Makefile: Enable linker garbage collection

This patch enables -ffunction-sections, -fdata-sections and
-Wl,--gc-sections for host builds. These flags already get passed by
firmware builds anyway, so having host builds match that behavior should
be a good idea in general. They may also occasionally help save a bit of
code size (though not much since vboot is a library, but I still get
about half a KB out of futility), and they will prevent clang from
omitting relocations for function calls inside the same file, which
means we don't have to splatter test_mockable all over our codebase
anymore. (We still need it for vb2_get_gbb() since that is so small that
both GCC and clang want to inline it, even if they are outputting a
discrete copy anyway.)

(Also add a comment about why GenerateGuid() has nothing do to with this
even though it is also a weak function, and why it is like that.)

BRANCH=None
BUG=chromium:991812
TEST=make runtests with both GCC and clang

Change-Id: Iede9d29e20b99b75a0c86bc7ecb907d2a0e5e3a1
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1754969
Legacy-Commit-Queue: Commit Bot <commit-bot@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

3 files changed, 1 insertions, 9 deletions

diff --git a/firmware/include/vboot_api.h b/firmware/include/vboot_api.h
index 01106c0e..7f00ddc6 100644
--- a/firmware/include/vboot_api.h
+++ b/firmware/include/vboot_api.h
@@ -34,13 +34,6 @@ extern "C" {
 struct vb2_context;
 typedef struct VbSharedDataHeader VbSharedDataHeader;
 
-/*
- * Define test_mockable for mocking functions.
- */
-#ifndef test_mockable
-#define test_mockable __attribute__((weak))
-#endif
-
 
 /*****************************************************************************/
 /* Main entry points from firmware into vboot_reference */
diff --git a/firmware/lib20/packed_key.c b/firmware/lib20/packed_key.c
index af888e6e..42c66223 100644
--- a/firmware/lib20/packed_key.c
+++ b/firmware/lib20/packed_key.c
@@ -10,7 +10,6 @@
 #include "2rsa.h"
 #include "vb2_common.h"
 
-test_mockable
 vb2_error_t vb2_unpack_key_buffer(struct vb2_public_key *key,
 				  const uint8_t *buf, uint32_t size)
 {
diff --git a/firmware/stub/vboot_api_stub_init.c b/firmware/stub/vboot_api_stub_init.c
index 8fbc31df..7dc4c01c 100644
--- a/firmware/stub/vboot_api_stub_init.c
+++ b/firmware/stub/vboot_api_stub_init.c
@@ -23,7 +23,7 @@ uint64_t VbExGetTimer(void)
 	return (uint64_t)tv.tv_sec * VB_USEC_PER_SEC + (uint64_t)tv.tv_usec;
 }
 
-vb2_error_t test_mockable VbExNvStorageRead(uint8_t *buf)
+vb2_error_t VbExNvStorageRead(uint8_t *buf)
 {
 	return VB2_SUCCESS;
 }