Enable TestReadMemCString on non-darwin targets

The test works fine on linux, and I believe other targets should not
have an issue with as well. If they do, we can start blacklisting
instead of whitelisting.

The idea of using "-1" as the value of the pointer on non-apple targets
backfired, as it fails the "address != LLDB_INVALID_ADDRESS" test (-1 is
the value of LLDB_INVALID_ADDRESS).  However, it should be safe to use
0x100 for other targets as well. The first page of memory is generally
kept unreadable to catch null pointer dereferences.

llvm-svn: 321353

2 files changed, 4 insertions, 11 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/python_api/process/read-mem-cstring/TestReadMemCString.py b/lldb/packages/Python/lldbsuite/test/python_api/process/read-mem-cstring/TestReadMemCString.py
index e99779a5789..6302711606c 100644
--- a/lldb/packages/Python/lldbsuite/test/python_api/process/read-mem-cstring/TestReadMemCString.py
+++ b/lldb/packages/Python/lldbsuite/test/python_api/process/read-mem-cstring/TestReadMemCString.py
@@ -12,13 +12,8 @@ from lldbsuite.test import lldbutil
 class TestReadMemCString(TestBase):
 
     mydir = TestBase.compute_mydir(__file__)
+    NO_DEBUG_INFO_TESTCASE = True
 
-    def setUp(self):
-        TestBase.setUp(self)
-
-    # Need to have a char* pointer that points to unmapped memory to run
-    # this test on other platforms -- Darwin only for now.
-    @skipUnlessDarwin
     def test_read_memory_c_string(self):
         """Test corner case behavior of SBProcess::ReadCStringFromMemory"""
         self.build()
diff --git a/lldb/packages/Python/lldbsuite/test/python_api/process/read-mem-cstring/main.c b/lldb/packages/Python/lldbsuite/test/python_api/process/read-mem-cstring/main.c
index 94916997ad3..03c66741712 100644
--- a/lldb/packages/Python/lldbsuite/test/python_api/process/read-mem-cstring/main.c
+++ b/lldb/packages/Python/lldbsuite/test/python_api/process/read-mem-cstring/main.c
@@ -3,11 +3,9 @@ int main ()
 {
    const char *empty_string = "";
    const char *one_letter_string = "1";
-#if defined (__APPLE__)
-   const char *invalid_memory_string = (char*)0x100; // lower 4k is always PAGEZERO & unreadable on darwin
-#else
-   const char *invalid_memory_string = -1ULL; // maybe an invalid address on other platforms?
-#endif
+   // This expects that lower 4k of memory will be mapped unreadable, which most
+   // OSs do (to catch null pointer dereferences).
+   const char *invalid_memory_string = (char*)0x100;
 
    return empty_string[0] + one_letter_string[0]; // breakpoint here
 }