Add offsetof support to expression evaluator.

Summary:
We currently don't support offsetof in the expression evaluator as it is implemented as a macro
(which then calls __builtin_offsetof) in stddef.h. The best solution would be to include that
header (or even better, import Clang's builtin module), but header-parsing and
(cross-platform) importing modules is not ready yet.

Until we get this working with modules I would say we add the macro to our existing macro list
as we already do with other macros from stddef.h/stdint.h. We should be able to drop all of them
once we can import the relevant modules by default.

rdar://26040641

Reviewers: shafik, davide

Reviewed By: davide

Subscribers: clayborg, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D64917

llvm-svn: 366476

3 files changed, 18 insertions, 0 deletions

diff --git a/lldb/packages/Python/lldbsuite/test/lang/c/offsetof/Makefile b/lldb/packages/Python/lldbsuite/test/lang/c/offsetof/Makefile
new file mode 100644
index 00000000000..cd9ca5c86d8
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/lang/c/offsetof/Makefile
@@ -0,0 +1,3 @@
+LEVEL = ../../../make
+C_SOURCES := main.c
+include $(LEVEL)/Makefile.rules
diff --git a/lldb/packages/Python/lldbsuite/test/lang/c/offsetof/TestOffsetof.py b/lldb/packages/Python/lldbsuite/test/lang/c/offsetof/TestOffsetof.py
new file mode 100644
index 00000000000..1311a149326
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/lang/c/offsetof/TestOffsetof.py
@@ -0,0 +1,3 @@
+from lldbsuite.test import lldbinline
+
+lldbinline.MakeInlineTest(__file__, globals())
diff --git a/lldb/packages/Python/lldbsuite/test/lang/c/offsetof/main.c b/lldb/packages/Python/lldbsuite/test/lang/c/offsetof/main.c
new file mode 100644
index 00000000000..cbb4a144418
--- /dev/null
+++ b/lldb/packages/Python/lldbsuite/test/lang/c/offsetof/main.c
@@ -0,0 +1,12 @@
+#include <stdint.h>
+
+struct Foo {
+  int8_t a;
+  int16_t b;
+};
+
+int main (int argc, char const *argv[]) {
+    struct Foo f;
+    return f.a; //% self.expect("expr offsetof(Foo, a)", substrs = ['= 0'])
+                //% self.expect("expr offsetof(Foo, b)", substrs = ['= 2'])
+}