[lldb] Add missing space in C string format memory read warning

[DavidSpickett]

Summary

Also add tests to check that we print the warning in the right
circumstances.

[DavidSpickett]

Put the command in a string and add in the size each time since that's all that changes.

lldb/source/Commands/CommandObjectMemory.cpp

 //===-- CommandObjectMemory.cpp -------------------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
if (compiler_type.GetOpaqueQualType()) {
           result.AppendErrorWithFormat(
               "failed to read memory from 0x%" PRIx64 ".\n", addr);
           return false;
         }
 
         if (item_byte_size == read) {
           result.AppendWarningWithFormat(
               "unable to find a NULL terminated string at 0x%" PRIx64
-              ".Consider increasing the maximum read length.\n",
+              ". Consider increasing the maximum read length.\n",
               data_addr);
           --read;
           break_on_no_NULL = true;
         } else
           ++read; // account for final NULL byte
 
         memcpy(data_ptr, &buffer[0], read);
         data_ptr += read;

lldb/test/API/commands/memory/read/Makefile

+C_SOURCES := main.c
+
+include Makefile.rules

lldb/test/API/commands/memory/read/TestMemoryRead.py

+"""
+Test the 'memory read' command.
+"""
+
+import lldb
+import lldbsuite.test.lldbutil as lldbutil
+
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+
+
+class MemoryWriteTestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    def setUp(self):
+        # Call super's setUp().
+        TestBase.setUp(self)
+        # Find the line number to break inside main().
+        self.line = line_number('main.c', '// Set break point at this line.')
+
+    def build_run_stop(self):
+        self.build()
+        exe = self.getBuildArtifact("a.out")
+        self.runCmd("file " + exe, CURRENT_EXECUTABLE_SET)
+
+        # Break in main() after the variables are assigned values.
+        lldbutil.run_break_set_by_file_and_line(self,
+                                                "main.c",
+                                                self.line,
+                                                num_expected_locations=1,
+                                                loc_exact=True)
+
+        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'])
+
+        # The breakpoint should have a hit count of 1.
+        lldbutil.check_breakpoint(self, bpno = 1, expected_hit_count = 1)
+
+    @no_debug_info_test
+    def test_memory_read_c_string(self):
+        """Test that reading memory as a c string respects the size limit given
+           and warns if the null terminator is missing."""
+        self.build_run_stop()
+
+        # The size here is the size in memory so it includes the null terminator.
+        cmd = "memory read --format \"c-string\" --size {} &the_string"
+
+        # Size matches the size of the array.
+        self.expect(cmd.format(5), substrs=['\"abcd\"'])
+
+        # If size would take us past the terminator we stop at the terminator.
+        self.expect(cmd.format(10), substrs=['\"abcd\"'])
+
+        # Size 3 means 2 chars and a terminator. So we print 2 chars but warn because
+        # the third isn't 0 as expected.
+        self.expect(cmd.format(3), substrs=['\"ab\"'])
+        self.assertRegex(self.res.GetError(),
+            "unable to find a NULL terminated string at 0x[0-9A-fa-f]+."
+            " Consider increasing the maximum read length.")

lldb/test/API/commands/memory/read/main.c

+int main() {
+  char the_string[] = {'a', 'b', 'c', 'd', 0};
+  return 0; // Set break point at this line.
+}