Fix ARM/AArch64 Step-Over watchpoint issue remove provision for duplicate watchpoints

This patch fixes ARM/AArch64 watchpoint bug which was taking inferior out of control while stepping over watchpoints.
Also adds a test case that tests above problem.

Differential revision: https://reviews.llvm.org/D25057

llvm-svn: 284706

3 files changed, 131 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/watchpoint/multi_watchpoint_slots/Makefile b/lldb/packages/Python/lldbsuite/test/functionalities/watchpoint/multi_watchpoint_slots/Makefile
new file mode 100644
index 00000000000..b09a579159d
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/watchpoint/multi_watchpoint_slots/Makefile
@@ -0,0 +1,5 @@
+LEVEL = ../../../make
+
+C_SOURCES := main.c
+
+include $(LEVEL)/Makefile.rules
diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/watchpoint/multi_watchpoint_slots/TestWatchpointMultipleSlots.py b/lldb/packages/Python/lldbsuite/test/functionalities/watchpoint/multi_watchpoint_slots/TestWatchpointMultipleSlots.py
new file mode 100644
index 00000000000..2e58cb893b7
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/watchpoint/multi_watchpoint_slots/TestWatchpointMultipleSlots.py
@@ -0,0 +1,97 @@
+"""
+Test watchpoint slots we should not be able to install multiple watchpoints
+within same word boundary. We should be able to install individual watchpoints
+on any of the bytes, half-word, or word. This is only for ARM/AArch64 targets.
+"""
+
+from __future__ import print_function
+
+import os
+import time
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class WatchpointSlotsTestCase(TestBase):
+    NO_DEBUG_INFO_TESTCASE = True
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    def setUp(self):
+        # Call super's setUp().
+        TestBase.setUp(self)
+
+        # Source filename.
+        self.source = 'main.c'
+
+        # Output filename.
+        self.exe_name = 'a.out'
+        self.d = {'C_SOURCES': self.source, 'EXE': self.exe_name}
+
+    # Watchpoints not supported
+    @expectedFailureAndroid(archs=['arm', 'aarch64'])
+    # This is a arm and aarch64 specific test case. No other architectures tested.
+    @skipIf(archs=no_match(['arm', 'aarch64']))
+    def test_multiple_watchpoints_on_same_word(self):
+
+        self.build(dictionary=self.d)
+        self.setTearDownCleanup(dictionary=self.d)
+
+        exe = os.path.join(os.getcwd(), self.exe_name)
+        self.runCmd("file " + exe, CURRENT_EXECUTABLE_SET)
+
+        # Detect line number after which we are going to increment arrayName.
+        loc_line = line_number('main.c', '// About to write byteArray')
+
+        # Set a breakpoint on the line detected above.
+        lldbutil.run_break_set_by_file_and_line(
+            self, "main.c", loc_line, num_expected_locations=1, loc_exact=True)
+
+        # Run the program.
+        self.runCmd("run", RUN_SUCCEEDED)
+
+        # The stop reason of the thread should be breakpoint.
+        self.expect("thread list", STOPPED_DUE_TO_BREAKPOINT,
+                     substrs=['stopped', 'stop reason = breakpoint'])
+
+        # Delete breakpoint we just hit.
+        self.expect("breakpoint delete 1", substrs=['1 breakpoints deleted'])
+
+        # Set a watchpoint at byteArray[0]
+        self.expect("watchpoint set variable byteArray[0]", WATCHPOINT_CREATED,
+                    substrs=['Watchpoint created','size = 1'])
+
+        # Use the '-v' option to do verbose listing of the watchpoint.
+        # The hit count should be 0 initially.
+        self.expect("watchpoint list -v 1", substrs=['hit_count = 0'])
+
+        # Try setting a watchpoint at byteArray[1]
+        self.expect("watchpoint set variable byteArray[1]", error=True,
+                    substrs=['Watchpoint creation failed'])
+
+        self.runCmd("process continue")
+
+        # We should be stopped due to the watchpoint.
+        # The stop reason of the thread should be watchpoint.
+        self.expect("thread list", STOPPED_DUE_TO_WATCHPOINT,
+                    substrs=['stopped', 'stop reason = watchpoint 1'])
+
+        # Delete the watchpoint we hit above successfully.
+        self.expect("watchpoint delete 1", substrs=['1 watchpoints deleted'])
+
+        # Set a watchpoint at byteArray[3]
+        self.expect("watchpoint set variable byteArray[3]", WATCHPOINT_CREATED,
+                    substrs=['Watchpoint created','size = 1'])
+   
+        # Resume inferior.
+        self.runCmd("process continue")
+
+        # We should be stopped due to the watchpoint.
+        # The stop reason of the thread should be watchpoint.
+        self.expect("thread list -v", STOPPED_DUE_TO_WATCHPOINT,
+                    substrs=['stopped', 'stop reason = watchpoint 3'])
+   
+        # Resume inferior.
+        self.runCmd("process continue")
diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/watchpoint/multi_watchpoint_slots/main.c b/lldb/packages/Python/lldbsuite/test/functionalities/watchpoint/multi_watchpoint_slots/main.c
new file mode 100644
index 00000000000..fd14a9b353f
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/watchpoint/multi_watchpoint_slots/main.c
@@ -0,0 +1,29 @@
+//===-- main.c --------------------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+#include <stdio.h>
+#include <stdint.h>
+
+uint64_t pad0 = 0;
+uint8_t byteArray[4] = {0};
+uint64_t pad1 = 0;
+
+int main(int argc, char** argv) {
+
+    int i;
+
+    for (i = 0; i < 4; i++)
+    {
+        printf("About to write byteArray[%d] ...\n", i); // About to write byteArray
+        pad0++;
+        byteArray[i] = 7;
+        pad1++;
+    }
+
+    return 0;
+}