Hi,
this is the breakage of SEH on 64-bit Windows introduced by defaulting to the
-freorder-blocks-and-partition optimization. It is fixed by:
1. Defining ASM_DECLARE_COLD_FUNCTION_NAME & ASM_DECLARE_COLD_FUNCTION_SIZE,
2. Emitting a nop in one more case for SEH,
3. Splitting the exception table into hot and cold parts; that's necessary
because the LSDA is referenced directly in the SEH scheme.
Tested on x86-64/Windows, x86-64/Linux and IA-64/Linux, OK for mainline?
2018-03-04 Eric Botcazou <ebotca...@adacore.com>
PR target/84277
* except.h (output_function_exception_table): Adjust prototype.
* except.c (output_function_exception_table): Remove FNNAME parameter
and
add SECTION parameter. Ouput one part of the table at a time.
* final.c (final_scan_insn_1) <NOTE_INSN_SWITCH_TEXT_SECTIONS>: Output
the first part of the exception table and emit unwind directives, if
any.
* config/i386/i386-protos.h (i386_pe_end_cold_function): Declare.
(i386_pe_seh_cold_init): Likewise.
* config/i386/cygming.h (ASM_DECLARE_COLD_FUNCTION_NAME): New macro.
(ASM_DECLARE_COLD_FUNCTION_SIZE): Likewise.
* config/i386/i386.c (x86_expand_epilogue): Fix wording in comment.
(ix86_output_call_insn): Emit a nop in one more case for SEH.
* config/i386/winnt.c: Include except.h.
(struct seh_frame_state): Add reg_offset, after_prologue,
in_cold_section.
(i386_pe_seh_end_prologue): Set seh->after_prologue.
(i386_pe_seh_cold_init): New function.
(i386_pe_seh_fini): Add COLD parameter and bail out if it is not equal
to seh->in_cold_section.
(seh_emit_push): Record the offset of the push.
(seh_emit_save): Record the offet of the save.
(i386_pe_seh_unwind_emit): Deal with NOTE_INSN_SWITCH_TEXT_SECTIONS.
Test seh->after_prologue to disregard the epilogue.
(i386_pe_end_function): Pass FALSE to i386_pe_seh_fini.
(i386_pe_end_cold_function): New function.
--
Eric BotcazouIndex: config/i386/cygming.h
===================================================================
--- config/i386/cygming.h (revision 258231)
+++ config/i386/cygming.h (working copy)
@@ -312,10 +312,27 @@ do { \
#define ASM_DECLARE_FUNCTION_NAME(FILE, NAME, DECL) \
i386_pe_start_function (FILE, NAME, DECL)
+/* Write the extra assembler code needed to declare the name of a
+ cold function partition properly. */
+
+#undef ASM_DECLARE_COLD_FUNCTION_NAME
+#define ASM_DECLARE_COLD_FUNCTION_NAME(FILE, NAME, DECL) \
+ do \
+ { \
+ i386_pe_declare_function_type (FILE, NAME, 0); \
+ i386_pe_seh_cold_init (FILE, NAME); \
+ ASM_OUTPUT_LABEL (FILE, NAME); \
+ } \
+ while (0)
+
#undef ASM_DECLARE_FUNCTION_SIZE
#define ASM_DECLARE_FUNCTION_SIZE(FILE,NAME,DECL) \
i386_pe_end_function (FILE, NAME, DECL)
+#undef ASM_DECLARE_COLD_FUNCTION_SIZE
+#define ASM_DECLARE_COLD_FUNCTION_SIZE(FILE,NAME,DECL) \
+ i386_pe_end_cold_function (FILE, NAME, DECL)
+
/* Add an external function to the list of functions to be declared at
the end of the file. */
#define ASM_OUTPUT_EXTERNAL(FILE, DECL, NAME) \
Index: config/i386/i386-protos.h
===================================================================
--- config/i386/i386-protos.h (revision 258231)
+++ config/i386/i386-protos.h (working copy)
@@ -256,6 +256,7 @@ extern void i386_pe_asm_output_aligned_d
extern void i386_pe_file_end (void);
extern void i386_pe_start_function (FILE *, const char *, tree);
extern void i386_pe_end_function (FILE *, const char *, tree);
+extern void i386_pe_end_cold_function (FILE *, const char *, tree);
extern void i386_pe_assemble_visibility (tree, int);
extern tree i386_pe_mangle_decl_assembler_name (tree, tree);
extern tree i386_pe_mangle_assembler_name (const char *);
@@ -263,6 +264,7 @@ extern void i386_pe_record_stub (const c
extern void i386_pe_seh_init (FILE *);
extern void i386_pe_seh_end_prologue (FILE *);
+extern void i386_pe_seh_cold_init (FILE *, const char *);
extern void i386_pe_seh_unwind_emit (FILE *, rtx_insn *);
extern void i386_pe_seh_emit_except_personality (rtx);
extern void i386_pe_seh_init_sections (void);
Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c (revision 258231)
+++ config/i386/i386.c (working copy)
@@ -14702,9 +14702,9 @@ ix86_expand_epilogue (int style)
if (TARGET_SEH)
{
/* Prevent a catch region from being adjacent to the standard
- epilogue sequence. Unfortuantely crtl->uses_eh_lsda nor
- several other flags that would be interesting to test are
- not yet set up. */
+ epilogue sequence. Unfortunately neither crtl->uses_eh_lsda
+ nor several other flags that would be interesting to test are
+ set up yet. */
if (flag_non_call_exceptions)
emit_insn (gen_nops (const1_rtx));
else
@@ -29206,6 +29206,14 @@ ix86_output_call_insn (rtx_insn *insn, r
for (i = NEXT_INSN (insn); i ; i = NEXT_INSN (i))
{
+ /* Prevent a catch region from being adjacent to a jump that would
+ be interpreted as an epilogue sequence by the unwinder. */
+ if (JUMP_P(i) && CROSSING_JUMP_P (i))
+ {
+ seh_nop_p = true;
+ break;
+ }
+
/* If we get to another real insn, we don't need the nop. */
if (INSN_P (i))
break;
Index: config/i386/winnt.c
===================================================================
--- config/i386/winnt.c (revision 258231)
+++ config/i386/winnt.c (working copy)
@@ -36,6 +36,7 @@ along with GCC; see the file COPYING3.
#include "emit-rtl.h"
#include "cgraph.h"
#include "lto-streamer.h"
+#include "except.h"
#include "output.h"
#include "varasm.h"
#include "lto-section-names.h"
@@ -820,6 +821,15 @@ struct seh_frame_state
/* The CFA is located at CFA_REG + CFA_OFFSET. */
HOST_WIDE_INT cfa_offset;
rtx cfa_reg;
+
+ /* The offset wrt the CFA where register N has been saved. */
+ HOST_WIDE_INT reg_offset[FIRST_PSEUDO_REGISTER];
+
+ /* True if we are past the end of the epilogue. */
+ bool after_prologue;
+
+ /* True if we are in the cold section. */
+ bool in_cold_section;
};
/* Set up data structures beginning output for SEH. */
@@ -850,10 +860,26 @@ i386_pe_seh_init (FILE *f)
fputc ('\n', f);
}
+/* Emit an assembler directive for the end of the prologue. */
+
void
i386_pe_seh_end_prologue (FILE *f)
{
+ if (!TARGET_SEH)
+ return;
+ if (cfun->is_thunk)
+ return;
+ cfun->machine->seh->after_prologue = true;
+ fputs ("\t.seh_endprologue\n", f);
+}
+
+/* Emit assembler directives to reconstruct the SEH state. */
+
+void
+i386_pe_seh_cold_init (FILE *f, const char *name)
+{
struct seh_frame_state *seh;
+ HOST_WIDE_INT offset;
if (!TARGET_SEH)
return;
@@ -861,19 +887,56 @@ i386_pe_seh_end_prologue (FILE *f)
return;
seh = cfun->machine->seh;
- XDELETE (seh);
- cfun->machine->seh = NULL;
+ fputs ("\t.seh_proc\t", f);
+ assemble_name (f, name);
+ fputc ('\n', f);
+
+ offset = seh->sp_offset - INCOMING_FRAME_SP_OFFSET;
+ if (offset > 0 && offset < SEH_MAX_FRAME_SIZE)
+ fprintf (f, "\t.seh_stackalloc\t" HOST_WIDE_INT_PRINT_DEC "\n", offset);
+
+ for (int regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++)
+ if (seh->reg_offset[regno] > 0)
+ {
+ fputs ((SSE_REGNO_P (regno) ? "\t.seh_savexmm\t"
+ : GENERAL_REGNO_P (regno) ? "\t.seh_savereg\t"
+ : (gcc_unreachable (), "")), f);
+ print_reg (gen_rtx_REG (DImode, regno), 0, f);
+ fprintf (f, ", " HOST_WIDE_INT_PRINT_DEC "\n",
+ seh->sp_offset - seh->reg_offset[regno]);
+ }
+
+ if (seh->cfa_reg != stack_pointer_rtx)
+ {
+ offset = seh->sp_offset - seh->cfa_offset;
+
+ gcc_assert ((offset & 15) == 0);
+ gcc_assert (IN_RANGE (offset, 0, 240));
+
+ fputs ("\t.seh_setframe\t", f);
+ print_reg (seh->cfa_reg, 0, f);
+ fprintf (f, ", " HOST_WIDE_INT_PRINT_DEC "\n", offset);
+ }
fputs ("\t.seh_endprologue\n", f);
}
+/* Emit an assembler directive for the end of the function. */
+
static void
-i386_pe_seh_fini (FILE *f)
+i386_pe_seh_fini (FILE *f, bool cold)
{
+ struct seh_frame_state *seh;
+
if (!TARGET_SEH)
return;
if (cfun->is_thunk)
return;
+ seh = cfun->machine->seh;
+ if (cold != seh->in_cold_section)
+ return;
+ XDELETE (seh);
+ cfun->machine->seh = NULL;
fputs ("\t.seh_endproc\n", f);
}
@@ -882,11 +945,12 @@ i386_pe_seh_fini (FILE *f)
static void
seh_emit_push (FILE *f, struct seh_frame_state *seh, rtx reg)
{
- unsigned int regno = REGNO (reg);
+ const unsigned int regno = REGNO (reg);
gcc_checking_assert (GENERAL_REGNO_P (regno));
seh->sp_offset += UNITS_PER_WORD;
+ seh->reg_offset[regno] = seh->sp_offset;
if (seh->cfa_reg == stack_pointer_rtx)
seh->cfa_offset += UNITS_PER_WORD;
@@ -901,9 +965,11 @@ static void
seh_emit_save (FILE *f, struct seh_frame_state *seh,
rtx reg, HOST_WIDE_INT cfa_offset)
{
- unsigned int regno = REGNO (reg);
+ const unsigned int regno = REGNO (reg);
HOST_WIDE_INT offset;
+ seh->reg_offset[regno] = cfa_offset;
+
/* Negative save offsets are of course not supported, since that
would be a store below the stack pointer and thus clobberable. */
gcc_assert (seh->sp_offset >= cfa_offset);
@@ -1112,15 +1178,21 @@ i386_pe_seh_unwind_emit (FILE *asm_out_f
if (!TARGET_SEH)
return;
- /* We free the SEH data once done with the prologue. Ignore those
- RTX_FRAME_RELATED_P insns that are associated with the epilogue. */
seh = cfun->machine->seh;
- if (seh == NULL)
- return;
+ if (NOTE_P (insn) && NOTE_KIND (insn) == NOTE_INSN_SWITCH_TEXT_SECTIONS)
+ {
+ fputs ("\t.seh_endproc\n", asm_out_file);
+ seh->in_cold_section = true;
+ return;
+ }
if (NOTE_P (insn) || !RTX_FRAME_RELATED_P (insn))
return;
+ /* Skip RTX_FRAME_RELATED_P insns that are associated with the epilogue. */
+ if (seh->after_prologue)
+ return;
+
for (note = REG_NOTES (insn); note ; note = XEXP (note, 1))
{
switch (REG_NOTE_KIND (note))
@@ -1227,8 +1299,13 @@ i386_pe_start_function (FILE *f, const c
void
i386_pe_end_function (FILE *f, const char *, tree)
{
- i386_pe_seh_fini (f);
+ i386_pe_seh_fini (f, false);
}
+void
+i386_pe_end_cold_function (FILE *f, const char *, tree)
+{
+ i386_pe_seh_fini (f, true);
+}
#include "gt-winnt.h"
Index: except.c
===================================================================
--- except.c (revision 258231)
+++ except.c (working copy)
@@ -3168,12 +3168,16 @@ output_one_function_exception_table (int
}
void
-output_function_exception_table (const char *fnname)
+output_function_exception_table (int section)
{
+ const char *fnname = get_fnname_from_decl (current_function_decl);
rtx personality = get_personality_function (current_function_decl);
/* Not all functions need anything. */
- if (! crtl->uses_eh_lsda)
+ if (!crtl->uses_eh_lsda)
+ return;
+
+ if (section == 1 && !crtl->eh.call_site_record_v[1])
return;
if (personality)
@@ -3189,9 +3193,7 @@ output_function_exception_table (const c
/* If the target wants a label to begin the table, emit it here. */
targetm.asm_out.emit_except_table_label (asm_out_file);
- output_one_function_exception_table (0);
- if (crtl->eh.call_site_record_v[1])
- output_one_function_exception_table (1);
+ output_one_function_exception_table (section);
switch_to_section (current_function_section ());
}
Index: except.h
===================================================================
--- except.h (revision 258231)
+++ except.h (working copy)
@@ -229,7 +229,7 @@ extern void remove_eh_handler (eh_region
extern void remove_unreachable_eh_regions (sbitmap);
extern bool current_function_has_exception_handlers (void);
-extern void output_function_exception_table (const char *);
+extern void output_function_exception_table (int);
extern rtx expand_builtin_eh_pointer (tree);
extern rtx expand_builtin_eh_filter (tree);
Index: final.c
===================================================================
--- final.c (revision 258231)
+++ final.c (working copy)
@@ -2265,6 +2265,11 @@ final_scan_insn_1 (rtx_insn *insn, FILE
case NOTE_INSN_SWITCH_TEXT_SECTIONS:
maybe_output_next_view (seen);
+ output_function_exception_table (0);
+
+ if (targetm.asm_out.unwind_emit)
+ targetm.asm_out.unwind_emit (asm_out_file, insn);
+
in_cold_section_p = !in_cold_section_p;
if (in_cold_section_p)
@@ -4672,7 +4677,7 @@ rest_of_handle_final (void)
/* The IA-64 ".handlerdata" directive must be issued before the ".endp"
directive that closes the procedure descriptor. Similarly, for x64 SEH.
Otherwise it's not strictly necessary, but it doesn't hurt either. */
- output_function_exception_table (fnname);
+ output_function_exception_table (crtl->has_bb_partition ? 1 : 0);
assemble_end_function (current_function_decl, fnname);
