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[ARM/FDPIC v3 08/21] [ARM] FDPIC: Ensure local/global binding for function descriptors
- From: Christophe Lyon <christophe dot lyon at st dot com>
- To: <gcc-patches at gcc dot gnu dot org>
- Cc: <christophe dot lyon at linaro dot org>
- Date: Thu, 11 Oct 2018 15:34:45 +0200
- Subject: [ARM/FDPIC v3 08/21] [ARM] FDPIC: Ensure local/global binding for function descriptors
- References: <20181011133518.17258-1-christophe.lyon@st.com>
Use local binding rules to decide whether we can use GOTOFFFUNCDESC to
compute the function address.
2018-XX-XX Christophe Lyon <christophe.lyon@st.com>
Mickaël Guêné <mickael.guene@st.com>
gcc/
* config/arm/arm.c (arm_local_funcdesc_p): New function.
(legitimize_pic_address): Ensure binding rules on function
pointers 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 a6dce36..d0144fd 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -3768,6 +3768,42 @@ 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;
+
+ vis = DECL_VISIBILITY (fn);
+
+ if (vis == VISIBILITY_PROTECTED)
+ /* Private function descriptors for protected functions are not
+ canonical. Temporarily change the visibility to global so that
+ we can ensure unicity of funcdesc pointers. */
+ DECL_VISIBILITY (fn) = VISIBILITY_DEFAULT;
+
+ ret = default_binds_local_p_1 (fn, flag_pic);
+
+ DECL_VISIBILITY (fn) = vis;
+
+ return ret;
+}
+
static void
arm_add_gc_roots (void)
{
@@ -7485,7 +7521,9 @@ 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);
@@ -23053,7 +23091,9 @@ 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