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author | H.J. Lu <hongjiu.lu@intel.com> | 2018-03-15 17:54:40 +0000 |
---|---|---|
committer | H.J. Lu <hjl@gcc.gnu.org> | 2018-03-15 10:54:40 -0700 |
commit | 23f95cb77ab469d83f9fcc35417a6c66f823cf92 (patch) | |
tree | a8229da1eb51aaa17f500762fbad39c6fb9611ac /gcc/config | |
parent | 4a5a49b034eed5373f6968c99bda1827f1479580 (diff) | |
download | gcc-23f95cb77ab469d83f9fcc35417a6c66f823cf92.zip gcc-23f95cb77ab469d83f9fcc35417a6c66f823cf92.tar.gz gcc-23f95cb77ab469d83f9fcc35417a6c66f823cf92.tar.bz2 |
i386: Don't generate alias for function return thunk
Function return thunks shouldn't be aliased to indirect branch thunks
since indirect branch thunks are placed in COMDAT section and a COMDAT
section with indirect branch may not have function return thunk. This
patch generates function return thunks directly.
gcc/
PR target/84574
* config/i386/i386.c (indirect_thunk_needed): Update comments.
(indirect_thunk_bnd_needed): Likewise.
(indirect_thunks_used): Likewise.
(indirect_thunks_bnd_used): Likewise.
(indirect_return_needed): New.
(indirect_return_bnd_needed): Likewise.
(output_indirect_thunk_function): Add a bool argument for
function return.
(output_indirect_thunk_function): Don't generate alias for
function return thunk.
(ix86_code_end): Call output_indirect_thunk_function to generate
function return thunks.
(ix86_output_function_return): Set indirect_return_bnd_needed
and indirect_return_needed instead of indirect_thunk_bnd_needed
and indirect_thunk_needed.
gcc/testsuite/
PR target/84574
* gcc.target/i386/ret-thunk-9.c: Expect __x86_return_thunk
label instead of __x86_indirect_thunk label.
From-SVN: r258569
Diffstat (limited to 'gcc/config')
-rw-r--r-- | gcc/config/i386/i386.c | 95 |
1 files changed, 35 insertions, 60 deletions
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 1b57cc6..00668b4 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -10819,19 +10819,23 @@ ix86_setup_frame_addresses (void) labels in call and return thunks. */ static int indirectlabelno; -/* True if call and return thunk functions are needed. */ +/* True if call thunk function is needed. */ static bool indirect_thunk_needed = false; -/* True if call and return thunk functions with the BND prefix are - needed. */ +/* True if call thunk function with the BND prefix is needed. */ static bool indirect_thunk_bnd_needed = false; /* Bit masks of integer registers, which contain branch target, used - by call and return thunks functions. */ + by call thunk functions. */ static int indirect_thunks_used; /* Bit masks of integer registers, which contain branch target, used - by call and return thunks functions with the BND prefix. */ + by call thunk functions with the BND prefix. */ static int indirect_thunks_bnd_used; +/* True if return thunk function is needed. */ +static bool indirect_return_needed = false; +/* True if return thunk function with the BND prefix is needed. */ +static bool indirect_return_bnd_needed = false; + /* True if return thunk function via CX is needed. */ static bool indirect_return_via_cx; /* True if return thunk function via CX with the BND prefix is @@ -11027,17 +11031,18 @@ output_indirect_thunk (enum indirect_thunk_prefix need_prefix, /* Output a funtion with a call and return thunk for indirect branch. If BND_P is true, the BND prefix is needed. If REGNO != UNVALID_REGNUM, the function address is in REGNO. Otherwise, the function address is - on the top of stack. */ + on the top of stack. Thunk is used for function return if RET_P is + true. */ static void output_indirect_thunk_function (enum indirect_thunk_prefix need_prefix, - unsigned int regno) + unsigned int regno, bool ret_p) { char name[32]; tree decl; /* Create __x86_indirect_thunk/__x86_indirect_thunk_bnd. */ - indirect_thunk_name (name, regno, need_prefix, false); + indirect_thunk_name (name, regno, need_prefix, ret_p); decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, get_identifier (name), build_function_type_list (void_type_node, NULL_TREE)); @@ -11080,50 +11085,6 @@ output_indirect_thunk_function (enum indirect_thunk_prefix need_prefix, ASM_OUTPUT_LABEL (asm_out_file, name); } - /* Create alias for __x86_return_thunk/__x86_return_thunk_bnd or - __x86_return_thunk_ecx/__x86_return_thunk_ecx_bnd. */ - bool need_alias; - if (regno == INVALID_REGNUM) - need_alias = true; - else if (regno == CX_REG) - { - if (need_prefix == indirect_thunk_prefix_bnd) - need_alias = indirect_return_via_cx_bnd; - else - need_alias = indirect_return_via_cx; - } - else - need_alias = false; - - if (need_alias) - { - char alias[32]; - - indirect_thunk_name (alias, regno, need_prefix, true); -#if TARGET_MACHO - if (TARGET_MACHO) - { - fputs ("\t.weak_definition\t", asm_out_file); - assemble_name (asm_out_file, alias); - fputs ("\n\t.private_extern\t", asm_out_file); - assemble_name (asm_out_file, alias); - putc ('\n', asm_out_file); - ASM_OUTPUT_LABEL (asm_out_file, alias); - } -#else - ASM_OUTPUT_DEF (asm_out_file, alias, name); - if (USE_HIDDEN_LINKONCE) - { - fputs ("\t.globl\t", asm_out_file); - assemble_name (asm_out_file, alias); - putc ('\n', asm_out_file); - fputs ("\t.hidden\t", asm_out_file); - assemble_name (asm_out_file, alias); - putc ('\n', asm_out_file); - } -#endif - } - DECL_INITIAL (decl) = make_node (BLOCK); current_function_decl = decl; allocate_struct_function (decl, false); @@ -11170,23 +11131,37 @@ ix86_code_end (void) rtx xops[2]; unsigned int regno; + if (indirect_return_needed) + output_indirect_thunk_function (indirect_thunk_prefix_none, + INVALID_REGNUM, true); + if (indirect_return_bnd_needed) + output_indirect_thunk_function (indirect_thunk_prefix_bnd, + INVALID_REGNUM, true); + + if (indirect_return_via_cx) + output_indirect_thunk_function (indirect_thunk_prefix_none, + CX_REG, true); + if (indirect_return_via_cx_bnd) + output_indirect_thunk_function (indirect_thunk_prefix_bnd, + CX_REG, true); + if (indirect_thunk_needed) output_indirect_thunk_function (indirect_thunk_prefix_none, - INVALID_REGNUM); + INVALID_REGNUM, false); if (indirect_thunk_bnd_needed) output_indirect_thunk_function (indirect_thunk_prefix_bnd, - INVALID_REGNUM); + INVALID_REGNUM, false); for (regno = FIRST_REX_INT_REG; regno <= LAST_REX_INT_REG; regno++) { unsigned int i = regno - FIRST_REX_INT_REG + LAST_INT_REG + 1; if ((indirect_thunks_used & (1 << i))) output_indirect_thunk_function (indirect_thunk_prefix_none, - regno); + regno, false); if ((indirect_thunks_bnd_used & (1 << i))) output_indirect_thunk_function (indirect_thunk_prefix_bnd, - regno); + regno, false); } for (regno = FIRST_INT_REG; regno <= LAST_INT_REG; regno++) @@ -11196,11 +11171,11 @@ ix86_code_end (void) if ((indirect_thunks_used & (1 << regno))) output_indirect_thunk_function (indirect_thunk_prefix_none, - regno); + regno, false); if ((indirect_thunks_bnd_used & (1 << regno))) output_indirect_thunk_function (indirect_thunk_prefix_bnd, - regno); + regno, false); if (!(pic_labels_used & (1 << regno))) continue; @@ -29060,12 +29035,12 @@ ix86_output_function_return (bool long_p) true); if (need_prefix == indirect_thunk_prefix_bnd) { - indirect_thunk_bnd_needed |= need_thunk; + indirect_return_bnd_needed |= need_thunk; fprintf (asm_out_file, "\tbnd jmp\t%s\n", thunk_name); } else { - indirect_thunk_needed |= need_thunk; + indirect_return_needed |= need_thunk; fprintf (asm_out_file, "\tjmp\t%s\n", thunk_name); } } |