From 5d46ec3db21d8c8926f15a634b2d6570536db5f1 Mon Sep 17 00:00:00 2001 From: Iain Sandoe Date: Mon, 16 Sep 2019 15:11:00 +0100 Subject: [PATCH] CFI-handling : Add a hook to allow target-specific Personality and LSDA indirections. At present, the output of .cfi_personality and .cfi_lsda assumes ELF semantics for indirections. This isn't suitable for all targets and is one blocker to moving Darwin to use .cfi_xxxx. The patch adds a target hook that allows non-ELF targets to use indirections appropriate to their needs. gcc/ChangeLog: * config/darwin-protos.h (darwin_make_eh_symbol_indirect): New. * config/darwin.c (darwin_make_eh_symbol_indirect): New. Use Mach-O semantics for personality and ldsa indirections. * config/darwin.h (TARGET_ASM_MAKE_EH_SYMBOL_INDIRECT): New. * doc/tm.texi: Regenerate. * doc/tm.texi.in: Add TARGET_ASM_MAKE_EH_SYMBOL_INDIRECT hook. * dwarf2out.c (dwarf2out_do_cfi_startproc): If the target defines a hook for indirecting personality and ldsa references, use that otherwise default to ELF semantics. * target.def (make_eh_symbol_indirect): New target hook. --- gcc/config/darwin-protos.h | 1 + gcc/config/darwin.c | 11 +++++++++++ gcc/config/darwin.h | 3 +++ gcc/doc/tm.texi | 4 ++++ gcc/doc/tm.texi.in | 2 ++ gcc/dwarf2out.c | 14 ++++++++++++-- gcc/target.def | 10 ++++++++++ 7 files changed, 43 insertions(+), 2 deletions(-) diff --git a/gcc/config/darwin-protos.h b/gcc/config/darwin-protos.h index 49c540fe08e..3f222c3bbdc 100644 --- a/gcc/config/darwin-protos.h +++ b/gcc/config/darwin-protos.h @@ -69,6 +69,7 @@ extern void darwin_non_lazy_pcrel (FILE *, rtx); extern void darwin_emit_unwind_label (FILE *, tree, int, int); extern void darwin_emit_except_table_label (FILE *); +extern rtx darwin_make_eh_symbol_indirect (rtx, bool); extern void darwin_pragma_ignore (struct cpp_reader *); extern void darwin_pragma_options (struct cpp_reader *); diff --git a/gcc/config/darwin.c b/gcc/config/darwin.c index dd4857f9e34..3265e3e6cb7 100644 --- a/gcc/config/darwin.c +++ b/gcc/config/darwin.c @@ -2225,6 +2225,17 @@ darwin_emit_except_table_label (FILE *file) ASM_OUTPUT_LABEL (file, section_start_label); } +rtx +darwin_make_eh_symbol_indirect (rtx orig, bool ARG_UNUSED (pubvis)) +{ + if (DARWIN_PPC == 0 && TARGET_64BIT) + return orig; + + return gen_rtx_SYMBOL_REF (Pmode, + machopic_indirection_name (orig, + /*stub_p=*/false)); +} + /* Return, and mark as used, the name of the stub for the mcount function. Currently, this is only called by X86 code in the expansion of the FUNCTION_PROFILER macro, when stubs are enabled. */ diff --git a/gcc/config/darwin.h b/gcc/config/darwin.h index f9d4fec30a0..5a766319cb0 100644 --- a/gcc/config/darwin.h +++ b/gcc/config/darwin.h @@ -591,6 +591,9 @@ extern GTY(()) int darwin_ms_struct; /* Emit a label to separate the exception table. */ #define TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL darwin_emit_except_table_label +/* Make an EH (personality or LDSA) symbol indirect as needed. */ +#define TARGET_ASM_MAKE_EH_SYMBOL_INDIRECT darwin_make_eh_symbol_indirect + /* Our profiling scheme doesn't LP labels and counter words. */ #define NO_PROFILE_COUNTERS 1 diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi index 833320ba7bf..a783a21f6cf 100644 --- a/gcc/doc/tm.texi +++ b/gcc/doc/tm.texi @@ -9560,6 +9560,10 @@ given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO} returns @code{UI_TARGET}. @end deftypefn +@deftypefn {Target Hook} rtx TARGET_ASM_MAKE_EH_SYMBOL_INDIRECT (rtx @var{origsymbol}, bool @var{pubvis}) +If necessary, modify personality and LSDA references to handle indirection. The original symbol is in @code{origsymbol} and if @code{pubvis} is true the symbol is visible outside the TU. +@end deftypefn + @deftypevr {Target Hook} bool TARGET_ASM_UNWIND_EMIT_BEFORE_INSN True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before the assembly for @var{insn} has been emitted, false if the hook should be called afterward. @end deftypevr diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in index 58109be3693..897f2896266 100644 --- a/gcc/doc/tm.texi.in +++ b/gcc/doc/tm.texi.in @@ -6456,6 +6456,8 @@ the jump-table. @hook TARGET_ASM_UNWIND_EMIT +@hook TARGET_ASM_MAKE_EH_SYMBOL_INDIRECT + @hook TARGET_ASM_UNWIND_EMIT_BEFORE_INSN @node Exception Region Output diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c index bc32a17efcd..bea02f9fbce 100644 --- a/gcc/dwarf2out.c +++ b/gcc/dwarf2out.c @@ -991,7 +991,12 @@ dwarf2out_do_cfi_startproc (bool second) in the assembler. Further, the assembler can't handle any of the weirder relocation types. */ if (enc & DW_EH_PE_indirect) - ref = dw2_force_const_mem (ref, true); + { + if (targetm.asm_out.make_eh_symbol_indirect != NULL) + ref = targetm.asm_out.make_eh_symbol_indirect (ref, true); + else + ref = dw2_force_const_mem (ref, true); + } fprintf (asm_out_file, "\t.cfi_personality %#x,", enc); output_addr_const (asm_out_file, ref); @@ -1009,7 +1014,12 @@ dwarf2out_do_cfi_startproc (bool second) SYMBOL_REF_FLAGS (ref) = SYMBOL_FLAG_LOCAL; if (enc & DW_EH_PE_indirect) - ref = dw2_force_const_mem (ref, true); + { + if (targetm.asm_out.make_eh_symbol_indirect != NULL) + ref = targetm.asm_out.make_eh_symbol_indirect (ref, true); + else + ref = dw2_force_const_mem (ref, true); + } fprintf (asm_out_file, "\t.cfi_lsda %#x,", enc); output_addr_const (asm_out_file, ref); diff --git a/gcc/target.def b/gcc/target.def index b916635be18..71411d85559 100644 --- a/gcc/target.def +++ b/gcc/target.def @@ -185,6 +185,16 @@ DEFHOOK void, (rtx personality), NULL) +/* If necessary, modify personality and LSDA references to handle + indirection. This is used when the assembler supports CFI directives. */ +DEFHOOK +(make_eh_symbol_indirect, + "If necessary, modify personality and LSDA references to handle indirection.\ + The original symbol is in @code{origsymbol} and if @code{pubvis} is true\ + the symbol is visible outside the TU.", + rtx, (rtx origsymbol, bool pubvis), + NULL) + /* Emit any directives required to unwind this instruction. */ DEFHOOK (unwind_emit, -- 2.30.2