226 lines
8.2 KiB
Diff
226 lines
8.2 KiB
Diff
From e7fbaebc8ff650df76f43e92cb9ca59d5174ebe7 Mon Sep 17 00:00:00 2001
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From: hjl <hjl@138bc75d-0d04-0410-961f-82ee72b054a4>
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Date: Thu, 15 Mar 2018 17:54:40 +0000
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Subject: [PATCH 13/13] i386: Don't generate alias for function return thunk
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Function return thunks shouldn't be aliased to indirect branch thunks
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since indirect branch thunks are placed in COMDAT section and a COMDAT
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section with indirect branch may not have function return thunk. This
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patch generates function return thunks directly.
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gcc/
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Backport from mainline
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PR target/84574
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* config/i386/i386.c (indirect_thunk_needed): Update comments.
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(indirect_thunk_bnd_needed): Likewise.
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(indirect_thunks_used): Likewise.
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(indirect_thunks_bnd_used): Likewise.
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(indirect_return_needed): New.
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(indirect_return_bnd_needed): Likewise.
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(output_indirect_thunk_function): Add a bool argument for
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function return.
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(output_indirect_thunk_function): Don't generate alias for
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function return thunk.
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(ix86_code_end): Call output_indirect_thunk_function to generate
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function return thunks.
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(ix86_output_function_return): Set indirect_return_bnd_needed
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and indirect_return_needed instead of indirect_thunk_bnd_needed
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and indirect_thunk_needed.
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gcc/testsuite/
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Backport from mainline
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PR target/84574
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* gcc.target/i386/ret-thunk-9.c: Expect __x86_return_thunk
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label instead of __x86_indirect_thunk label.
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---
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gcc/config/i386/i386.c | 92 ++++++++++-------------------
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gcc/testsuite/gcc.target/i386/ret-thunk-9.c | 2 +-
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2 files changed, 33 insertions(+), 61 deletions(-)
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diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
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index 21c3c18bd3c..f4cd1c6f4e9 100644
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--- a/gcc/config/i386/i386.c
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+++ b/gcc/config/i386/i386.c
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@@ -11067,19 +11067,23 @@ ix86_setup_frame_addresses (void)
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labels in call and return thunks. */
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static int indirectlabelno;
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-/* True if call and return thunk functions are needed. */
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+/* True if call thunk function is needed. */
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static bool indirect_thunk_needed = false;
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-/* True if call and return thunk functions with the BND prefix are
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- needed. */
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+/* True if call thunk function with the BND prefix is needed. */
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static bool indirect_thunk_bnd_needed = false;
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/* Bit masks of integer registers, which contain branch target, used
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- by call and return thunks functions. */
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+ by call thunk functions. */
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static int indirect_thunks_used;
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/* Bit masks of integer registers, which contain branch target, used
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- by call and return thunks functions with the BND prefix. */
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+ by call thunk functions with the BND prefix. */
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static int indirect_thunks_bnd_used;
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+/* True if return thunk function is needed. */
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+static bool indirect_return_needed = false;
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+/* True if return thunk function with the BND prefix is needed. */
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+static bool indirect_return_bnd_needed = false;
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+
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/* True if return thunk function via CX is needed. */
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static bool indirect_return_via_cx;
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/* True if return thunk function via CX with the BND prefix is
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@@ -11226,16 +11230,18 @@ output_indirect_thunk (bool need_bnd_p, unsigned int regno)
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/* Output a funtion with a call and return thunk for indirect branch.
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If BND_P is true, the BND prefix is needed. If REGNO != INVALID_REGNUM,
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the function address is in REGNO. Otherwise, the function address is
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- on the top of stack. */
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+ on the top of stack. Thunk is used for function return if RET_P is
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+ true. */
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static void
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-output_indirect_thunk_function (bool need_bnd_p, unsigned int regno)
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+output_indirect_thunk_function (bool need_bnd_p, unsigned int regno,
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+ bool ret_p)
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{
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char name[32];
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tree decl;
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/* Create __x86_indirect_thunk/__x86_indirect_thunk_bnd. */
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- indirect_thunk_name (name, regno, need_bnd_p, false);
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+ indirect_thunk_name (name, regno, need_bnd_p, ret_p);
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decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL,
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get_identifier (name),
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build_function_type_list (void_type_node, NULL_TREE));
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@@ -11278,50 +11284,6 @@ output_indirect_thunk_function (bool need_bnd_p, unsigned int regno)
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ASM_OUTPUT_LABEL (asm_out_file, name);
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}
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- /* Create alias for __x86_return_thunk/__x86_return_thunk_bnd or
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- __x86_return_thunk_ecx/__x86_return_thunk_ecx_bnd. */
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- bool need_alias;
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- if (regno == INVALID_REGNUM)
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- need_alias = true;
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- else if (regno == CX_REG)
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- {
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- if (need_bnd_p)
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- need_alias = indirect_return_via_cx_bnd;
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- else
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- need_alias = indirect_return_via_cx;
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- }
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- else
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- need_alias = false;
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-
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- if (need_alias)
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- {
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- char alias[32];
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-
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- indirect_thunk_name (alias, regno, need_bnd_p, true);
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-#if TARGET_MACHO
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- if (TARGET_MACHO)
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- {
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- fputs ("\t.weak_definition\t", asm_out_file);
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- assemble_name (asm_out_file, alias);
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- fputs ("\n\t.private_extern\t", asm_out_file);
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- assemble_name (asm_out_file, alias);
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- putc ('\n', asm_out_file);
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- ASM_OUTPUT_LABEL (asm_out_file, alias);
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- }
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-#else
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- ASM_OUTPUT_DEF (asm_out_file, alias, name);
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- if (USE_HIDDEN_LINKONCE)
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- {
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- fputs ("\t.globl\t", asm_out_file);
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- assemble_name (asm_out_file, alias);
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- putc ('\n', asm_out_file);
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- fputs ("\t.hidden\t", asm_out_file);
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- assemble_name (asm_out_file, alias);
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- putc ('\n', asm_out_file);
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- }
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-#endif
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- }
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-
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DECL_INITIAL (decl) = make_node (BLOCK);
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current_function_decl = decl;
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allocate_struct_function (decl, false);
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@@ -11368,19 +11330,29 @@ ix86_code_end (void)
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rtx xops[2];
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unsigned int regno;
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+ if (indirect_return_needed)
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+ output_indirect_thunk_function (false, INVALID_REGNUM, true);
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+ if (indirect_return_bnd_needed)
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+ output_indirect_thunk_function (true, INVALID_REGNUM, true);
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+
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+ if (indirect_return_via_cx)
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+ output_indirect_thunk_function (false, CX_REG, true);
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+ if (indirect_return_via_cx_bnd)
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+ output_indirect_thunk_function (true, CX_REG, true);
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+
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if (indirect_thunk_needed)
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- output_indirect_thunk_function (false, INVALID_REGNUM);
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+ output_indirect_thunk_function (false, INVALID_REGNUM, false);
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if (indirect_thunk_bnd_needed)
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- output_indirect_thunk_function (true, INVALID_REGNUM);
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+ output_indirect_thunk_function (true, INVALID_REGNUM, false);
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for (regno = FIRST_REX_INT_REG; regno <= LAST_REX_INT_REG; regno++)
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{
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unsigned int i = regno - FIRST_REX_INT_REG + LAST_INT_REG + 1;
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if ((indirect_thunks_used & (1 << i)))
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- output_indirect_thunk_function (false, regno);
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+ output_indirect_thunk_function (false, regno, false);
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if ((indirect_thunks_bnd_used & (1 << i)))
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- output_indirect_thunk_function (true, regno);
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+ output_indirect_thunk_function (true, regno, false);
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}
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for (regno = AX_REG; regno <= SP_REG; regno++)
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@@ -11389,10 +11361,10 @@ ix86_code_end (void)
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tree decl;
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if ((indirect_thunks_used & (1 << regno)))
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- output_indirect_thunk_function (false, regno);
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+ output_indirect_thunk_function (false, regno, false);
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if ((indirect_thunks_bnd_used & (1 << regno)))
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- output_indirect_thunk_function (true, regno);
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+ output_indirect_thunk_function (true, regno, false);
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if (!(pic_labels_used & (1 << regno)))
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continue;
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@@ -28077,12 +28049,12 @@ ix86_output_function_return (bool long_p)
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true);
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if (need_bnd_p)
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{
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- indirect_thunk_bnd_needed |= need_thunk;
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+ indirect_return_bnd_needed |= need_thunk;
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fprintf (asm_out_file, "\tbnd jmp\t%s\n", thunk_name);
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}
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else
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{
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- indirect_thunk_needed |= need_thunk;
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+ indirect_return_needed |= need_thunk;
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fprintf (asm_out_file, "\tjmp\t%s\n", thunk_name);
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}
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}
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diff --git a/gcc/testsuite/gcc.target/i386/ret-thunk-9.c b/gcc/testsuite/gcc.target/i386/ret-thunk-9.c
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index d2df8b874e0..eee230ca2f6 100644
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--- a/gcc/testsuite/gcc.target/i386/ret-thunk-9.c
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+++ b/gcc/testsuite/gcc.target/i386/ret-thunk-9.c
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@@ -13,7 +13,7 @@ foo (void)
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/* { dg-final { scan-assembler "jmp\[ \t\]*__x86_return_thunk" } } */
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/* { dg-final { scan-assembler "jmp\[ \t\]*\.LIND" } } */
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/* { dg-final { scan-assembler "call\[ \t\]*\.LIND" } } */
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-/* { dg-final { scan-assembler "__x86_indirect_thunk:" } } */
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+/* { dg-final { scan-assembler "__x86_return_thunk:" } } */
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/* { dg-final { scan-assembler "mov(?:l|q)\[ \t\]*_?bar" { target *-*-linux* } } } */
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/* { dg-final { scan-assembler-times {\tpause} 2 } } */
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/* { dg-final { scan-assembler-times {\tlfence} 2 } } */
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--
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2.16.3
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