lib: Make libunwind optional again

Apparently it's really not great to require it for a bunch of
platforms. Requested by Sean and Eric.

v2: Use combo option (Petri).

v3: Fix the right option (Petri)

v4: try a bit harder ...

v5: Even more simplification (Dylan)

Cc: Dylan Baker <dylan@pnwbakers.com>
Cc: Petri Latvala <petri.latvala@intel.com>
Reviewed-by: Eric Anholt <eric@anholt.net> (v1)
Reviewed-by: Petri Latvala <petri.latvala@intel.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

1 files changed, 46 insertions, 0 deletions

diff --git a/lib/stubs/libunwind/libunwind.h b/lib/stubs/libunwind/libunwind.h
new file mode 100644
index 00000000..ce5f30df
--- /dev/null
+++ b/lib/stubs/libunwind/libunwind.h
@@ -0,0 +1,46 @@
+/*
+ * Copyright © 2018 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Daniel Vetter <daniel.vetter@ffwll.ch>
+ */
+
+/* dummy libunwind header with stubs, only the minimal amount we need to get by */
+
+
+typedef int unw_cursor_t;
+typedef int unw_context_t;
+typedef int unw_word_t;
+
+#define UNW_REG_IP 0
+
+static inline void unw_getcontext(unw_context_t *uc) {}
+static inline void unw_init_local(unw_cursor_t *cursor, unw_context_t *uc) {}
+static inline int unw_step(unw_cursor_t *cursor) { return 0; }
+static inline int unw_get_reg (unw_cursor_t *cursor, int i, unw_word_t * word)
+{
+	return 0;
+}
+static inline int unw_get_proc_name (unw_cursor_t *cursor, char *c, size_t s, unw_word_t *word)
+{
+	return 0;
+}