When checking the address of a weak symbol in an executable, it is mandatory to use the GOTFUNCDESC scheme so that the address==NULL semantic is valid if the symbol is not present in the final link.
2018-XX-XX Christophe Lyon <christophe.l...@st.com> Mickaël Guêné <mickael.gu...@st.com> gcc/ * config/arm/arm.c (arm_local_funcdesc_p): New function. (legitimize_pic_address): Handle weak symbols in FDPIC mode. (arm_assemble_integer): Likewise. Change-Id: I3fa0b63bc0f672903f405aa72cc46052de1c0feb diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c index bbf8884..025485d 100644 --- a/gcc/config/arm/arm.c +++ b/gcc/config/arm/arm.c @@ -3771,6 +3771,46 @@ arm_options_perform_arch_sanity_checks (void) } } +/* Test whether a local function descriptor is canonical, i.e., + whether we can use GOTOFFFUNCDESC to compute the address of the + function. */ +static bool +arm_local_funcdesc_p (rtx fnx) +{ + tree fn; + enum symbol_visibility vis; + bool ret; + + if (!TARGET_FDPIC) + return TRUE; + + if (! SYMBOL_REF_LOCAL_P (fnx)) + return FALSE; + + fn = SYMBOL_REF_DECL (fnx); + + if (! fn) + return FALSE; + + /* Local function declared as weak must use GOTFUNCDESC so their + FUNCDESC is NULL if they are not linked in. */ + if (DECL_WEAK(fn)) + return FALSE; + + vis = DECL_VISIBILITY (fn); + + if (vis == VISIBILITY_PROTECTED) + /* Private function descriptors for protected functions are not + canonical. Temporarily change the visibility to global. */ + vis = VISIBILITY_DEFAULT; + + ret = default_binds_local_p_1 (fn, flag_pic); + + DECL_VISIBILITY (fn) = vis; + + return ret; +} + static void arm_add_gc_roots (void) { @@ -7488,7 +7528,9 @@ legitimize_pic_address (rtx orig, machine_mode mode, rtx reg) || (GET_CODE (orig) == SYMBOL_REF && SYMBOL_REF_LOCAL_P (orig) && (SYMBOL_REF_DECL (orig) - ? !DECL_WEAK (SYMBOL_REF_DECL (orig)) : 1))) + ? !DECL_WEAK (SYMBOL_REF_DECL (orig)) : 1) + && (!SYMBOL_REF_FUNCTION_P(orig) + || arm_local_funcdesc_p (orig)))) && NEED_GOT_RELOC && arm_pic_data_is_text_relative) insn = arm_pic_static_addr (orig, reg); @@ -23072,7 +23114,9 @@ arm_assemble_integer (rtx x, unsigned int size, int aligned_p) || (GET_CODE (x) == SYMBOL_REF && (!SYMBOL_REF_LOCAL_P (x) || (SYMBOL_REF_DECL (x) - ? DECL_WEAK (SYMBOL_REF_DECL (x)) : 0)))) + ? DECL_WEAK (SYMBOL_REF_DECL (x)) : 0) + || (SYMBOL_REF_FUNCTION_P (x) + && !arm_local_funcdesc_p (x))))) { if (TARGET_FDPIC && SYMBOL_REF_FUNCTION_P (x)) fputs ("(GOTFUNCDESC)", asm_out_file); -- 2.6.3