[compiler-rt] Make the UBSan coverage-levels.cc test be Linux specific

[kubamracek]

Summary

The ubsan/TestCases/Misc/coverage-levels.cc is currently broken in the OS X buildbot: http://lab.llvm.org:8080/green/job/clang-stage1-cmake-RA_check/2144/console

However, XFAIL: darwin is not enough, because it fails only on i386, but not on x86_64. Let's move the test into a Linux/ subdirectory to make it not run on Darwin at all.

[samsonov]

Do you understand why it fails on x86_64?

[kubamracek]

In D8278#139480, @samsonov wrote:

Do you understand why it fails on x86_64?

Yes, I already sent it into the mailing list:

I believe this recent change (r231413) caused a subtle change in behavior that is causing a test failure on the Darwin buildbot at http://lab.llvm.org:8080/green/job/clang-stage1-cmake-RA_check/2083/console. The test is failing for a few days already, but it’s hard to tell which exact patch caused the regression, because the bot was offline for a day and a half when it occurred.

I think the cause is this: The old code in CovDump() iterates over the process map, but it intentionally skips over segments that are not executable. The new code in DumpOffsets() asks GetModuleNameAndOffsetForPC instead, which contains a bug/feature that is triggered for in a 64-bit binary when a 4GB __PAGEZERO (with protection=0) segment is present. In that case GetModuleNameAndOffsetForPC will say that the resulting offset is larger than 4GB, and the subsequent check in DumpOffsets that asserts offset > 0xffffffffU will ignore that item and not print it into the coverage file.

I also realized that simply ignoring __PAGEZERO in the Darwin implementation of process maps is not going to work easily, because there seems to be other code that relies on this behavior (I can’t tell if that’s a bug or a feature). What do you think would be way to fix this?

This patch is based on Kostya's suggestion to disable the test on Mac (it's already marked with XFAIL: darwin anyway).

[samsonov]

LGTM

[samsonov]

test/ubsan/TestCases/Misc/Linux/coverage-levels.cc

17

Remove XFAIL: darwin now.

[kcc]

LGTM

[kubamracek]

Landed in r232025.

test/ubsan/TestCases/Misc/Linux/coverage-levels.cc

+// Test various levels of coverage
+//
+// RUN: mkdir -p %T/coverage-levels
+// RUN: OPT=coverage=1:verbosity=1:coverage_dir=%T/coverage-levels
+// RUN: %clangxx -fsanitize=shift                        -DGOOD_SHIFT=1 -O1 -fsanitize-coverage=1  %s -o %t
+// RUN: UBSAN_OPTIONS=$OPT ASAN_OPTIONS=$OPT %run %t 2>&1 | FileCheck %s --check-prefix=CHECK1 --check-prefix=CHECK_NOWARN
+// RUN: %clangxx -fsanitize=undefined                    -DGOOD_SHIFT=1 -O1 -fsanitize-coverage=1  %s -o %t
+// RUN: UBSAN_OPTIONS=$OPT ASAN_OPTIONS=$OPT %run %t 2>&1 | FileCheck %s --check-prefix=CHECK1 --check-prefix=CHECK_NOWARN
+
+// RUN: %clangxx -fsanitize=shift -O1 -fsanitize-coverage=1  %s -o %t
+// RUN: UBSAN_OPTIONS=$OPT ASAN_OPTIONS=$OPT %run %t 2>&1 | FileCheck %s --check-prefix=CHECK1 --check-prefix=CHECK_WARN
+// RUN: %clangxx -fsanitize=shift -O1 -fsanitize-coverage=2  %s -o %t
+// RUN: UBSAN_OPTIONS=$OPT ASAN_OPTIONS=$OPT %run %t 2>&1 | FileCheck %s --check-prefix=CHECK2 --check-prefix=CHECK_WARN
+// RUN: %clangxx -fsanitize=shift -O1 -fsanitize-coverage=3  %s -o %t
+// RUN: UBSAN_OPTIONS=$OPT ASAN_OPTIONS=$OPT %run %t 2>&1 | FileCheck %s --check-prefix=CHECK3 --check-prefix=CHECK_WARN
+
+// XFAIL: darwin
+
+volatile int sink;
+int main(int argc, char **argv) {
+  int shift = argc * 32;
+#if GOOD_SHIFT
+  shift = 3;
+#endif
+  if ((argc << shift) == 16)  // False.
+    return 1;
+  return 0;
+}
+
+// CHECK_WARN: shift exponent 32 is too large
+// CHECK_NOWARN-NOT: ERROR
+// FIXME: Currently, coverage instrumentation kicks in after ubsan, so we get
+// more than the minimal number of instrumented blocks.
+// FIXME: Currently, ubsan with -fno-sanitize-recover and w/o asan will fail
+// to dump coverage.
+// CHECK1:  1 PCs written
+// CHECK2:  3 PCs written
+// CHECK3:  4 PCs written

test/ubsan/TestCases/Misc/Linux/lit.local.cfg

+def getRoot(config):
+  if not config.parent:
+    return config
+  return getRoot(config.parent)
+
+root = getRoot(config)
+
+if root.host_os not in ['Linux']:
+  config.unsupported = True

test/ubsan/TestCases/Misc/coverage-levels.cc

-// Test various levels of coverage
-//
-// RUN: mkdir -p %T/coverage-levels
-// RUN: OPT=coverage=1:verbosity=1:coverage_dir=%T/coverage-levels
-// RUN: %clangxx -fsanitize=shift                        -DGOOD_SHIFT=1 -O1 -fsanitize-coverage=1  %s -o %t
-// RUN: UBSAN_OPTIONS=$OPT ASAN_OPTIONS=$OPT %run %t 2>&1 | FileCheck %s --check-prefix=CHECK1 --check-prefix=CHECK_NOWARN
-// RUN: %clangxx -fsanitize=undefined                    -DGOOD_SHIFT=1 -O1 -fsanitize-coverage=1  %s -o %t
-// RUN: UBSAN_OPTIONS=$OPT ASAN_OPTIONS=$OPT %run %t 2>&1 | FileCheck %s --check-prefix=CHECK1 --check-prefix=CHECK_NOWARN
-
-// RUN: %clangxx -fsanitize=shift -O1 -fsanitize-coverage=1  %s -o %t
-// RUN: UBSAN_OPTIONS=$OPT ASAN_OPTIONS=$OPT %run %t 2>&1 | FileCheck %s --check-prefix=CHECK1 --check-prefix=CHECK_WARN
-// RUN: %clangxx -fsanitize=shift -O1 -fsanitize-coverage=2  %s -o %t
-// RUN: UBSAN_OPTIONS=$OPT ASAN_OPTIONS=$OPT %run %t 2>&1 | FileCheck %s --check-prefix=CHECK2 --check-prefix=CHECK_WARN
-// RUN: %clangxx -fsanitize=shift -O1 -fsanitize-coverage=3  %s -o %t
-// RUN: UBSAN_OPTIONS=$OPT ASAN_OPTIONS=$OPT %run %t 2>&1 | FileCheck %s --check-prefix=CHECK3 --check-prefix=CHECK_WARN
-
-// XFAIL: darwin
-
-volatile int sink;
-int main(int argc, char **argv) {
-  int shift = argc * 32;
-#if GOOD_SHIFT
-  shift = 3;
-#endif
-  if ((argc << shift) == 16)  // False.
-    return 1;
-  return 0;
-}
-
-// CHECK_WARN: shift exponent 32 is too large
-// CHECK_NOWARN-NOT: ERROR
-// FIXME: Currently, coverage instrumentation kicks in after ubsan, so we get
-// more than the minimal number of instrumented blocks.
-// FIXME: Currently, ubsan with -fno-sanitize-recover and w/o asan will fail
-// to dump coverage.
-// CHECK1:  1 PCs written
-// CHECK2:  3 PCs written
-// CHECK3:  4 PCs written