From: <christophe.lyon@st.com>
To: <gcc-patches@gcc.gnu.org>
Cc: <christophe.lyon@linaro.org>
Subject: [ARM/FDPIC v2 09/21] [ARM] FDPIC: Add support for taking address of nested function
Date: Fri, 13 Jul 2018 16:15:00 -0000 [thread overview]
Message-ID: <20180713161136.29104-10-christophe.lyon@st.com> (raw)
In-Reply-To: <20180713161136.29104-1-christophe.lyon@st.com>
From: Christophe Lyon <christophe.lyon@linaro.org>
In FDPIC mode, the trampoline generated to support pointers to nested
functions looks like:
.word trampoline address
.word trampoline GOT address
ldr r12, [pc, #8]
ldr r9, [pc, #8]
ldr pc, [pc]
.word static chain value
.word GOT address
.word function's address
because in FDPIC function pointers are actually pointers to function
descriptors, we have to actually generate a function descriptor for
the trampoline.
2018-XX-XX Christophe Lyon <christophe.lyon@st.com>
Mickaël Guêné <mickael.guene@st.com>
gcc/
* config/arm/arm.c (arm_asm_trampoline_template): Add FDPIC
support.
(arm_trampoline_init): Likewise.
(arm_trampoline_init): Likewise.
* config/arm/arm.h (TRAMPOLINE_SIZE): Likewise.
Change-Id: I4b5127261a9aefa0f0318f110574ec07a856aeb1
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 51da2bc..ffc9128 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -3950,13 +3950,50 @@ arm_warn_func_return (tree decl)
.word static chain value
.word function's address
XXX FIXME: When the trampoline returns, r8 will be clobbered. */
+/* In FDPIC mode, the trampoline looks like:
+ .word trampoline address
+ .word trampoline GOT address
+ ldr r12, [pc, #8] ; #4 for Thumb2
+ ldr r9, [pc, #8] ; #4 for Thumb2
+ ldr pc, [pc, #8] ; #4 for Thumb2
+ .word static chain value
+ .word GOT address
+ .word function's address
+*/
static void
arm_asm_trampoline_template (FILE *f)
{
fprintf (f, "\t.syntax unified\n");
- if (TARGET_ARM)
+ if (TARGET_FDPIC)
+ {
+ /* The first two words are a function descriptor pointing to the
+ trampoline code just below. */
+ if (TARGET_ARM)
+ fprintf (f, "\t.arm\n");
+ else if (TARGET_THUMB2)
+ fprintf (f, "\t.thumb\n");
+ else
+ /* Only ARM and Thumb-2 are supported. */
+ gcc_assert ( !TARGET_ARM && !TARGET_THUMB2);
+
+ assemble_aligned_integer (UNITS_PER_WORD, const0_rtx);
+ assemble_aligned_integer (UNITS_PER_WORD, const0_rtx);
+ /* Trampoline code which sets the static chain register but also
+ PIC register before jumping into real code. */
+ asm_fprintf (f, "\tldr\t%r, [%r, #%d]\n",
+ STATIC_CHAIN_REGNUM, PC_REGNUM,
+ TARGET_THUMB2 ? 8 : 4);
+ asm_fprintf (f, "\tldr\t%r, [%r, #%d]\n",
+ PIC_OFFSET_TABLE_REGNUM, PC_REGNUM,
+ TARGET_THUMB2 ? 8 : 4);
+ asm_fprintf (f, "\tldr\t%r, [%r, #%d]\n",
+ PC_REGNUM, PC_REGNUM,
+ TARGET_THUMB2 ? 8 : 4);
+ assemble_aligned_integer (UNITS_PER_WORD, const0_rtx);
+ }
+ else if (TARGET_ARM)
{
fprintf (f, "\t.arm\n");
asm_fprintf (f, "\tldr\t%r, [%r, #0]\n", STATIC_CHAIN_REGNUM, PC_REGNUM);
@@ -3997,12 +4034,37 @@ arm_trampoline_init (rtx m_tramp, tree fndecl, rtx chain_value)
emit_block_move (m_tramp, assemble_trampoline_template (),
GEN_INT (TRAMPOLINE_SIZE), BLOCK_OP_NORMAL);
- mem = adjust_address (m_tramp, SImode, TARGET_32BIT ? 8 : 12);
- emit_move_insn (mem, chain_value);
+ if (TARGET_FDPIC)
+ {
+ rtx funcdesc = XEXP (DECL_RTL (fndecl), 0);
+ rtx fnaddr = gen_rtx_MEM (Pmode, funcdesc);
+ rtx gotaddr = gen_rtx_MEM (Pmode, plus_constant (Pmode, funcdesc, 4));
+ rtx trampoline_code_start
+ = plus_constant (Pmode, XEXP (m_tramp, 0), TARGET_THUMB2 ? 9 : 8);
+
+ /* Write initial funcdesc which points to the trampoline. */
+ mem = adjust_address (m_tramp, SImode, 0);
+ emit_move_insn (mem, trampoline_code_start);
+ mem = adjust_address (m_tramp, SImode, 4);
+ emit_move_insn (mem, gen_rtx_REG (Pmode, PIC_OFFSET_TABLE_REGNUM));
+ /* Setup static chain. */
+ mem = adjust_address (m_tramp, SImode, 20);
+ emit_move_insn (mem, chain_value);
+ /* GOT + real function entry point. */
+ mem = adjust_address (m_tramp, SImode, 24);
+ emit_move_insn (mem, gotaddr);
+ mem = adjust_address (m_tramp, SImode, 28);
+ emit_move_insn (mem, fnaddr);
+ }
+ else
+ {
+ mem = adjust_address (m_tramp, SImode, TARGET_32BIT ? 8 : 12);
+ emit_move_insn (mem, chain_value);
- mem = adjust_address (m_tramp, SImode, TARGET_32BIT ? 12 : 16);
- fnaddr = XEXP (DECL_RTL (fndecl), 0);
- emit_move_insn (mem, fnaddr);
+ mem = adjust_address (m_tramp, SImode, TARGET_32BIT ? 12 : 16);
+ fnaddr = XEXP (DECL_RTL (fndecl), 0);
+ emit_move_insn (mem, fnaddr);
+ }
a_tramp = XEXP (m_tramp, 0);
emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__clear_cache"),
@@ -4016,7 +4078,9 @@ arm_trampoline_init (rtx m_tramp, tree fndecl, rtx chain_value)
static rtx
arm_trampoline_adjust_address (rtx addr)
{
- if (TARGET_THUMB)
+ /* For FDPIC don't fix trampoline address since it's a function
+ descriptor and not a function address. */
+ if (TARGET_THUMB && !TARGET_FDPIC)
addr = expand_simple_binop (Pmode, IOR, addr, const1_rtx,
NULL, 0, OPTAB_LIB_WIDEN);
return addr;
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 4671d64..22a65a1 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -1581,7 +1581,7 @@ typedef struct
#define INIT_EXPANDERS arm_init_expanders ()
/* Length in units of the trampoline for entering a nested function. */
-#define TRAMPOLINE_SIZE (TARGET_32BIT ? 16 : 20)
+#define TRAMPOLINE_SIZE (TARGET_FDPIC ? 32 : (TARGET_32BIT ? 16 : 20))
/* Alignment required for a trampoline in bits. */
#define TRAMPOLINE_ALIGNMENT 32
--
2.6.3
next prev parent reply other threads:[~2018-07-13 16:15 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-13 16:12 [ARM/FDPIC v2 00/21] FDPIC ABI for ARM christophe.lyon
2018-07-13 16:12 ` [ARM/FDPIC v2 02/21] [ARM] FDPIC: Handle arm*-*-uclinuxfdpiceabi in configure scripts christophe.lyon
2018-08-29 10:46 ` Kyrill Tkachov
2018-08-31 14:13 ` Christophe Lyon
2018-09-09 8:16 ` Christophe Lyon
2018-07-13 16:12 ` [ARM/FDPIC v2 01/21] [ARM] FDPIC: Add -mfdpic option support christophe.lyon
2018-08-29 10:46 ` Kyrill Tkachov
2018-08-31 14:09 ` Christophe Lyon
2018-09-21 15:41 ` Christophe Lyon
2018-07-13 16:13 ` [ARM/FDPIC v2 04/21] [ARM] FDPIC: Add support for FDPIC for arm architecture christophe.lyon
2018-08-29 10:46 ` Kyrill Tkachov
2018-09-04 15:29 ` Richard Earnshaw (lists)
2018-09-05 12:07 ` Christophe Lyon
2018-07-13 16:13 ` [ARM/FDPIC v2 03/21] [ARM] FDPIC: Force FDPIC related options unless -mno-fdpic is provided christophe.lyon
2018-07-13 16:13 ` [ARM/FDPIC v2 05/21] [ARM] FDPIC: Fix __do_global_dtors_aux and frame_dummy generation christophe.lyon
2018-07-13 16:14 ` [ARM/FDPIC v2 07/21] [ARM] FDPIC: Avoid saving/restoring r9 on stack since it is RO christophe.lyon
2018-08-29 10:52 ` Kyrill Tkachov
2018-07-13 16:14 ` [ARM/FDPIC v2 06/21] [ARM] FDPIC: Add support for c++ exceptions christophe.lyon
2018-08-29 10:49 ` Kyrill Tkachov
2018-07-13 16:14 ` [ARM/FDPIC v2 08/21] [ARM] FDPIC: Ensure local/global binding for function descriptors christophe.lyon
2018-07-13 16:15 ` [ARM/FDPIC v2 10/21] [ARM] FDPIC: Implement TLS support christophe.lyon
2018-07-13 16:15 ` [ARM/FDPIC v2 11/21] [ARM] FDPIC: Add support to unwind FDPIC signal frame christophe.lyon
2018-07-13 16:15 ` christophe.lyon [this message]
2018-08-29 11:01 ` [ARM/FDPIC v2 09/21] [ARM] FDPIC: Add support for taking address of nested function Kyrill Tkachov
2018-08-31 14:17 ` Christophe Lyon
2018-07-13 16:16 ` [ARM/FDPIC v2 12/21] [ARM] FDPIC: Restore r9 after we call __aeabi_read_tp christophe.lyon
2018-07-13 16:16 ` [ARM/FDPIC v2 13/21] [ARM] FDPIC: Force LSB bit for PC in Cortex-M architecture christophe.lyon
2018-07-13 16:16 ` [ARM/FDPIC v2 14/21] [ARM][testsuite] FDPIC: Skip unsupported tests christophe.lyon
2018-07-13 16:17 ` [ARM/FDPIC v2 15/21] [ARM][testsuite] FDPIC: Adjust scan-assembler patterns christophe.lyon
2018-07-13 16:17 ` [ARM/FDPIC v2 17/21] [ARM][testsuite] FDPIC: Skip tests that don't work in PIC mode christophe.lyon
2018-07-13 16:17 ` [ARM/FDPIC v2 16/21] [ARM][testsuite] FDPIC: Skip v8-m and v6-m tests that currently produce an ICE christophe.lyon
2018-07-13 16:18 ` [ARM/FDPIC v2 19/21] [ARM][testsuite] FDPIC: Enable tests on pie_enabled targets christophe.lyon
2018-07-13 16:18 ` [ARM/FDPIC v2 20/21] [ARM][testsuite] FDPIC: Adjust pr43698.c to avoid clash with uclibc christophe.lyon
2018-07-13 16:18 ` [ARM/FDPIC v2 18/21] [ARM][testsuite] FDPIC: Handle *-*-uclinux* christophe.lyon
2018-07-13 16:19 ` [ARM/FDPIC v2 21/21] [ARM][testsuite] FDPIC: Skip tests using architecture older than v7 christophe.lyon
2018-08-01 14:03 ` [ARM/FDPIC v2 00/21] FDPIC ABI for ARM Christophe Lyon
2018-08-16 22:20 ` Christophe Lyon
2018-08-28 16:09 ` Christophe Lyon
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