BreakpointResolverFileLine: Restrict move-to-nearest-code from moving across function boundaries

Summary:
This fixes the case where a user tries to set a breakpoint on a source
line outside of any function (e.g. because that code is #ifdefed out, or
the compiler did not emit code for the function, etc.) and we would
silently move the breakpoint to the next function.

Now we check whether the line range of the resolved symbol context
function matches the original line number. We reject any breakpoint
locations that appear to move the breakpoint into a new function. This
filtering only happens if we have full debug info available (e.g. in
case of -gline-tables-only compilation, we still set the breakpoint on
the nearest source line).

Reviewers: jingham

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D30817

llvm-svn: 297817

5 files changed, 84 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/Makefile b/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/Makefile
new file mode 100644
index 00000000000..e7a1cab7e19
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/Makefile
@@ -0,0 +1,8 @@
+LEVEL = ../../../make
+
+DYLIB_NAME := foo
+DYLIB_CXX_SOURCES := foo.cpp
+CXX_SOURCES := main.cpp
+CFLAGS_EXTRAS += -fPIC
+
+include $(LEVEL)/Makefile.rules
diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/TestMoveNearest.py b/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/TestMoveNearest.py
new file mode 100644
index 00000000000..ae58ad9960d
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/TestMoveNearest.py
@@ -0,0 +1,58 @@
+from __future__ import print_function
+
+
+import unittest2
+import lldb
+from lldbsuite.test.lldbtest import *
+import lldbsuite.test.lldbutil as lldbutil
+
+
+class TestMoveNearest(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+    NO_DEBUG_INFO_TESTCASE = True
+
+    def setUp(self):
+        # Call super's setUp().
+        TestBase.setUp(self)
+        # Find the line number to break inside main().
+        self.line1 = line_number('foo.h', '// !BR1')
+        self.line2 = line_number('foo.h', '// !BR2')
+        self.line_main = line_number('main.cpp', '// !BR_main')
+
+    def test(self):
+        """Test target.move-to-nearest logic"""
+
+        self.build()
+        target = self.dbg.CreateTarget("a.out")
+        self.assertTrue(target, VALID_TARGET)
+
+        # Regardless of the -m value the breakpoint should have exactly one
+        # location on the foo functions
+        self.runCmd("settings set target.move-to-nearest-code true")
+        lldbutil.run_break_set_by_file_and_line(self, 'foo.h', self.line1,
+                loc_exact=True, extra_options="-m 1")
+        lldbutil.run_break_set_by_file_and_line(self, 'foo.h', self.line2,
+                loc_exact=True, extra_options="-m 1")
+
+        self.runCmd("settings set target.move-to-nearest-code false")
+        lldbutil.run_break_set_by_file_and_line(self, 'foo.h', self.line1,
+                loc_exact=True, extra_options="-m 0")
+        lldbutil.run_break_set_by_file_and_line(self, 'foo.h', self.line2,
+                loc_exact=True, extra_options="-m 0")
+
+
+        # Make sure we set a breakpoint in main with -m 1 for various lines in
+        # the function declaration
+        # "int"
+        lldbutil.run_break_set_by_file_and_line(self, 'main.cpp',
+                self.line_main-1, extra_options="-m 1")
+        # "main()"
+        lldbutil.run_break_set_by_file_and_line(self, 'main.cpp',
+                self.line_main, extra_options="-m 1")
+        # "{"
+        lldbutil.run_break_set_by_file_and_line(self, 'main.cpp',
+                self.line_main+1, extra_options="-m 1")
+        # "return .."
+        lldbutil.run_break_set_by_file_and_line(self, 'main.cpp',
+                self.line_main+2, extra_options="-m 1")
diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/foo.cpp b/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/foo.cpp
new file mode 100644
index 00000000000..8dad0a23f36
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/foo.cpp
@@ -0,0 +1,3 @@
+#include "foo.h"
+
+int call_foo1() { return foo1(); }
diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/foo.h b/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/foo.h
new file mode 100644
index 00000000000..060b91f5a5e
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/foo.h
@@ -0,0 +1,6 @@
+LLDB_TEST_API inline int foo1() { return 1; } // !BR1
+
+LLDB_TEST_API inline int foo2() { return 2; } // !BR2
+
+LLDB_TEST_API extern int call_foo1();
+LLDB_TEST_API extern int call_foo2();
diff --git a/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/main.cpp b/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/main.cpp
new file mode 100644
index 00000000000..c9295a5c7d3
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/functionalities/breakpoint/move_nearest/main.cpp
@@ -0,0 +1,9 @@
+#include "foo.h"
+
+int call_foo2() { return foo2(); }
+
+int
+main() // !BR_main
+{
+  return call_foo1() + call_foo2();
+}