diff options
Diffstat (limited to 'community/gcc6/0013-i386-Don-t-generate-alias-for-function-return-thunk.patch')
| -rw-r--r-- | community/gcc6/0013-i386-Don-t-generate-alias-for-function-return-thunk.patch | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/community/gcc6/0013-i386-Don-t-generate-alias-for-function-return-thunk.patch b/community/gcc6/0013-i386-Don-t-generate-alias-for-function-return-thunk.patch new file mode 100644 index 0000000000..d846ac77d9 --- /dev/null +++ b/community/gcc6/0013-i386-Don-t-generate-alias-for-function-return-thunk.patch @@ -0,0 +1,225 @@ +From e7fbaebc8ff650df76f43e92cb9ca59d5174ebe7 Mon Sep 17 00:00:00 2001 +From: hjl <hjl@138bc75d-0d04-0410-961f-82ee72b054a4> +Date: Thu, 15 Mar 2018 17:54:40 +0000 +Subject: [PATCH 13/13] 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/ + + Backport from mainline + 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/ + + Backport from mainline + PR target/84574 + * gcc.target/i386/ret-thunk-9.c: Expect __x86_return_thunk + label instead of __x86_indirect_thunk label. +--- + gcc/config/i386/i386.c | 92 ++++++++++------------------- + gcc/testsuite/gcc.target/i386/ret-thunk-9.c | 2 +- + 2 files changed, 33 insertions(+), 61 deletions(-) + +diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c +index 21c3c18bd3c..f4cd1c6f4e9 100644 +--- a/gcc/config/i386/i386.c ++++ b/gcc/config/i386/i386.c +@@ -11067,19 +11067,23 @@ 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 +@@ -11226,16 +11230,18 @@ output_indirect_thunk (bool need_bnd_p, unsigned int regno) + /* Output a funtion with a call and return thunk for indirect branch. + If BND_P is true, the BND prefix is needed. If REGNO != INVALID_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 (bool need_bnd_p, unsigned int regno) ++output_indirect_thunk_function (bool need_bnd_p, 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_bnd_p, false); ++ indirect_thunk_name (name, regno, need_bnd_p, ret_p); + decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL, + get_identifier (name), + build_function_type_list (void_type_node, NULL_TREE)); +@@ -11278,50 +11284,6 @@ output_indirect_thunk_function (bool need_bnd_p, unsigned int regno) + 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_bnd_p) +- 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_bnd_p, 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); +@@ -11368,19 +11330,29 @@ ix86_code_end (void) + rtx xops[2]; + unsigned int regno; + ++ if (indirect_return_needed) ++ output_indirect_thunk_function (false, INVALID_REGNUM, true); ++ if (indirect_return_bnd_needed) ++ output_indirect_thunk_function (true, INVALID_REGNUM, true); ++ ++ if (indirect_return_via_cx) ++ output_indirect_thunk_function (false, CX_REG, true); ++ if (indirect_return_via_cx_bnd) ++ output_indirect_thunk_function (true, CX_REG, true); ++ + if (indirect_thunk_needed) +- output_indirect_thunk_function (false, INVALID_REGNUM); ++ output_indirect_thunk_function (false, INVALID_REGNUM, false); + if (indirect_thunk_bnd_needed) +- output_indirect_thunk_function (true, INVALID_REGNUM); ++ output_indirect_thunk_function (true, 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 (false, regno); ++ output_indirect_thunk_function (false, regno, false); + + if ((indirect_thunks_bnd_used & (1 << i))) +- output_indirect_thunk_function (true, regno); ++ output_indirect_thunk_function (true, regno, false); + } + + for (regno = AX_REG; regno <= SP_REG; regno++) +@@ -11389,10 +11361,10 @@ ix86_code_end (void) + tree decl; + + if ((indirect_thunks_used & (1 << regno))) +- output_indirect_thunk_function (false, regno); ++ output_indirect_thunk_function (false, regno, false); + + if ((indirect_thunks_bnd_used & (1 << regno))) +- output_indirect_thunk_function (true, regno); ++ output_indirect_thunk_function (true, regno, false); + + if (!(pic_labels_used & (1 << regno))) + continue; +@@ -28077,12 +28049,12 @@ ix86_output_function_return (bool long_p) + true); + if (need_bnd_p) + { +- 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); + } + } +diff --git a/gcc/testsuite/gcc.target/i386/ret-thunk-9.c b/gcc/testsuite/gcc.target/i386/ret-thunk-9.c +index d2df8b874e0..eee230ca2f6 100644 +--- a/gcc/testsuite/gcc.target/i386/ret-thunk-9.c ++++ b/gcc/testsuite/gcc.target/i386/ret-thunk-9.c +@@ -13,7 +13,7 @@ foo (void) + /* { dg-final { scan-assembler "jmp\[ \t\]*__x86_return_thunk" } } */ + /* { dg-final { scan-assembler "jmp\[ \t\]*\.LIND" } } */ + /* { dg-final { scan-assembler "call\[ \t\]*\.LIND" } } */ +-/* { dg-final { scan-assembler "__x86_indirect_thunk:" } } */ ++/* { dg-final { scan-assembler "__x86_return_thunk:" } } */ + /* { dg-final { scan-assembler "mov(?:l|q)\[ \t\]*_?bar" { target *-*-linux* } } } */ + /* { dg-final { scan-assembler-times {\tpause} 2 } } */ + /* { dg-final { scan-assembler-times {\tlfence} 2 } } */ +-- +2.16.3 + |