered at startup.
+
+BOOL WINAPI DllMain(HMODULE, DWORD reason, LPVOID) {
+  fprintf(stderr, "in DLL(reason=%d)\n", (int)reason);
+  fflush(0);
+  return TRUE;
+}
+
+// CHECK: in DLL(reason=1)
+// CHECK: in DLL(reason=0)
+// CHECK: AddressSanitizer: nested bug in the same thread, aborting.
+
+#else
+#error oops!
+#endif
+}

compiler-rt/test/asan/TestCases/Windows/rtlallocateheap_dll_unload_realloc.cc

+// RUN: %clang_cl_asan -LD /Od -DDLL %s -Fe%t.dll
+// RUN: %clang_cl /Od -DEXE %s -Fe%te.exe
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %te.exe %t.dll 2>&1 | FileCheck %s
+// REQUIRES: asan-dynamic-runtime
+// REQUIRES: asan-32-bits
+// REQUIRES: asan-rtl-heap-interception
+
+#include <cassert>
+#include <stdio.h>
+#include <windows.h>
+
+extern "C" {
+#if defined(EXE)
+using AllocateFunctionPtr = PVOID(__stdcall *)(PVOID, ULONG, SIZE_T);
+using FreeFunctionPtr = PVOID(__stdcall *)(PVOID, ULONG, PVOID);
+using RtlReAllocateHeapPtr = PVOID(__stdcall *)(PVOID, ULONG, PVOID, SIZE_T);
+
+int main(int argc, char **argv) {
+  HMODULE NtDllHandle = GetModuleHandle("ntdll.dll");
+  if (!NtDllHandle) {
+    puts("Couldn't load ntdll??");
+    return -1;
+  }
+
+  auto RtlAllocateHeap_ptr =
+      (AllocateFunctionPtr)GetProcAddress(NtDllHandle, "RtlAllocateHeap");
+  if (RtlAllocateHeap_ptr == 0) {
+    puts("Couldn't RtlAllocateHeap");
+    return -1;
+  }
+
+  auto RtlFreeHeap_ptr =
+      (FreeFunctionPtr)GetProcAddress(NtDllHandle, "RtlFreeHeap");
+  if (RtlFreeHeap_ptr == 0) {
+    puts("Couldn't get RtlFreeHeap");
+    return -1;
+  }
+
+  auto RtlReAllocateHeap_ptr =
+      (RtlReAllocateHeapPtr)GetProcAddress(NtDllHandle, "RtlReAllocateHeap");
+  if (RtlReAllocateHeap_ptr == 0) {
+    puts("Couldn't get rtlreallocateheap\n");
+    return -1;
+  }
+
+  char *buffer;
+  buffer = (char *)RtlAllocateHeap_ptr(GetProcessHeap(), 0, 32);
+
+  HMODULE lib = LoadLibraryA(argv[1]);
+  assert(lib != INVALID_HANDLE_VALUE);
+  assert(0 != FreeLibrary(lib));
+
+  if (!RtlFreeHeap_ptr(GetProcessHeap(), 0, buffer)) {
+    puts("Couldn't RtlFreeHeap");
+    return -1;
+  }
+  RtlReAllocateHeap_ptr(GetProcessHeap(), 0, buffer, 100); // should dump
+}
+
+#elif defined(DLL)
+// This global is registered at startup.
+
+BOOL WINAPI DllMain(HMODULE, DWORD reason, LPVOID) {
+  fprintf(stderr, "in DLL(reason=%d)\n", (int)reason);
+  fflush(0);
+  return TRUE;
+}
+
+// CHECK: in DLL(reason=1)
+// CHECK: in DLL(reason=0)
+// CHECK: AddressSanitizer: nested bug in the same thread, aborting.
+
+#else
+#error oops!
+#endif
+}

compiler-rt/test/asan/TestCases/Windows/rtlallocateheap_flags_fallback.cc

+// RUN: %clang_cl_asan -O0 %s -Fe%t /MD
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+// REQUIRES: asan-rtl-heap-interception
+
+#include <assert.h>
+#include <stdio.h>
+#include <windows.h>
+
+extern "C" int __sanitizer_get_ownership(const volatile void *p);
+using AllocateFunctionPtr = PVOID (__stdcall*)(PVOID, ULONG, SIZE_T);
+using FreeFunctionPtr = PVOID (__stdcall*)(PVOID, ULONG, PVOID);
+
+int main() {
+  HMODULE NtDllHandle = GetModuleHandle("ntdll.dll");
+  if (!NtDllHandle) {
+    puts("Couldn't load ntdll??");
+    return -1;
+  }
+
+  auto RtlAllocateHeap_ptr = (AllocateFunctionPtr)GetProcAddress(NtDllHandle, "RtlAllocateHeap");
+  if (RtlAllocateHeap_ptr == 0) {
+    puts("Couldn't RtlAllocateHeap");
+    return -1;
+  }
+
+  auto RtlFreeHeap_ptr = (FreeFunctionPtr)GetProcAddress(NtDllHandle, "RtlFreeHeap");
+  if (RtlFreeHeap_ptr == 0) {
+    puts("Couldn't RtlFreeHeap");
+    return -1;
+  }
+
+  char *winbuf;
+  char *asanbuf;
+  winbuf = (char*)RtlAllocateHeap_ptr(GetProcessHeap(), HEAP_GENERATE_EXCEPTIONS, 32),
+  asanbuf = (char*)RtlAllocateHeap_ptr(GetProcessHeap(), 0, 32),
+  winbuf[0] = 'a';
+  assert(!__sanitizer_get_ownership(winbuf));
+  assert(__sanitizer_get_ownership(asanbuf));
+
+  RtlFreeHeap_ptr(GetProcessHeap(), 0, winbuf);
+  RtlFreeHeap_ptr(GetProcessHeap(), 0, asanbuf);
+  puts("Okay");
+// CHECK: Okay
+}

compiler-rt/test/asan/TestCases/Windows/rtlallocateheap_zero.cc

+// RUN: %clang_cl_asan -O0 %s -Fe%t /MD
+// RUN: %env_asan_opts=windows_hook_rtl_allocators=true not %run %t 2>&1 | FileCheck %s
+// XFAIL: asan-64-bits
+// REQUIRES: asan-rtl-heap-interception
+
+#include <assert.h>
+#include <stdio.h>
+#include <windows.h>
+
+using AllocateFunctionPtr = PVOID (__stdcall*)(PVOID, ULONG, SIZE_T);
+using ReAllocateFunctionPtr = PVOID (__stdcall*)(PVOID, ULONG, PVOID, SIZE_T);
+using FreeFunctionPtr = PVOID (__stdcall*)(PVOID, ULONG, PVOID);
+
+int main() {
+  HMODULE NtDllHandle = GetModuleHandle("ntdll.dll");
+  if (!NtDllHandle) {
+    puts("Couldn't load ntdll??");
+    return -1;
+  }
+
+  auto RtlAllocateHeap_ptr = (AllocateFunctionPtr)GetProcAddress(NtDllHandle, "RtlAllocateHeap");
+  if (RtlAllocateHeap_ptr == 0) {
+    puts("Couldn't find RtlAllocateHeap");
+    return -1;
+  }
+
+  auto RtlReAllocateHeap_ptr = (ReAllocateFunctionPtr)GetProcAddress(NtDllHandle, "RtlReAllocateHeap");
+  if (RtlReAllocateHeap_ptr == 0) {
+    puts("Couldn't find RtlReAllocateHeap");
+    return -1;
+  }
+
+  char *buffer;
+  SIZE_T buffer_size = 32;
+  SIZE_T new_buffer_size = buffer_size * 2;
+
+  buffer = (char*)RtlAllocateHeap_ptr(GetProcessHeap(), HEAP_ZERO_MEMORY, buffer_size);
+  assert(buffer != nullptr);
+  // Check that the buffer is zeroed.
+  for (SIZE_T i = 0; i < buffer_size; ++i) {
+    assert(buffer[i] == 0);
+  }
+  memset(buffer, 0xcc, buffer_size);
+
+  // Zero the newly allocated memory.
+  buffer = (char*)RtlReAllocateHeap_ptr(GetProcessHeap(), HEAP_ZERO_MEMORY, buffer, new_buffer_size);
+  assert(buffer != nullptr);
+  // Check that the first part of the buffer still has the old contents.
+  for (SIZE_T i = 0; i < buffer_size; ++i) {
+    assert(buffer[i] == (char)0xcc);
+  }
+  // Check that the new part of the buffer is zeroed.
+  for (SIZE_T i = buffer_size; i < new_buffer_size; ++i) {
+    assert(buffer[i] == 0x0);
+  }
+
+  // Shrink the buffer back down.
+  buffer = (char*)RtlReAllocateHeap_ptr(GetProcessHeap(), HEAP_ZERO_MEMORY, buffer, buffer_size);
+  assert(buffer != nullptr);
+  // Check that the first part of the buffer still has the old contents.
+  for (SIZE_T i = 0; i < buffer_size; ++i) {
+    assert(buffer[i] == (char)0xcc);
+  }
+
+  buffer[buffer_size + 1] = 'a';
+// CHECK: AddressSanitizer: heap-buffer-overflow on address [[ADDR:0x[0-9a-f]+]]
+// CHECK: WRITE of size 1 at [[ADDR]] thread T0
+}