[Lldb-commits] [PATCH] D50481: Fix broken builtin functions in the expression command

[Raphael Isemann via Phabricator via lldb-commits]

teemperor created this revision.

Calling any non-libc builtin function in the expression command currently just causes Clang
to state that the function is not known. The reason for this is that we actually never
initialize the list of builtin functions in the Builtin::Context.

This patch just calls the initializer for the builtins in the preprocessor. Also adds some tests
for the new builtins.

It also gets rid of the extra list of builtins in the ClangExpressionParser, as we can just reuse
the existing list in the Preprocessor for the ASTContext. Having just one list of builtins around
is also closer to the standard Clang behavior.


Repository:
  rLLDB LLDB

https://reviews.llvm.org/D50481

Files:
  packages/Python/lldbsuite/test/expression_command/call-function/TestCallBuiltinFunction.py
  source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
  source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h


Index: source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
===================================================================
--- source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
+++ source/Plugins/ExpressionParser/Clang/ClangExpressionParser.h
@@ -149,8 +149,6 @@
       m_file_manager; ///< The Clang file manager object used by the compiler
   std::unique_ptr<clang::CompilerInstance>
       m_compiler; ///< The Clang compiler used to parse expressions into IR
-  std::unique_ptr<clang::Builtin::Context>
-      m_builtin_context; ///< Context for Clang built-ins
   std::unique_ptr<clang::SelectorTable>
       m_selector_table; ///< Selector table for Objective-C methods
   std::unique_ptr<clang::CodeGenerator>
Index: source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
===================================================================
--- source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
+++ source/Plugins/ExpressionParser/Clang/ClangExpressionParser.cpp
@@ -508,12 +508,21 @@
   // 8. Most of this we get from the CompilerInstance, but we also want to give
   // the context an ExternalASTSource.
   m_selector_table.reset(new SelectorTable());
-  m_builtin_context.reset(new Builtin::Context());
+
+  // We enable all builtin functions beside the builtins from libc/libm (e.g.
+  // 'fopen'). Those libc functions are already correctly handled by LLDB, and
+  // additionally enabling them as expandable builtins is breaking Clang.
+  m_compiler->getLangOpts().NoBuiltin = true;
+
+  auto &PP = m_compiler->getPreprocessor();
+  PP.getBuiltinInfo().initializeBuiltins(PP.getIdentifierTable(),
+                                         m_compiler->getLangOpts());
+  auto &builtin_context = PP.getBuiltinInfo();
 
   std::unique_ptr<clang::ASTContext> ast_context(
       new ASTContext(m_compiler->getLangOpts(), m_compiler->getSourceManager(),
                      m_compiler->getPreprocessor().getIdentifierTable(),
-                     *m_selector_table.get(), *m_builtin_context.get()));
+                     *m_selector_table.get(), builtin_context));
 
   ast_context->InitBuiltinTypes(m_compiler->getTarget());
 
Index: packages/Python/lldbsuite/test/expression_command/call-function/TestCallBuiltinFunction.py
===================================================================
--- /dev/null
+++ packages/Python/lldbsuite/test/expression_command/call-function/TestCallBuiltinFunction.py
@@ -0,0 +1,41 @@
+"""
+Test calling builtin functions using expression evaluation.
+
+"""
+
+from __future__ import print_function
+
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class ExprCommandCallBuiltinFunction(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    def setUp(self):
+        TestBase.setUp(self)
+        # Find the line number to break for main.c.
+        self.line = line_number(
+            'main.cpp',
+            '// Please test these expressions while stopped at this line:')
+
+    def test(self):
+        """Test return values of user defined function calls."""
+        self.build()
+
+        # Set breakpoint in main and run exe
+        self.runCmd("file " + self.getBuildArtifact("a.out"), CURRENT_EXECUTABLE_SET)
+        lldbutil.run_break_set_by_file_and_line(
+            self, "main.cpp", self.line, num_expected_locations=-1, loc_exact=True)
+
+        self.runCmd("run", RUN_SUCCEEDED)
+
+        # Test different builtin functions.
+        self.expect("expr __builtin_isinf(0.0f)", substrs=['(int) $0 = 0'])
+        self.expect("expr __builtin_isnormal(0.0f)", substrs=['(int) $1 = 0'])
+        self.expect("expr __builtin_constant_p(1)", substrs=['(int) $2 = 1'])
+        self.expect("expr __builtin_abs(-14)", substrs=['(int) $3 = 14'])


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