Added initial code completion support for the `expr` command

Summary:
This patch adds initial code completion support for the `expr` command.

We now have a completion handler in the expression CommandObject that
essentially just attempts to parse the given user expression with Clang with
an attached code completion consumer. We filter and prepare the
code completions provided by Clang and send them back to the completion
API.

The current completion is limited to variables that are in the current scope.
This includes local variables and all types used by local variables. We however
don't do any completion of symbols that are not used in the local scope (or
in some other way already in the ASTContext).

This is partly because there is not yet any code that manually searches for additiona
information in the debug information. Another cause is that for some reason the existing
code for loading these additional symbols when requested by Clang doesn't seem to work.
This will be fixed in a future patch.

Reviewers: jingham, teemperor

Reviewed By: teemperor

Subscribers: labath, aprantl, JDevlieghere, friss, lldb-commits

Differential Revision: https://reviews.llvm.org/D48465

llvm-svn: 341086

1 files changed, 227 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/expression_command/completion/TestExprCompletion.py b/lldb/packages/Python/lldbsuite/test/expression_command/completion/TestExprCompletion.py
new file mode 100644
index 00000000000..2ebc239fa08
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/expression_command/completion/TestExprCompletion.py
@@ -0,0 +1,227 @@
+"""
+Test the lldb command line completion mechanism for the 'expr' command.
+"""
+
+from __future__ import print_function
+
+import random
+import os
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbplatform
+from lldbsuite.test import lldbutil
+
+class CommandLineExprCompletionTestCase(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    NO_DEBUG_INFO_TESTCASE = True
+
+    @expectedFailureAll(oslist=["windows"], bugnumber="llvm.org/pr24489")
+    def test_expr_completion(self):
+        self.build()
+        self.main_source = "main.cpp"
+        self.main_source_spec = lldb.SBFileSpec(self.main_source)
+        self.dbg.CreateTarget(self.getBuildArtifact("a.out"))
+
+        # Try the completion before we have a context to complete on.
+        self.assume_no_completions('expr some_expr')
+        self.assume_no_completions('expr ')
+        self.assume_no_completions('expr f')
+
+
+        (target, process, thread, bkpt) = lldbutil.run_to_source_breakpoint(self,
+                                          '// Break here', self.main_source_spec)
+
+        # Completing member functions
+        self.complete_exactly('expr some_expr.FooNoArgs',
+                              'expr some_expr.FooNoArgsBar()')
+        self.complete_exactly('expr some_expr.FooWithArgs',
+                              'expr some_expr.FooWithArgsBar(')
+        self.complete_exactly('expr some_expr.FooWithMultipleArgs',
+                              'expr some_expr.FooWithMultipleArgsBar(')
+        self.complete_exactly('expr some_expr.FooUnderscore',
+                              'expr some_expr.FooUnderscoreBar_()')
+        self.complete_exactly('expr some_expr.FooNumbers',
+                              'expr some_expr.FooNumbersBar1()')
+        self.complete_exactly('expr some_expr.StaticMemberMethod',
+                              'expr some_expr.StaticMemberMethodBar()')
+
+        # Completing static functions
+        self.complete_exactly('expr Expr::StaticMemberMethod',
+                              'expr Expr::StaticMemberMethodBar()')
+
+        # Completing member variables
+        self.complete_exactly('expr some_expr.MemberVariab',
+                              'expr some_expr.MemberVariableBar')
+
+        # Multiple completions
+        self.completions_contain('expr some_expr.',
+                                 ['some_expr.FooNumbersBar1()',
+                                  'some_expr.FooUnderscoreBar_()',
+                                  'some_expr.FooWithArgsBar(',
+                                  'some_expr.MemberVariableBar'])
+
+        self.completions_contain('expr some_expr.Foo',
+                                 ['some_expr.FooNumbersBar1()',
+                                  'some_expr.FooUnderscoreBar_()',
+                                  'some_expr.FooWithArgsBar('])
+
+        self.completions_contain('expr ',
+                                 ['static_cast',
+                                  'reinterpret_cast',
+                                  'dynamic_cast'])
+
+        self.completions_contain('expr 1 + ',
+                                 ['static_cast',
+                                  'reinterpret_cast',
+                                  'dynamic_cast'])
+
+        # Completion expr without spaces
+        # This is a bit awkward looking for the user, but that's how
+        # the completion API works at the moment.
+        self.completions_contain('expr 1+',
+                                 ['1+some_expr', "1+static_cast"])
+
+        # Test with spaces
+        self.complete_exactly('expr   some_expr .FooNoArgs',
+                              'expr   some_expr .FooNoArgsBar()')
+        self.complete_exactly('expr  some_expr .FooNoArgs',
+                              'expr  some_expr .FooNoArgsBar()')
+        self.complete_exactly('expr some_expr .FooNoArgs',
+                              'expr some_expr .FooNoArgsBar()')
+        self.complete_exactly('expr some_expr. FooNoArgs',
+                              'expr some_expr. FooNoArgsBar()')
+        self.complete_exactly('expr some_expr . FooNoArgs',
+                              'expr some_expr . FooNoArgsBar()')
+        self.complete_exactly('expr Expr :: StaticMemberMethod',
+                              'expr Expr :: StaticMemberMethodBar()')
+        self.complete_exactly('expr Expr ::StaticMemberMethod',
+                              'expr Expr ::StaticMemberMethodBar()')
+        self.complete_exactly('expr Expr:: StaticMemberMethod',
+                              'expr Expr:: StaticMemberMethodBar()')
+
+        # Test that string literals don't break our parsing logic.
+        self.complete_exactly('expr const char *cstr = "some_e"; char c = *cst',
+                              'expr const char *cstr = "some_e"; char c = *cstr')
+        self.complete_exactly('expr const char *cstr = "some_e" ; char c = *cst',
+                              'expr const char *cstr = "some_e" ; char c = *cstr')
+        # Requesting completions inside an incomplete string doesn't provide any
+        # completions.
+        self.complete_exactly('expr const char *cstr = "some_e',
+                              'expr const char *cstr = "some_e')
+
+        # Completing inside double dash should do nothing
+        self.assume_no_completions('expr -i0 -- some_expr.', 10)
+        self.assume_no_completions('expr -i0 -- some_expr.', 11)
+
+        # Test with expr arguments
+        self.complete_exactly('expr -i0 -- some_expr .FooNoArgs',
+                              'expr -i0 -- some_expr .FooNoArgsBar()')
+        self.complete_exactly('expr  -i0 -- some_expr .FooNoArgs',
+                              'expr  -i0 -- some_expr .FooNoArgsBar()')
+
+        # Addrof and deref
+        self.complete_exactly('expr (*(&some_expr)).FooNoArgs',
+                              'expr (*(&some_expr)).FooNoArgsBar()')
+        self.complete_exactly('expr (*(&some_expr)) .FooNoArgs',
+                              'expr (*(&some_expr)) .FooNoArgsBar()')
+        self.complete_exactly('expr (* (&some_expr)) .FooNoArgs',
+                              'expr (* (&some_expr)) .FooNoArgsBar()')
+        self.complete_exactly('expr (* (& some_expr)) .FooNoArgs',
+                              'expr (* (& some_expr)) .FooNoArgsBar()')
+
+        # Addrof and deref (part 2)
+        self.complete_exactly('expr (&some_expr)->FooNoArgs',
+                              'expr (&some_expr)->FooNoArgsBar()')
+        self.complete_exactly('expr (&some_expr) ->FooNoArgs',
+                              'expr (&some_expr) ->FooNoArgsBar()')
+        self.complete_exactly('expr (&some_expr) -> FooNoArgs',
+                              'expr (&some_expr) -> FooNoArgsBar()')
+        self.complete_exactly('expr (&some_expr)-> FooNoArgs',
+                              'expr (&some_expr)-> FooNoArgsBar()')
+
+        # Builtin arg
+        self.complete_exactly('expr static_ca',
+                              'expr static_cast')
+
+        # From other files
+        self.complete_exactly('expr fwd_decl_ptr->Hidden',
+                              'expr fwd_decl_ptr->HiddenMember')
+
+
+        # Types
+        self.complete_exactly('expr LongClassNa',
+                              'expr LongClassName')
+        self.complete_exactly('expr LongNamespaceName::NestedCla',
+                              'expr LongNamespaceName::NestedClass')
+
+        # Namespaces
+        self.complete_exactly('expr LongNamespaceNa',
+                              'expr LongNamespaceName::')
+
+        # Multiple arguments
+        self.complete_exactly('expr &some_expr + &some_e',
+                              'expr &some_expr + &some_expr')
+        self.complete_exactly('expr SomeLongVarNameWithCapitals + SomeLongVarName',
+                              'expr SomeLongVarNameWithCapitals + SomeLongVarNameWithCapitals')
+        self.complete_exactly('expr SomeIntVar + SomeIntV',
+                              'expr SomeIntVar + SomeIntVar')
+
+        # Multiple statements
+        self.complete_exactly('expr long LocalVariable = 0; LocalVaria',
+                              'expr long LocalVariable = 0; LocalVariable')
+
+        # Custom Decls
+        self.complete_exactly('expr auto l = [](int LeftHandSide, int bx){ return LeftHandS',
+                              'expr auto l = [](int LeftHandSide, int bx){ return LeftHandSide')
+        self.complete_exactly('expr struct LocalStruct { long MemberName; } ; LocalStruct S; S.Mem',
+                              'expr struct LocalStruct { long MemberName; } ; LocalStruct S; S.MemberName')
+
+        # Completing function call arguments
+        self.complete_exactly('expr some_expr.FooWithArgsBar(some_exp',
+                              'expr some_expr.FooWithArgsBar(some_expr')
+        self.complete_exactly('expr some_expr.FooWithArgsBar(SomeIntV',
+                              'expr some_expr.FooWithArgsBar(SomeIntVar')
+        self.complete_exactly('expr some_expr.FooWithMultipleArgsBar(SomeIntVar, SomeIntVa',
+                              'expr some_expr.FooWithMultipleArgsBar(SomeIntVar, SomeIntVar')
+
+        # Function return values
+        self.complete_exactly('expr some_expr.Self().FooNoArgs',
+                              'expr some_expr.Self().FooNoArgsBar()')
+        self.complete_exactly('expr some_expr.Self() .FooNoArgs',
+                              'expr some_expr.Self() .FooNoArgsBar()')
+        self.complete_exactly('expr some_expr.Self(). FooNoArgs',
+                              'expr some_expr.Self(). FooNoArgsBar()')
+
+    def assume_no_completions(self, str_input, cursor_pos = None):
+        interp = self.dbg.GetCommandInterpreter()
+        match_strings = lldb.SBStringList()
+        if cursor_pos is None:
+          cursor_pos = len(str_input)
+        num_matches = interp.HandleCompletion(str_input, cursor_pos, 0, -1, match_strings)
+
+        available_completions = []
+        for m in match_strings:
+            available_completions.append(m)
+
+        self.assertEquals(num_matches, 0, "Got matches, but didn't expect any: " + str(available_completions))
+
+    def completions_contain(self, str_input, items):
+        interp = self.dbg.GetCommandInterpreter()
+        match_strings = lldb.SBStringList()
+        num_matches = interp.HandleCompletion(str_input, len(str_input), 0, -1, match_strings)
+        common_match = match_strings.GetStringAtIndex(0)
+
+        for item in items:
+            found = False
+            for m in match_strings:
+                if m == item:
+                    found = True
+            if not found:
+                # Transform match_strings to a python list with strings
+                available_completions = []
+                for m in match_strings:
+                     available_completions.append(m)
+                self.assertTrue(found, "Couldn't find completion " + item + " in completions " + str(available_completions))