From fab7995cd8cfe787a3ebc5620cce14cb59beda30 Mon Sep 17 00:00:00 2001
From: Yabin Cui <yabinc@google.com>
Date: Tue, 29 Mar 2016 12:22:20 -0700
Subject: [PATCH] Add strip mode mini-debug-info.

Mini-debug-info strip mode strips most debug information, but
maintains minimal debugging information similar to
https://sourceware.org/gdb/onlinedocs/gdb/MiniDebugInfo.html.

Bug: 27923447

Change-Id: I0405f0b3c33cb3cadeafbd22ce94d645c4dbe7b9
---
 core/definitions.mk    | 17 +++++++++++++++++
 core/dynamic_binary.mk |  7 ++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/core/definitions.mk b/core/definitions.mk
index 5a91045a1..15c9df05c 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1643,6 +1643,23 @@ $(hide) $(PRIVATE_STRIP) --strip-all $< -o $@ \
   $(if $(PRIVATE_NO_DEBUGLINK),,$(TARGET_STRIP_EXTRA))
 endef
 
+define transform-to-stripped-keep-mini-debug-info
+@echo "target Strip (mini debug info): $(PRIVATE_MODULE) ($@)"
+@mkdir -p $(dir $@)
+$(hide) $(PRIVATE_NM) -D $< --format=posix --defined-only | awk '{ print $$1 }' | sort >$@.dynsyms
+$(hide) $(PRIVATE_NM) $< --format=posix --defined-only | awk '{ if ($$2 == "T" || $$2 == "t" || $$2 == "D") print $$1 }' | sort >$@.funcsyms
+$(hide) comm -13 $@.dynsyms $@.funcsyms >$@.keep_symbols
+$(hide) $(PRIVATE_OBJCOPY) --only-keep-debug $< $@.debug
+$(hide) $(PRIVATE_OBJCOPY) --rename-section .debug_frame=saved_debug_frame $@.debug $@.mini_debuginfo
+$(hide) $(PRIVATE_OBJCOPY) -S --remove-section .gdb_index --remove-section .comment --keep-symbols=$@.keep_symbols $@.mini_debuginfo
+$(hide) $(PRIVATE_OBJCOPY) --rename-section saved_debug_frame=.debug_frame $@.mini_debuginfo
+$(hide) $(PRIVATE_STRIP) --strip-all -R .comment $< -o $@
+$(hide) rm -f $@.mini_debuginfo.xz
+$(hide) xz $@.mini_debuginfo
+$(hide) $(PRIVATE_OBJCOPY) --add-section .gnu_debugdata=$@.mini_debuginfo.xz $@
+$(hide) rm -f $@.dynsyms $@.funcsyms $@.keep_symbols $@.debug $@.mini_debuginfo.xz
+endef
+
 define transform-to-stripped-keep-symbols
 @echo "target Strip (keep symbols): $(PRIVATE_MODULE) ($@)"
 @mkdir -p $(dir $@)
diff --git a/core/dynamic_binary.mk b/core/dynamic_binary.mk
index 7ed5c35c8..f11803d35 100644
--- a/core/dynamic_binary.mk
+++ b/core/dynamic_binary.mk
@@ -121,6 +121,7 @@ endif
 
 $(strip_output): PRIVATE_STRIP := $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_STRIP)
 $(strip_output): PRIVATE_OBJCOPY := $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_OBJCOPY)
+$(strip_output): PRIVATE_NM := $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_NM)
 $(strip_output): PRIVATE_READELF := $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_READELF)
 ifeq ($(my_strip_module),no_debuglink)
 $(strip_output): PRIVATE_NO_DEBUGLINK := true
@@ -128,7 +129,11 @@ else
 $(strip_output): PRIVATE_NO_DEBUGLINK :=
 endif
 
-ifneq ($(filter true no_debuglink,$(my_strip_module)),)
+ifeq ($(my_strip_module),mini-debug-info)
+# Strip the binary, but keep debug frames and symbol table in a compressed .gnu_debugdata section.
+$(strip_output): $(strip_input) | $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_STRIP) $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_OBJCOPY) $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_NM)
+	$(transform-to-stripped-keep-mini-debug-info)
+else ifneq ($(filter true no_debuglink,$(my_strip_module)),)
 # Strip the binary
 $(strip_output): $(strip_input) | $($(LOCAL_2ND_ARCH_VAR_PREFIX)TARGET_STRIP)
 	$(transform-to-stripped)