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Commit 3d3e1cf2 authored by Vishwath Mohan's avatar Vishwath Mohan
Browse files

CFI compatibility with static executables and nested archives 

This CL makes the following changes:
(a) It disables diagnostics for CFI which requires the runtime ubsan
library (which isn't included in static executables).

(b) It applies the ar flags for CFI correctly for nested .a
archives.

(c) Applies the version script to export CFI shadow for non-static
binaries

(d) Doesn't apply cross-dso CFI for static executables

Bug: 30227045
Test: Static executables build correctly and do not complain about
missing symbols from the ubsan runtime library.
Test: Nested .a files correctly use the gold plugin.

Change-Id: Id8fe3c13f6b76565aafbf1266e95f50d1447a790
parent 5dd30575

core/config_sanitizers.mk

+25 −6
Original line number Diff line number Diff line
@@ -235,6 +235,11 @@ ifneq ($(filter cfi,$(my_sanitize)),) 
  # entire module.

  LOCAL_ARM_MODE := thumb

  my_cflags += $(CFI_EXTRA_CFLAGS)

  # Only append the default visibility flag if -fvisibility has not already been

  # set to hidden.

  ifeq ($(filter -fvisibility=hidden,$(LOCAL_CFLAGS)),)

    my_cflags += -fvisibility=default

  endif

  my_ldflags += $(CFI_EXTRA_LDFLAGS)

  my_arflags += --plugin $(LLVM_PREBUILTS_PATH)/../lib64/LLVMgold.so

  # Workaround for b/33678192. CFI jumptables need Thumb2 codegen.  Revert when
@@ -242,6 +247,15 @@ ifneq ($(filter cfi,$(my_sanitize)),) 
  ifneq ($(filter arm,$(TARGET_$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)),)

    my_ldflags += -march=armv7-a

  endif



  ifeq ($(LOCAL_FORCE_STATIC_EXECUTABLE),true)

        my_ldflags := $(filter-out -fsanitize-cfi-cross-dso,$(my_ldflags))

        my_cflags := $(filter-out -fsanitize-cfi-cross-dso,$(my_cflags))

  else

        # Apply the version script to non-static executables

        my_ldflags += -Wl,--version-script,build/soong/cc/config/cfi_exports.map

        LOCAL_ADDITIONAL_DEPENDENCIES += build/soong/cc/config/cfi_exports.map

  endif

endif



# If local or global modules need ASAN, add linker flags.
@@ -293,6 +307,10 @@ ifneq ($(strip $(LOCAL_SANITIZE_RECOVER)),) 
endif



ifneq ($(my_sanitize_diag),)

  # TODO(vishwath): Add diagnostic support for static executables once

  # we switch to clang-4393122 (which adds the static ubsan runtime

  # that this depends on)

  ifneq ($(LOCAL_FORCE_STATIC_EXECUTABLE),true)

    notrap_arg := $(subst $(space),$(comma),$(my_sanitize_diag)),

    my_cflags += -fno-sanitize-trap=$(notrap_arg)

    # Diagnostic requires a runtime library, unless ASan or TSan are also enabled.
@@ -301,3 +319,4 @@ ifneq ($(my_sanitize_diag),) 
      my_shared_libraries += $($(LOCAL_2ND_ARCH_VAR_PREFIX)UBSAN_RUNTIME_LIBRARY)

    endif

  endif

endif

core/definitions.mk

+1 −1
Original line number Diff line number Diff line
@@ -1556,7 +1556,7 @@ $(hide) ldir=$(PRIVATE_INTERMEDIATES_DIR)/WHOLE/$(basename $(notdir $(1)))_objs; 
        filelist="$$filelist $$ldir/$$ext$$f"; \

    done ; \

    $($(PRIVATE_2ND_ARCH_VAR_PREFIX)TARGET_AR) $($(PRIVATE_2ND_ARCH_VAR_PREFIX)TARGET_GLOBAL_ARFLAGS) \

        $(2) $$filelist

        $(PRIVATE_ARFLAGS) $(2) $$filelist



endef