[sanitizers] [windows] Use InternalMmapVector instead of silencing -Wframe-larger-than

[mstorsjo]

Summary

Also use this in ReadBinaryName which currently is producing warnings.

Keep pragmas for silencing warnings in sanitizer_unwind_win.cpp, as that can be called more frequently.

I haven't run tests for this (I don't have a setup yet where they'd run), but I'd appreciate if someone with such a setup available could run them.

[mstorsjo]

Updated patch that actually does apply on main instead of on top of the other one (from D97579).

[vitalybuka]

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_win.cpp

140

Can you do InternalMmapVector<PSYMBOL_INFO> ?

[mstorsjo]

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_win.cpp

140

Not really, this a struct followed by a flexible array.

[vitalybuka]

compiler-rt/lib/sanitizer_common/sanitizer_unwind_win.cpp

50

This called unwind slow and usually called infrequently, but user can
set fast_unwind_on_malloc=false and make it frequent.
So it's not nice that we make it slower.

You can try:

NOINLINE
static void UnwindSlowInternal(uptr pc, void *context, u32 max_depth, STACKFRAME64*) {
}

void BufferedStackTrace::UnwindSlow(uptr pc, void *context, u32 max_depth) {
  CONTEXT ctx = *(CONTEXT *)context;
  STACKFRAME64 stack_frame;
  UnwindSlowInternal(...., &stack_frame)
}

And also I don't know if all these are worth of hassle. Maybe we can just raise limit for -Wframe-larger-than=

[rnk]

compiler-rt/lib/sanitizer_common/sanitizer_unwind_win.cpp

50

Windows doesn't use the fast unwind path at all, so actually we come here every time we capture a stack trace for a heap event. See:
https://github.com/llvm/llvm-project/blob/main/compiler-rt/lib/sanitizer_common/sanitizer_stacktrace.h#L26

#elif SANITIZER_WINDOWS
# define SANITIZER_CAN_FAST_UNWIND 0

There are probably much faster ways to walk the stack, if someone was really motivated to maintain Windows ASan.

For now we should probably just revert this change. All the other changes seem like they should happen at most once: either during startup or during error reporting, so I'd keep them.

[mstorsjo]

Removed the changes to sanitizer_unwind_win.cpp, applied the suggested clang-format.

[mcgov]

Can we add @cbezault to this? He's the DevDiv vclibs person who owns Windows ASan going forward

[mstorsjo]

Can someone with a working windows sanitizers try this one out?

[russell.gallop]

In D97726#2612212, @mstorsjo wrote:

Can someone with a working windows sanitizers try this one out?

I applied this to cf806d91d562736192f91478eb47daa29c2230bf, built with VS2019 and ran some tests.

ninja check-sanitizer was okay
ninja check-ubsan had a few failures

These weren't present with the patch.

FAIL: UBSan-Standalone-x86_64 :: TestCases/Integer/suppressions.cpp (31 of 82)
******************** TEST 'UBSan-Standalone-x86_64 :: TestCases/Integer/suppressions.cpp' FAILED ********************
Script:
--
: 'RUN: at line 1';      F:/git/llvm-project/stage1/./bin/clang.exe      -fsanitize=integer -g0 F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp -o F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp
: 'RUN: at line 11';   env UBSAN_OPTIONS=halt_on_error=1 not  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp
: 'RUN: at line 13';   echo "signed-integer-overflow:F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp" > F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.wrong-supp
: 'RUN: at line 14';   env UBSAN_OPTIONS=halt_on_error=1:suppressions='"F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.wrong-supp"' not  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp
: 'RUN: at line 16';   echo "unsigned-integer-overflow:do_overflow" > F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.func-supp
: 'RUN: at line 17';   env UBSAN_OPTIONS=halt_on_error=1:suppressions='"F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.func-supp"'  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp
: 'RUN: at line 21';   echo "unsigned-integer-overflow:suppressions.cpp.tmp" > F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.module-supp
: 'RUN: at line 22';   env UBSAN_OPTIONS=halt_on_error=1:suppressions='"F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.module-supp"'  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp
: 'RUN: at line 25';   echo "unsigned-integer-overflow:F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp" > F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.file-supp
: 'RUN: at line 26';   env UBSAN_OPTIONS=halt_on_error=1:suppressions='"F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.file-supp"'  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp
: 'RUN: at line 29';      F:/git/llvm-project/stage1/./bin/clang.exe      -fsanitize=integer -fno-sanitize-recover=integer F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp -o F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp-norecover
: 'RUN: at line 30';   env UBSAN_OPTIONS=halt_on_error=1:suppressions='"F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.module-supp"' not  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp-norecover 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp
--
Exit Code: 1

Command Output (stdout):
--
$ ":" "RUN: at line 1"
$ "F:/git/llvm-project/stage1/./bin/clang.exe" "-fsanitize=integer" "-g0" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp" "-o" "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp"
# command output:
   Creating library F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.lib and object F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.exp

$ ":" "RUN: at line 11"
$ "env" "UBSAN_OPTIONS=halt_on_error=1" "not" "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp"
$ ":" "RUN: at line 13"
$ "echo" "signed-integer-overflow:F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp"
$ ":" "RUN: at line 14"
$ "env" "UBSAN_OPTIONS=halt_on_error=1:suppressions="F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.wrong-supp"" "not" "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp"
$ ":" "RUN: at line 16"
$ "echo" "unsigned-integer-overflow:do_overflow"
$ ":" "RUN: at line 17"
$ "env" "UBSAN_OPTIONS=halt_on_error=1:suppressions="F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp.func-supp"" "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Integer\Output\suppressions.cpp.tmp"
# command stderr:
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp:35:44: runtime error: unsigned integer overflow: 10000000000000000000 + 9000000000000000000 cannot be represented in type 'unsigned long long'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Integer\suppressions.cpp:35:44 in

error: command failed with exit status: 1

--

********************
Testing:  0.. 10.. 20.. 30.. 40.. 50..
FAIL: UBSan-Standalone-x86_64 :: TestCases/Misc/missing_return.cpp (50 of 82)
******************** TEST 'UBSan-Standalone-x86_64 :: TestCases/Misc/missing_return.cpp' FAILED ********************
Script:
--
: 'RUN: at line 1';      F:/git/llvm-project/stage1/./bin/clang.exe      -fsanitize=return -gline-tables-only -gcodeview -gcolumn-info F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp -O3 -o F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.tmp
: 'RUN: at line 2';   not  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.tmp 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp
: 'RUN: at line 3';   env UBSAN_OPTIONS=print_stacktrace=1 not  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.tmp 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp --check-prefix=CHECK-STACKTRACE
--
Exit Code: 1

Command Output (stdout):
--
$ ":" "RUN: at line 1"
$ "F:/git/llvm-project/stage1/./bin/clang.exe" "-fsanitize=return" "-gline-tables-only" "-gcodeview" "-gcolumn-info" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp" "-O3" "-o" "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.tmp"
# command output:
   Creating library F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.lib and object F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.exp

# command stderr:
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp:8:24: warning: GCC does not allow 'noinline' attribute in this position on a function definition [-Wgcc-compat]
int f() __attribute__((noinline)) {
                       ^
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp:10:1: warning: non-void function does not return a value [-Wreturn-type]
}
^
2 warnings generated.

$ ":" "RUN: at line 2"
$ "not" "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.tmp"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp"
$ ":" "RUN: at line 3"
$ "env" "UBSAN_OPTIONS=print_stacktrace=1" "not" "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.tmp"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp" "--check-prefix=CHECK-STACKTRACE"
# command stderr:
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp:9:22: error: CHECK-STACKTRACE: expected string not found in input
// CHECK-STACKTRACE: #0 {{.*}}f{{.*}}missing_return.cpp:[[@LINE-1]]
                     ^
<stdin>:1:1: note: scanning from here
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp:8:5: runtime error: execution reached the end of a value-returning function without returning a value
^
<stdin>:1:1: note: with "@LINE-1" equal to "8"
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp:8:5: runtime error: execution reached the end of a value-returning function without returning a value
^
<stdin>:1:46: note: possible intended match here
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp:8:5: runtime error: execution reached the end of a value-returning function without returning a value
                                             ^

Input file: <stdin>
Check file: F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp

-dump-input=help explains the following input dump.

Input was:
<<<<<<
           1: F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\Misc\missing_return.cpp:8:5: runtime error: execution reached the end of a value-returning function without returning a value
check:9'0     X~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ error: no match found
check:9'1                                                                                                                                                                                         with "@LINE-1" equal to "8"
check:9'2                                                  ?                                                                                                                                      possible intended match
           2:  #0 0x7ff7d55c80cf (F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.tmp+0x80cf)
check:9'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           3:  #1 0x7ff7d55c80e8 (F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.tmp+0x80e8)
check:9'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           4:  #2 0x7ff7d55cb02b (F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\Misc\Output\missing_return.cpp.tmp+0xb02b)
check:9'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           5:  #3 0x7ffc0a8b7033 (C:\WINDOWS\System32\KERNEL32.DLL+0x17033)
check:9'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           6:  #4 0x7ffc0c69d240 (C:\WINDOWS\SYSTEM32\ntdll.dll+0x4d240)
check:9'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
           .
           .
           .
>>>>>>

error: command failed with exit status: 1

--

********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90.
FAIL: UBSan-Standalone-x86_64 :: TestCases/TypeCheck/misaligned.cpp (81 of 82)
******************** TEST 'UBSan-Standalone-x86_64 :: TestCases/TypeCheck/misaligned.cpp' FAILED ********************
Script:
--
: 'RUN: at line 1';      F:/git/llvm-project/stage1/./bin/clang.exe      -gline-tables-only -gcodeview -gcolumn-info -fsanitize=alignment F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp -O3 -o F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp
: 'RUN: at line 2';    F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp l0 &&  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp s0 &&  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp r0 &&  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp m0 &&  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp f0 &&  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp n0 &&  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp u0
: 'RUN: at line 3';    F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp l1 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp --check-prefix=CHECK-LOAD --strict-whitespace
: 'RUN: at line 4';    F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp r1 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp --check-prefix=CHECK-REFERENCE
: 'RUN: at line 5';    F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp m1 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp --check-prefix=CHECK-MEMBER
: 'RUN: at line 6';    F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp f1 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp --check-prefix=CHECK-MEMFUN
: 'RUN: at line 7';    F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp n1 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp --check-prefix=CHECK-NEW
: 'RUN: at line 8';    F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp u1 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp --check-prefix=CHECK-UPCAST
: 'RUN: at line 9';   env UBSAN_OPTIONS=print_stacktrace=1  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp l1 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp --check-prefix=CHECK-LOAD --check-prefix=CHECK-STACK-LOAD
: 'RUN: at line 11';      F:/git/llvm-project/stage1/./bin/clang.exe      -fsanitize=alignment -fno-sanitize-recover=alignment F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp -O3 -o F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp
: 'RUN: at line 12';   not  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp s1 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp --check-prefix=CHECK-STORE
: 'RUN: at line 13';   not  F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp w1 2>&1 | FileCheck F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp --check-prefix=CHECK-WILD
--
Exit Code: 1

Command Output (stdout):
--
$ ":" "RUN: at line 1"
$ "F:/git/llvm-project/stage1/./bin/clang.exe" "-gline-tables-only" "-gcodeview" "-gcolumn-info" "-fsanitize=alignment" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp" "-O3" "-o" "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp"
# command output:
   Creating library F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.lib and object F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.exp

# command stderr:
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:47:15: warning: use of logical '&&' with constant operand [-Wconstant-logical-operand]
    return *p && 0;
              ^  ~
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:47:15: note: use '&' for a bitwise operation
    return *p && 0;
              ^~
              &
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:47:15: note: remove constant to silence this warning
    return *p && 0;
             ~^~~~
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:71:17: warning: use of logical '&&' with constant operand [-Wconstant-logical-operand]
    return s->k && 0;
                ^  ~
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:71:17: note: use '&' for a bitwise operation
    return s->k && 0;
                ^~
                &
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:71:17: note: remove constant to silence this warning
    return s->k && 0;
               ~^~~~
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:78:19: warning: use of logical '&&' with constant operand [-Wconstant-logical-operand]
    return s->f() && 0;
                  ^  ~
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:78:19: note: use '&' for a bitwise operation
    return s->f() && 0;
                  ^~
                  &
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:78:19: note: remove constant to silence this warning
    return s->f() && 0;
                 ~^~~~
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:85:27: warning: use of logical '&&' with constant operand [-Wconstant-logical-operand]
    return (new (s) S)->k && 0;
                          ^  ~
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:85:27: note: use '&' for a bitwise operation
    return (new (s) S)->k && 0;
                          ^~
                          &
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:85:27: note: remove constant to silence this warning
    return (new (s) S)->k && 0;
                         ~^~~~
4 warnings generated.

$ ":" "RUN: at line 2"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "l0"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "s0"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "r0"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "m0"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "f0"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "n0"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "u0"
$ ":" "RUN: at line 3"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "l1"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp" "--check-prefix=CHECK-LOAD" "--strict-whitespace"
$ ":" "RUN: at line 4"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "r1"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp" "--check-prefix=CHECK-REFERENCE"
$ ":" "RUN: at line 5"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "m1"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp" "--check-prefix=CHECK-MEMBER"
$ ":" "RUN: at line 6"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "f1"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp" "--check-prefix=CHECK-MEMFUN"
$ ":" "RUN: at line 7"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "n1"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp" "--check-prefix=CHECK-NEW"
$ ":" "RUN: at line 8"
$ "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "u1"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp" "--check-prefix=CHECK-UPCAST"
$ ":" "RUN: at line 9"
$ "env" "UBSAN_OPTIONS=print_stacktrace=1" "F:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\Standalone-x86_64\TestCases\TypeCheck\Output\misaligned.cpp.tmp" "l1"
$ "FileCheck" "F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp" "--check-prefix=CHECK-LOAD" "--check-prefix=CHECK-STACK-LOAD"
# command stderr:
F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:48:23: error: CHECK-STACK-LOAD: expected string not found in input
 // CHECK-STACK-LOAD: #0 {{.*}}main{{.*}}misaligned.cpp
                      ^
<stdin>:4:3: note: scanning from here
 ^
  ^
<stdin>:5:109: note: possible intended match here
 #0 0x7ff6a5118273 (f:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\standalone-x86_64\testcases\typecheck\output\misaligned.cpp.tmp+0x8273)
                                                                                                            ^

Input file: <stdin>
Check file: F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            1: F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:47:12: runtime error: load of misaligned address 0x00bbbe32f9c5 for type 'int', which requires 4 byte alignment
            2: 0x00bbbe32f9c5: note: pointer points here
            3:  00 00 00 01 02 03 04 05 00 00 00 00 00 00 00 20 aa 71 d2 79 02 00 00 f0 e4 72 d2 79 02 00 00 00
            4:  ^
check:48'0       X~ error: no match found
            5:  #0 0x7ff6a5118273 (f:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\standalone-x86_64\testcases\typecheck\output\misaligned.cpp.tmp+0x8273)
check:48'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:48'1                                                                                                                 ?                                           possible intended match
            6:  #1 0x7ff6a511b27b (f:\git\llvm-project\stage1\projects\compiler-rt\test\ubsan\standalone-x86_64\testcases\typecheck\output\misaligned.cpp.tmp+0xb27b)
check:48'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            7:  #2 0x7ffc0a8b7033 (C:\WINDOWS\System32\KERNEL32.DLL+0x17033)
check:48'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            8:  #3 0x7ffc0c69d240 (C:\WINDOWS\SYSTEM32\ntdll.dll+0x4d240)
check:48'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
            9:
check:48'0     ~
           10: SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior F:\git\llvm-project\compiler-rt\test\ubsan\TestCases\TypeCheck\misaligned.cpp:47:12 in
check:48'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>>>>>

error: command failed with exit status: 1

--

********************
Testing:  0.. 10.. 20.. 30.. 40.. 50.. 60.. 70.. 80.. 90..
********************
Failed Tests (3):
  UBSan-Standalone-x86_64 :: TestCases/Integer/suppressions.cpp
  UBSan-Standalone-x86_64 :: TestCases/Misc/missing_return.cpp
  UBSan-Standalone-x86_64 :: TestCases/TypeCheck/misaligned.cpp


Testing Time: 46.90s
  Unsupported      : 22
  Passed           : 55
  Expectedly Failed:  2
  Failed           :  3

[mstorsjo]

In D97726#2613816, @russell.gallop wrote:

In D97726#2612212, @mstorsjo wrote:

Can someone with a working windows sanitizers try this one out?

I applied this to cf806d91d562736192f91478eb47daa29c2230bf, built with VS2019 and ran some tests.

Thanks, much appreciated!

These weren't present with the patch.

I presume you meant weren't present without the patch?

Failed Tests (3):
  UBSan-Standalone-x86_64 :: TestCases/Integer/suppressions.cpp
  UBSan-Standalone-x86_64 :: TestCases/Misc/missing_return.cpp
  UBSan-Standalone-x86_64 :: TestCases/TypeCheck/misaligned.cpp

Can you pinpoint which one of the couple changes that is the one that breaks it? There's roughly four cases of buffers converted from plain stack buffer to InternalMmapVector with a bit of syntax changes around each.

[russell.gallop]

In D97726#2613898, @mstorsjo wrote:

These weren't present with the patch.

I presume you meant weren't present without the patch?

That's right, my typo. These weren't present without the patch.

Can you pinpoint which one of the couple changes that is the one that breaks it? There's roughly four cases of buffers converted from plain stack buffer to InternalMmapVector with a bit of syntax changes around each.

It appears to be the change in GetPreferredBase. Reverting just that change causes those ubsan tests to pass.

There are also a lot of failures with check-asan, I think undoing the change in GetPreferredBase fixes those as well.

[mstorsjo]

Thanks! That narrowed it down nicely.

compiler-rt/lib/sanitizer_common/sanitizer_win.cpp

597

Ah, this sizeof(buf) needs to be buf.size() or something like that.

[rnk]

(Thanks for running the tests, I started patching this in and setting up the build but didn't finish)

[mstorsjo]

Fixed one missed case of sizeof(buf)

[russell.gallop]

With an additional change from sizeof(buf) to buf.size() this fixes the check-asan and check-ubsan tests.

Note that there are 5 check-asan tests which fail for me with and without this patch:

AddressSanitizer-x86_64-windows :: TestCases/Windows/delay_dbghelp.cpp
AddressSanitizer-x86_64-windows :: TestCases/Windows/dll_host.cpp
AddressSanitizer-x86_64-windows :: TestCases/Windows/interface_symbols_windows.cpp
AddressSanitizer-x86_64-windows :: TestCases/Windows/iostream_sbo.cpp
AddressSanitizer-x86_64-windows :: TestCases/Windows/symbols_path.cpp

I don't have time to dig into these at the moment.

compiler-rt/lib/sanitizer_common/sanitizer_win.cpp

598

I think that this line needs changing from sizeof(buf) to buf.size() as well.

[mstorsjo]

Fixed another missed case of sizeof(buf) -> buf.size()

[mstorsjo]

compiler-rt/lib/sanitizer_common/sanitizer_win.cpp

598

Doh, thanks for catching it!, fixed now.

[mstorsjo]

@rnk - Does this look ok to you now? AFAIK it passes as many tests as before according to @russell.gallop.

[rnk]

compiler-rt/lib/sanitizer_common/sanitizer_win.cpp

642

This might be a micro-optimization, but InternalMmapVector is built on VirtualAlloc, which is expensive, and now it's being done three times in a loop over the DLLs in a process. That might matter for startup time. Can you hoist the vectors out of the loop? You'll have to pass in memory to GetPreferredBase, which leaks implementation details, but I think it's worth doing.

[mstorsjo]

Hoisted three InternalMmapVector out of a loop. I've managed to set up an environment where I can run the tests now, and the tests still pass as they did before.

[rnk]

lgtm

compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_win.cpp

#undef DBGHELP_IMPORT
   CHECK_NE(last_bslash, 0);
   *last_bslash = L'\0';
   if (!SymSetSearchPathW(GetCurrentProcess(), path_buffer)) {
     Report("*** WARNING: Failed to SymSetSearchPathW\n");
     return;
   }
 }
 
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wframe-larger-than="
-#endif
 bool WinSymbolizerTool::SymbolizePC(uptr addr, SymbolizedStack *frame) {
   InitializeDbgHelpIfNeeded();
 
   // See https://docs.microsoft.com/en-us/windows/win32/debug/retrieving-symbol-information-by-address
-  char buffer[sizeof(SYMBOL_INFO) + MAX_SYM_NAME * sizeof(CHAR)];
-  PSYMBOL_INFO symbol = (PSYMBOL_INFO)buffer;
+  InternalMmapVector<char> buffer(sizeof(SYMBOL_INFO) + MAX_SYM_NAME * sizeof(CHAR));
+  PSYMBOL_INFO symbol = (PSYMBOL_INFO)&buffer[0];
   symbol->SizeOfStruct = sizeof(SYMBOL_INFO);
   symbol->MaxNameLen = MAX_SYM_NAME;
   DWORD64 offset = 0;
   BOOL got_objname = SymFromAddr(GetCurrentProcess(),
                                  (DWORD64)addr, &offset, symbol);
   if (!got_objname)
     return false;
 
   DWORD unused;
   IMAGEHLP_LINE64 line_info;
   line_info.SizeOfStruct = sizeof(IMAGEHLP_LINE64);
   BOOL got_fileline = SymGetLineFromAddr64(GetCurrentProcess(), (DWORD64)addr,
                                            &unused, &line_info);
   frame->info.function = internal_strdup(symbol->Name);
   frame->info.function_offset = (uptr)offset;
   if (got_fileline) {
     frame->info.file = internal_strdup(line_info.FileName);
     frame->info.line = line_info.LineNumber;
   }
   // Only consider this a successful symbolization attempt if we got file info.
   // Otherwise, try llvm-symbolizer.
   return got_fileline;
 }
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
 
 const char *WinSymbolizerTool::Demangle(const char *name) {
   CHECK(is_dbghelp_initialized);
   static char demangle_buffer[1000];
   if (name[0] == '\01' &&
       UnDecorateSymbolName(name + 1, demangle_buffer, sizeof(demangle_buffer),
                            UNDNAME_NAME_ONLY))
     return demangle_buffer;

compiler-rt/lib/sanitizer_common/sanitizer_unwind_win.cpp

void BufferedStackTrace::UnwindSlow(uptr pc, u32 max_depth) {
   uptr pc_location = LocatePcInTrace(pc);
   PopStackFrames(pc_location);
 
   // Replace the first frame with the PC because the frame in the
   // stacktrace might be incorrect.
   trace_buffer[0] = pc;
 }
 
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wframe-larger-than="
-#endif
 void BufferedStackTrace::UnwindSlow(uptr pc, void *context, u32 max_depth) {
   CHECK(context);
   CHECK_GE(max_depth, 2);
-  CONTEXT ctx = *(CONTEXT *)context;
-  STACKFRAME64 stack_frame;
+  InternalMmapVector<CONTEXT> ctx_buf(1);
+  CONTEXT &ctx = ctx_buf[0];
+  ctx = *(CONTEXT *)context;
+  InternalMmapVector<STACKFRAME64> stack_frame_buf(1);
+  STACKFRAME64 &stack_frame = stack_frame_buf[0];
   memset(&stack_frame, 0, sizeof(stack_frame));
 
   InitializeDbgHelpIfNeeded();
 
   size = 0;
 #if defined(_WIN64)
   int machine_type = IMAGE_FILE_MACHINE_AMD64;
   stack_frame.AddrPC.Offset = ctx.Rip;
#endif
   stack_frame.AddrStack.Mode = AddrModeFlat;
   while (StackWalk64(machine_type, GetCurrentProcess(), GetCurrentThread(),
     &stack_frame, &ctx, NULL, SymFunctionTableAccess64,
     SymGetModuleBase64, NULL) &&
     size < Min(max_depth, kStackTraceMax)) {
     trace_buffer[size++] = (uptr)stack_frame.AddrPC.Offset;
   }
 }
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
 #endif  // #if !SANITIZER_GO
 
 #endif  // SANITIZER_WINDOWS

compiler-rt/lib/sanitizer_common/sanitizer_win.cpp

static uptr GetPreferredBase(const char *modname) {
   if (dos_header.e_magic != IMAGE_DOS_SIGNATURE)
     return 0;
 
   // The layout at e_lfanew is:
   // "PE\0\0"
   // IMAGE_FILE_HEADER
   // IMAGE_OPTIONAL_HEADER
   // Seek to e_lfanew and read all that data.
-  char buf[4 + sizeof(IMAGE_FILE_HEADER) + sizeof(IMAGE_OPTIONAL_HEADER)];
+  InternalMmapVector<char> buf(4 + sizeof(IMAGE_FILE_HEADER) + sizeof(IMAGE_OPTIONAL_HEADER));
   if (::SetFilePointer(fd, dos_header.e_lfanew, nullptr, FILE_BEGIN) ==
       INVALID_SET_FILE_POINTER)
     return 0;
   if (!ReadFromFile(fd, &buf[0], sizeof(buf), &bytes_read) ||
       bytes_read != sizeof(buf))
     return 0;
 
   // Check for "PE\0\0" before the PE header.
   char *pe_sig = &buf[0];
   if (internal_memcmp(pe_sig, "PE\0\0", 4) != 0)
     return 0;
 
   // Skip over IMAGE_FILE_HEADER. We could do more validation here if we wanted.
   IMAGE_OPTIONAL_HEADER *pe_header =
       (IMAGE_OPTIONAL_HEADER *)(pe_sig + 4 + sizeof(IMAGE_FILE_HEADER));
 
   // Check for more magic in the PE header.
   if (pe_header->Magic != IMAGE_NT_OPTIONAL_HDR_MAGIC)
     return 0;
 
   // Finally, return the ImageBase.
   return (uptr)pe_header->ImageBase;
 }
 
-#ifdef __clang__
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wframe-larger-than="
-#endif
 void ListOfModules::init() {
   clearOrInit();
   HANDLE cur_process = GetCurrentProcess();
 
   // Query the list of modules.  Start by assuming there are no more than 256
   // modules and retry if that's not sufficient.
   HMODULE *hmodules = 0;
   uptr modules_buffer_size = sizeof(HMODULE) * 256;
   DWORD bytes_required;
   while (!hmodules) {
     hmodules = (HMODULE *)MmapOrDie(modules_buffer_size, __FUNCTION__);
     CHECK(EnumProcessModules(cur_process, hmodules, modules_buffer_size,
                              &bytes_required));
     if (bytes_required > modules_buffer_size) {
       // Either there turned out to be more than 256 hmodules, or new hmodules
       // could have loaded since the last try.  Retry.
       UnmapOrDie(hmodules, modules_buffer_size);
       hmodules = 0;
       modules_buffer_size = bytes_required;
     }
   }
 
   // |num_modules| is the number of modules actually present,
   size_t num_modules = bytes_required / sizeof(HMODULE);
   for (size_t i = 0; i < num_modules; ++i) {
     HMODULE handle = hmodules[i];
     MODULEINFO mi;
     if (!GetModuleInformation(cur_process, handle, &mi, sizeof(mi)))
       continue;
 
     // Get the UTF-16 path and convert to UTF-8.
-    wchar_t modname_utf16[kMaxPathLength];
+    InternalMmapVector<wchar_t> modname_utf16(kMaxPathLength);
     int modname_utf16_len =
-        GetModuleFileNameW(handle, modname_utf16, kMaxPathLength);
+        GetModuleFileNameW(handle, &modname_utf16[0], kMaxPathLength);
     if (modname_utf16_len == 0)
       modname_utf16[0] = '\0';
-    char module_name[kMaxPathLength];
+    InternalMmapVector<char> module_name(kMaxPathLength);
     int module_name_len =
-        ::WideCharToMultiByte(CP_UTF8, 0, modname_utf16, modname_utf16_len + 1,
+        ::WideCharToMultiByte(CP_UTF8, 0, &modname_utf16[0], modname_utf16_len + 1,
                               &module_name[0], kMaxPathLength, NULL, NULL);
     module_name[module_name_len] = '\0';
 
     uptr base_address = (uptr)mi.lpBaseOfDll;
     uptr end_address = (uptr)mi.lpBaseOfDll + mi.SizeOfImage;
 
     // Adjust the base address of the module so that we get a VA instead of an
     // RVA when computing the module offset. This helps llvm-symbolizer find the
     // right DWARF CU. In the common case that the image is loaded at it's
     // preferred address, we will now print normal virtual addresses.
     uptr preferred_base = GetPreferredBase(&module_name[0]);
     uptr adjusted_base = base_address - preferred_base;
 
-    LoadedModule cur_module;
-    cur_module.set(module_name, adjusted_base);
+    modules_.push_back(LoadedModule());
+    LoadedModule &cur_module = modules_.back();
+    cur_module.set(&module_name[0], adjusted_base);
     // We add the whole module as one single address range.
     cur_module.addAddressRange(base_address, end_address, /*executable*/ true,
                                /*writable*/ true);
-    modules_.push_back(cur_module);
   }
   UnmapOrDie(hmodules, modules_buffer_size);
 }
-#ifdef __clang__
-#pragma clang diagnostic pop
-#endif
 
 void ListOfModules::fallbackInit() { clear(); }
 
 // We can't use atexit() directly at __asan_init time as the CRT is not fully
 // initialized at this point.  Place the functions into a vector and use
 // atexit() as soon as it is ready for use (i.e. after .CRT$XIC initializers).
 InternalMmapVectorNoCtor<void (*)(void)> atexit_functions;
 
const char *SignalContext::Describe() const {
   return "unknown exception";
 }
 
 uptr ReadBinaryName(/*out*/char *buf, uptr buf_len) {
   if (buf_len == 0)
     return 0;
 
   // Get the UTF-16 path and convert to UTF-8.
-  wchar_t binname_utf16[kMaxPathLength];
+  InternalMmapVector<wchar_t> binname_utf16(kMaxPathLength);
   int binname_utf16_len =
-      GetModuleFileNameW(NULL, binname_utf16, ARRAY_SIZE(binname_utf16));
+      GetModuleFileNameW(NULL, &binname_utf16[0], kMaxPathLength);
   if (binname_utf16_len == 0) {
     buf[0] = '\0';
     return 0;
   }
   int binary_name_len = ::WideCharToMultiByte(
-      CP_UTF8, 0, binname_utf16, binname_utf16_len, buf, buf_len, NULL, NULL);
+      CP_UTF8, 0, &binname_utf16[0], binname_utf16_len, buf, buf_len, NULL, NULL);
   if ((unsigned)binary_name_len == buf_len)
     --binary_name_len;
   buf[binary_name_len] = '\0';
   return binary_name_len;
 }
 
 uptr ReadLongProcessName(/*out*/char *buf, uptr buf_len) {
   return ReadBinaryName(buf, buf_len);