commit 4361c221ff4b53f585a2e8c0ba38956c8132609f

Author: hjl <hjl@138bc75d-0d04-0410-961f-82ee72b054a4>

Date:   Mon Feb 26 15:29:30 2018 +0000

    i386: Update -mfunction-return= for return with pop

    When -mfunction-return= is used, simple_return_pop_internal should pop

    return address into ECX register, adjust stack by bytes to pop from stack

    and jump to the return thunk via ECX register.

    Tested on i686 and x86-64.

            PR target/84530

            * config/i386/i386-protos.h (ix86_output_indirect_jmp): Remove

            the bool argument.

            (ix86_output_indirect_function_return): New prototype.

            (ix86_split_simple_return_pop_internal): Likewise.

            * config/i386/i386.c (indirect_return_via_cx): New.

            (indirect_return_via_cx_bnd): Likewise.

            (indirect_thunk_name): Handle return va CX_REG.

            (output_indirect_thunk_function): Create alias for

            __x86_return_thunk_[re]cx and __x86_return_thunk_[re]cx_bnd.

            (ix86_output_indirect_jmp): Remove the bool argument.

            (ix86_output_indirect_function_return): New function.

            (ix86_split_simple_return_pop_internal): Likewise.

            * config/i386/i386.md (*indirect_jump): Don't pass false

            to ix86_output_indirect_jmp.

            (*tablejump_1): Likewise.

            (simple_return_pop_internal): Change it to define_insn_and_split.

            Call ix86_split_simple_return_pop_internal to split it for

            -mfunction-return=.

            (simple_return_indirect_internal): Call

            ix86_output_indirect_function_return instead of

            ix86_output_indirect_jmp.

    gcc/testsuite/

            PR target/84530

            * gcc.target/i386/ret-thunk-22.c: New test.

            * gcc.target/i386/ret-thunk-23.c: Likewise.

            * gcc.target/i386/ret-thunk-24.c: Likewise.

            * gcc.target/i386/ret-thunk-25.c: Likewise.

            * gcc.target/i386/ret-thunk-26.c: Likewise.

    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@257992 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/config/i386/i386-protos.h b/gcc/config/i386/i386-protos.h

index 4e4b2100f79..394d4aebf96 100644

--- a/gcc/config/i386/i386-protos.h

+++ b/gcc/config/i386/i386-protos.h

@@ -306,8 +306,10 @@ extern enum attr_cpu ix86_schedule;

 #endif

 extern const char * ix86_output_call_insn (rtx insn, rtx call_op);

-extern const char * ix86_output_indirect_jmp (rtx call_op, bool ret_p);

+extern const char * ix86_output_indirect_jmp (rtx call_op);

 extern const char * ix86_output_function_return (bool long_p);

+extern const char * ix86_output_indirect_function_return (rtx ret_op);

+extern void ix86_split_simple_return_pop_internal (rtx);

 #ifdef RTX_CODE

 /* Target data for multipass lookahead scheduling.

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c

index c25d26ca826..a8238a001ee 100644

--- a/gcc/config/i386/i386.c

+++ b/gcc/config/i386/i386.c

@@ -8777,6 +8777,9 @@ static bool indirect_thunk_needed = false;

    by call and return thunks functions.  */

 static int indirect_thunks_used;

+/* True if return thunk function via CX is needed.  */

+static bool indirect_return_via_cx;

+

 #ifndef INDIRECT_LABEL

 # define INDIRECT_LABEL "LIND"

 #endif

@@ -8786,26 +8789,29 @@ static int indirect_thunks_used;

 static void

 indirect_thunk_name (char name[32], int regno, bool ret_p)

 {

-  if (regno >= 0 && ret_p)

+  if (regno != INVALID_REGNUM && regno != CX_REG && ret_p)

     gcc_unreachable ();

   if (USE_HIDDEN_LINKONCE)

     {

-      if (regno >= 0)

+      const char *prefix;

+

+      prefix = "";

+

+      const char *ret = ret_p ? "return" : "indirect";

+

+      if (regno != INVALID_REGNUM)

 	{

 	  const char *reg_prefix;

 	  if (LEGACY_INT_REGNO_P (regno))

 	    reg_prefix = TARGET_64BIT ? "r" : "e";

 	  else

 	    reg_prefix = "";

-	  sprintf (name, "__x86_indirect_thunk_%s%s",

-		   reg_prefix, reg_names[regno]);

+	  sprintf (name, "__x86_%s_thunk%s_%s%s",

+		   ret, prefix, reg_prefix, reg_names[regno]);

 	}

       else

-	{

-	  const char *ret = ret_p ? "return" : "indirect";

-	  sprintf (name, "__x86_%s_thunk", ret);

-	}

+	sprintf (name, "__x86_%s_thunk%s", ret, prefix);

     }

   else

     {

@@ -8947,9 +8953,18 @@ output_indirect_thunk_function (int regno)

 	ASM_OUTPUT_LABEL (asm_out_file, name);

       }

-  if (regno < 0)

+  /* Create alias for __x86_return_thunk or

+     __x86_return_thunk_ecx.  */

+  bool need_alias;

+  if (regno == INVALID_REGNUM)

+    need_alias = true;

+  else if (regno == CX_REG)

+    need_alias = indirect_return_via_cx;

+  else

+    need_alias = false;

+

+  if (need_alias)

     {

-      /* Create alias for __x86.return_thunk/__x86.return_thunk_bnd.  */

       char alias[32];

       indirect_thunk_name (alias, regno, true);

@@ -24704,21 +24719,21 @@ ix86_output_indirect_branch (rtx call_op, const char *xasm,

   else

     ix86_output_indirect_branch_via_push (call_op, xasm, sibcall_p);

 }

+

 /* Output indirect jump.  CALL_OP is the jump target.  Jump is a

    function return if RET_P is true.  */

 const char *

-ix86_output_indirect_jmp (rtx call_op, bool ret_p)

+ix86_output_indirect_jmp (rtx call_op)

 {

   if (cfun->machine->indirect_branch_type != indirect_branch_keep)

     {

       struct ix86_frame frame;

       ix86_compute_frame_layout (&frame);

-      /* We can't have red-zone if this isn't a function return since

-	 "call" in the indirect thunk pushes the return address onto

-	 stack, destroying red-zone.  */

-      if (!ret_p && frame.red_zone_size != 0)

+      /* We can't have red-zone since "call" in the indirect thunk

+	 pushes the return address onto the stack, destroying the red-zone.  */

+      if (frame.red_zone_size != 0)

 	gcc_unreachable ();

       ix86_output_indirect_branch (call_op, "%0", true);

@@ -24759,6 +24774,75 @@ ix86_output_function_return (bool long_p)

   return "rep%; ret";

 }

+/* Output indirect function return.  RET_OP is the function return

+   target.  */

+

+const char *

+ix86_output_indirect_function_return (rtx ret_op)

+{

+  if (cfun->machine->function_return_type != indirect_branch_keep)

+    {

+      char thunk_name[32];

+      enum indirect_thunk_prefix need_prefix

+	= indirect_thunk_need_prefix (current_output_insn);

+      unsigned int regno = REGNO (ret_op);

+      gcc_assert (regno == CX_REG);

+

+      if (cfun->machine->function_return_type

+	  != indirect_branch_thunk_inline)

+	{

+	  bool need_thunk = (cfun->machine->function_return_type

+			     == indirect_branch_thunk);

+	  indirect_thunk_name (thunk_name, regno, need_prefix, true);

+	  if (need_thunk)

+	    {

+	      indirect_return_via_cx = true;

+	      indirect_thunks_used |= 1 << CX_REG;

+	    }

+	  fprintf (asm_out_file, "\tjmp\t%s\n", thunk_name);

+	}

+      else

+	output_indirect_thunk (need_prefix, regno);

+

+      return "";

+    }

+  else

+    return "jmp\t%A0";

+}

+

+/* Split simple return with popping POPC bytes from stack to indirect

+   branch with stack adjustment .  */

+

+void

+ix86_split_simple_return_pop_internal (rtx popc)

+{

+  struct machine_function *m = cfun->machine;

+  rtx ecx = gen_rtx_REG (SImode, CX_REG);

+  rtx insn;

+

+  /* There is no "pascal" calling convention in any 64bit ABI.  */

+  gcc_assert (!TARGET_64BIT);

+

+  insn = emit_insn (gen_pop (ecx));

+  m->fs.cfa_offset -= UNITS_PER_WORD;

+  m->fs.sp_offset -= UNITS_PER_WORD;

+

+  rtx x = plus_constant (Pmode, stack_pointer_rtx, UNITS_PER_WORD);

+  x = gen_rtx_SET (VOIDmode, stack_pointer_rtx, x);

+  add_reg_note (insn, REG_CFA_ADJUST_CFA, x);

+  add_reg_note (insn, REG_CFA_REGISTER, gen_rtx_SET (VOIDmode, ecx, pc_rtx));

+  RTX_FRAME_RELATED_P (insn) = 1;

+

+  x = gen_rtx_PLUS (Pmode, stack_pointer_rtx, popc);

+  x = gen_rtx_SET (VOIDmode, stack_pointer_rtx, x);

+  insn = emit_insn (x);

+  add_reg_note (insn, REG_CFA_ADJUST_CFA, x);

+  RTX_FRAME_RELATED_P (insn) = 1;

+

+  /* Now return address is in ECX.  */

+  emit_jump_insn (gen_simple_return_indirect_internal (ecx));

+}

+

 /* Output the assembly for a call instruction.  */

 const char *

diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md

index 228f8f6d77a..3320ec233d2 100644

--- a/gcc/config/i386/i386.md

+++ b/gcc/config/i386/i386.md

@@ -11282,7 +11282,7 @@

 (define_insn "*indirect_jump"

   [(set (pc) (match_operand:W 0 "indirect_branch_operand" "rw"))]

   ""

-  "* return ix86_output_indirect_jmp (operands[0], false);"

+  "* return ix86_output_indirect_jmp (operands[0]);"

   [(set (attr "type")

      (if_then_else (match_test "(cfun->machine->indirect_branch_type

 				 != indirect_branch_keep)")

@@ -11336,7 +11336,7 @@

   [(set (pc) (match_operand:W 0 "indirect_branch_operand" "rw"))

    (use (label_ref (match_operand 1)))]

   ""

-  "* return ix86_output_indirect_jmp (operands[0], false);"

+  "* return ix86_output_indirect_jmp (operands[0]);"

   [(set (attr "type")

      (if_then_else (match_test "(cfun->machine->indirect_branch_type

 				 != indirect_branch_keep)")

@@ -11769,11 +11769,14 @@

    (set_attr "prefix_rep" "1")

    (set_attr "modrm" "0")])

-(define_insn "simple_return_pop_internal"

+(define_insn_and_split "simple_return_pop_internal"

   [(simple_return)

    (use (match_operand:SI 0 "const_int_operand"))]

   "reload_completed"

   "ret\t%0"

+  "&& cfun->machine->function_return_type != indirect_branch_keep"

+  [(const_int 0)]

+  "ix86_split_simple_return_pop_internal (operands[0]); DONE;"

   [(set_attr "length" "3")

    (set_attr "atom_unit" "jeu")

    (set_attr "length_immediate" "2")

@@ -11783,7 +11786,7 @@

   [(simple_return)

    (use (match_operand:SI 0 "register_operand" "r"))]

   "reload_completed"

-  "* return ix86_output_indirect_jmp (operands[0], true);"

+  "* return ix86_output_indirect_function_return (operands[0]);"

   [(set (attr "type")

      (if_then_else (match_test "(cfun->machine->indirect_branch_type

 				 != indirect_branch_keep)")

diff --git a/gcc/testsuite/gcc.target/i386/ret-thunk-22.c b/gcc/testsuite/gcc.target/i386/ret-thunk-22.c

new file mode 100644

index 00000000000..89e086de97b

--- /dev/null

+++ b/gcc/testsuite/gcc.target/i386/ret-thunk-22.c

@@ -0,0 +1,15 @@

+/* PR target/r84530 */

+/* { dg-do compile { target ia32 } } */

+/* { dg-options "-O2 -mfunction-return=thunk" } */

+

+struct s { _Complex unsigned short x; };

+struct s gs = { 100 + 200i };

+struct s __attribute__((noinline)) foo (void) { return gs; }

+

+/* { dg-final { scan-assembler-times "popl\[\\t \]*%ecx" 1 } } */

+/* { dg-final { scan-assembler "lea\[l\]?\[\\t \]*4\\(%esp\\), %esp" } } */

+/* { dg-final { scan-assembler "jmp\[ \t\]*__x86_return_thunk_ecx" } } */

+/* { dg-final { scan-assembler "jmp\[ \t\]*\.LIND" } } */

+/* { dg-final { scan-assembler "call\[ \t\]*\.LIND" } } */

+/* { dg-final { scan-assembler {\tpause} } } */

+/* { dg-final { scan-assembler {\tlfence} } } */

diff --git a/gcc/testsuite/gcc.target/i386/ret-thunk-23.c b/gcc/testsuite/gcc.target/i386/ret-thunk-23.c

new file mode 100644

index 00000000000..43f0ccaa854

--- /dev/null

+++ b/gcc/testsuite/gcc.target/i386/ret-thunk-23.c

@@ -0,0 +1,15 @@

+/* PR target/r84530 */

+/* { dg-do compile { target ia32 } } */

+/* { dg-options "-O2 -mfunction-return=thunk-extern" } */

+

+struct s { _Complex unsigned short x; };

+struct s gs = { 100 + 200i };

+struct s __attribute__((noinline)) foo (void) { return gs; }

+

+/* { dg-final { scan-assembler-times "popl\[\\t \]*%ecx" 1 } } */

+/* { dg-final { scan-assembler "lea\[l\]?\[\\t \]*4\\(%esp\\), %esp" } } */

+/* { dg-final { scan-assembler "jmp\[ \t\]*__x86_return_thunk_ecx" } } */

+/* { dg-final { scan-assembler-not "jmp\[ \t\]*\.LIND" } } */

+/* { dg-final { scan-assembler-not "call\[ \t\]*\.LIND" } } */

+/* { dg-final { scan-assembler-not {\tpause} } } */

+/* { dg-final { scan-assembler-not {\tlfence} } } */

diff --git a/gcc/testsuite/gcc.target/i386/ret-thunk-24.c b/gcc/testsuite/gcc.target/i386/ret-thunk-24.c

new file mode 100644

index 00000000000..8729e35147e

--- /dev/null

+++ b/gcc/testsuite/gcc.target/i386/ret-thunk-24.c

@@ -0,0 +1,15 @@

+/* PR target/r84530 */

+/* { dg-do compile { target ia32 } } */

+/* { dg-options "-O2 -mfunction-return=thunk-inline" } */

+

+struct s { _Complex unsigned short x; };

+struct s gs = { 100 + 200i };

+struct s __attribute__((noinline)) foo (void) { return gs; }

+

+/* { dg-final { scan-assembler-times "popl\[\\t \]*%ecx" 1 } } */

+/* { dg-final { scan-assembler "lea\[l\]?\[\\t \]*4\\(%esp\\), %esp" } } */

+/* { dg-final { scan-assembler-not "jmp\[ \t\]*__x86_return_thunk_ecx" } } */

+/* { dg-final { scan-assembler "jmp\[ \t\]*\.LIND" } } */

+/* { dg-final { scan-assembler "call\[ \t\]*\.LIND" } } */

+/* { dg-final { scan-assembler {\tpause} } } */

+/* { dg-final { scan-assembler {\tlfence} } } */

diff --git a/gcc/testsuite/gcc.target/i386/ret-thunk-25.c b/gcc/testsuite/gcc.target/i386/ret-thunk-25.c

new file mode 100644

index 00000000000..f73553c9a9f

--- /dev/null

+++ b/gcc/testsuite/gcc.target/i386/ret-thunk-25.c

@@ -0,0 +1,14 @@

+/* PR target/r84530 */

+/* { dg-do compile { target ia32 } } */

+/* { dg-options "-O2 -mfunction-return=thunk -fno-pic" } */

+

+struct s { _Complex unsigned short x; };

+struct s gs = { 100 + 200i };

+struct s __attribute__((noinline)) foo (void) { return gs; }

+

+/* { dg-final { scan-assembler-times "popl\[\\t \]*%ecx" 1 } } */

+/* { dg-final { scan-assembler "lea\[l\]?\[\\t \]*4\\(%esp\\), %esp" } } */

+/* { dg-final { scan-assembler "jmp\[ \t\]*\.LIND" } } */

+/* { dg-final { scan-assembler "call\[ \t\]*\.LIND" } } */

+/* { dg-final { scan-assembler {\tpause} } } */

+/* { dg-final { scan-assembler {\tlfence} } } */

diff --git a/gcc/testsuite/gcc.target/i386/ret-thunk-26.c b/gcc/testsuite/gcc.target/i386/ret-thunk-26.c

new file mode 100644

index 00000000000..9144e988735

--- /dev/null

+++ b/gcc/testsuite/gcc.target/i386/ret-thunk-26.c

@@ -0,0 +1,40 @@

+/* PR target/r84530 */

+/* { dg-do run } */

+/* { dg-options "-Os -mfunction-return=thunk" } */

+

+struct S { int i; };

+__attribute__((const, noinline, noclone))

+struct S foo (int x)

+{

+  struct S s;

+  s.i = x;

+  return s;

+}

+

+int a[2048], b[2048], c[2048], d[2048];

+struct S e[2048];

+

+__attribute__((noinline, noclone)) void

+bar (void)

+{

+  int i;

+  for (i = 0; i < 1024; i++)

+    {

+      e[i] = foo (i);

+      a[i+2] = a[i] + a[i+1];

+      b[10] = b[10] + i;

+      c[i] = c[2047 - i];

+      d[i] = d[i + 1];

+    }

+}

+

+int

+main ()

+{

+  int i;

+  bar ();

+  for (i = 0; i < 1024; i++)

+    if (e[i].i != i)

+      __builtin_abort ();

+  return 0;

+}