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* [PATCH v2][GCC] arm: Add support for dwarf debug directives and pseudo hard-register for PAC feature.
@ 2022-05-05 11:02 Srinath Parvathaneni
  2022-07-04 18:33 ` Srinath Parvathaneni
  0 siblings, 1 reply; 5+ messages in thread
From: Srinath Parvathaneni @ 2022-05-05 11:02 UTC (permalink / raw)
  To: gcc-patches; +Cc: Kyrylo.Tkachov, Richard.Earnshaw

[-- Attachment #1: Type: text/plain, Size: 13434 bytes --]

Hello,

This patch teaches the DWARF support in gcc about RA_AUTH_CODE pseudo hard-register and also 
.save {ra_auth_code} and .cfi_offset ra_auth_code <offset> dwarf directives for the PAC feature
in Armv8.1-M architecture.

RA_AUTH_CODE register number is 107 and it's dwarf register number is 143.

When compiled with " -march=armv8.1-m.main -mbranch-protection=pac-ret+leaf+bti -mthumb
-mfloat-abi=soft -fasynchronous-unwind-tables -g -O2 -S" command line options, the assembly
output after this patch looks like below:

        ...
        .cfi_startproc
        pacbti  ip, lr, sp
        movs    r1, #40
        push    {ip, lr}
        .save {ra_auth_code, lr}
        .cfi_def_cfa_offset 8
        .cfi_offset 143, -8
        .cfi_offset 14, -4
        ...
        pop     {ip, lr}
        .cfi_restore 14
        .cfi_restore 143
        .cfi_def_cfa_offset 0
        movs    r0, #0
        aut     ip, lr, sp
        bx      lr
        .cfi_endproc
        ...

This patch can be committed after the patch at https://gcc.gnu.org/pipermail/gcc-patches/2021-November/583407.html
is committed.

Regression tested on arm-none-eabi target and found no regressions.

Ok for master?

Regards,
Srinath.

gcc/ChangeLog:

2022-04-06  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * config/arm/aout.h (ra_auth_code): Add to enum.
        * config/arm/arm.cc (emit_multi_reg_push): Add RA_AUTH_CODE register to
        dwarf frame expression.
        (arm_emit_multi_reg_pop): Restore RA_AUTH_CODE register.
        (arm_expand_prologue): Mark as frame related insn.
        (arm_regno_class): Check for pac pseudo reigster.
        (arm_dbx_register_number): Assign ra_auth_code register number in dwarf.
        (arm_unwind_emit_sequence): Print .save directive with ra_auth_code
        register.
        (arm_conditional_register_usage): Mark ra_auth_code in fixed reigsters.
        * config/arm/arm.h (FIRST_PSEUDO_REGISTER): Modify.
        (IS_PAC_Pseudo_REGNUM): Define.
        (enum reg_class): Add PAC_REG entry.
        * config/arm/arm.md (RA_AUTH_CODE): Define.

gcc/testsuite/ChangeLog:

2022-04-06  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * g++.target/arm/pac-1.C: New test.
        * gcc.target/arm/pac-9.c: Likewise.


###############     Attachment also inlined for ease of reply    ###############


diff --git a/gcc/config/arm/aout.h b/gcc/config/arm/aout.h
index b918ad3782fbee82320febb8b6e72ad615780261..ffeed45a678f17c63d5b42c21f020ca416cbf23f 100644
--- a/gcc/config/arm/aout.h
+++ b/gcc/config/arm/aout.h
@@ -74,7 +74,8 @@
   "wr8",   "wr9",   "wr10",  "wr11",				\
   "wr12",  "wr13",  "wr14",  "wr15",				\
   "wcgr0", "wcgr1", "wcgr2", "wcgr3",				\
-  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0"		\
+  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0",		\
+  "ra_auth_code"						\
 }
 #endif
 
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 3495ab857eac38ecdf37e55f1d201b1c35cbde0b..c77777067819f6785e44d30d8e5365505ab98682 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -816,7 +816,8 @@ extern const int arm_arch_cde_coproc_bits[];
 	s16-s31	      S	VFP variable (aka d8-d15).
 	vfpcc		Not a real register.  Represents the VFP condition
 			code flags.
-	vpr		Used to represent MVE VPR predication.  */
+	vpr		Used to represent MVE VPR predication.
+	ra_auth_code	Pseudo register to save PAC.  */
 
 /* The stack backtrace structure is as follows:
   fp points to here:  |  save code pointer  |      [fp]
@@ -857,7 +858,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,		\
   1,1,1,1,			\
   /* Specials.  */		\
-  1,1,1,1,1,1,1			\
+  1,1,1,1,1,1,1,1		\
 }
 
 /* 1 for registers not available across function calls.
@@ -887,7 +888,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,		\
   1,1,1,1,			\
   /* Specials.  */		\
-  1,1,1,1,1,1,1			\
+  1,1,1,1,1,1,1,1		\
 }
 
 #ifndef SUBTARGET_CONDITIONAL_REGISTER_USAGE
@@ -1063,10 +1064,10 @@ extern const int arm_arch_cde_coproc_bits[];
    && (LAST_VFP_REGNUM - (REGNUM) >= 2 * (N) - 1))
 
 /* The number of hard registers is 16 ARM + 1 CC + 1 SFP + 1 AFP
-   + 1 APSRQ + 1 APSRGE + 1 VPR.  */
+   + 1 APSRQ + 1 APSRGE + 1 VPR + 1 Pseudo register to save PAC.  */
 /* Intel Wireless MMX Technology registers add 16 + 4 more.  */
 /* VFP (VFP3) adds 32 (64) + 1 VFPCC.  */
-#define FIRST_PSEUDO_REGISTER   107
+#define FIRST_PSEUDO_REGISTER   108
 
 #define DBX_REGISTER_NUMBER(REGNO) arm_dbx_register_number (REGNO)
 
@@ -1253,12 +1254,15 @@ extern int arm_regs_in_sequence[];
   CC_REGNUM, VFPCC_REGNUM,			\
   FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM,	\
   SP_REGNUM, PC_REGNUM, APSRQ_REGNUM,		\
-  APSRGE_REGNUM, VPR_REGNUM			\
+  APSRGE_REGNUM, VPR_REGNUM, RA_AUTH_CODE	\
 }
 
 #define IS_VPR_REGNUM(REGNUM) \
   ((REGNUM) == VPR_REGNUM)
 
+#define IS_PAC_Pseudo_REGNUM(REGNUM) \
+  ((REGNUM) == RA_AUTH_CODE)
+
 /* Use different register alloc ordering for Thumb.  */
 #define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()
 
@@ -1297,6 +1301,7 @@ enum reg_class
   SFP_REG,
   AFP_REG,
   VPR_REG,
+  PAC_REG,
   GENERAL_AND_VPR_REGS,
   ALL_REGS,
   LIM_REG_CLASSES
@@ -1327,6 +1332,7 @@ enum reg_class
   "SFP_REG",		\
   "AFP_REG",		\
   "VPR_REG",		\
+  "PAC_REG",		\
   "GENERAL_AND_VPR_REGS", \
   "ALL_REGS"		\
 }
@@ -1356,6 +1362,7 @@ enum reg_class
   { 0x00000000, 0x00000000, 0x00000000, 0x00000040 }, /* SFP_REG */	\
   { 0x00000000, 0x00000000, 0x00000000, 0x00000080 }, /* AFP_REG */	\
   { 0x00000000, 0x00000000, 0x00000000, 0x00000400 }, /* VPR_REG.  */	\
+  { 0x00000000, 0x00000000, 0x00000000, 0x00000800 }, /* PAC_REG.  */	\
   { 0x00005FFF, 0x00000000, 0x00000000, 0x00000400 }, /* GENERAL_AND_VPR_REGS.  */ \
   { 0xFFFF7FFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0000040F }  /* ALL_REGS.  */	\
 }
diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc
index a2b720a666077c528034c13e27d7c7168cb824d7..a14ea47badd8b90315376c27553e5894beeea990 100644
--- a/gcc/config/arm/arm.cc
+++ b/gcc/config/arm/arm.cc
@@ -22151,7 +22151,9 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
     {
       if (mask & (1 << i))
 	{
-	  reg = gen_rtx_REG (SImode, i);
+	  rtx reg1 = reg = gen_rtx_REG (SImode, i);
+	  if (arm_current_function_pac_enabled_p () && i == IP_REGNUM)
+	    reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
 
 	  XVECEXP (par, 0, 0)
 	    = gen_rtx_SET (gen_frame_mem
@@ -22168,8 +22170,12 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
 
 	  if (dwarf_regs_mask & (1 << i))
 	    {
+	      /* Only the first register in the multi push instruction is stored
+		 to frame memory here.
+		Eg: push {r7 ,r8, ip, lr}
+		Only r7 is stored to frame memory here.  */
 	      tmp = gen_rtx_SET (gen_frame_mem (SImode, stack_pointer_rtx),
-				 reg);
+				 reg1);
 	      RTX_FRAME_RELATED_P (tmp) = 1;
 	      XVECEXP (dwarf, 0, dwarf_par_index++) = tmp;
 	    }
@@ -22182,18 +22188,25 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
     {
       if (mask & (1 << i))
 	{
-	  reg = gen_rtx_REG (SImode, i);
+	  rtx reg1 = reg = gen_rtx_REG (SImode, i);
+	  if (arm_current_function_pac_enabled_p () && i == IP_REGNUM)
+	    reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
 
 	  XVECEXP (par, 0, j) = gen_rtx_USE (VOIDmode, reg);
 
 	  if (dwarf_regs_mask & (1 << i))
 	    {
+	      /* Except the first register in the multi push instruction all the
+		 remaining registers are stored to frame memory here.
+		 Eg: push {r7, r8, ip, lr}
+		 r8, ip (ra_auth_code in case PACBTI enabled) and lr registers
+		 are stored to frame memory here.  */
 	      tmp
 		= gen_rtx_SET (gen_frame_mem
 			       (SImode,
 				plus_constant (Pmode, stack_pointer_rtx,
 					       4 * j)),
-			       reg);
+			       reg1);
 	      RTX_FRAME_RELATED_P (tmp) = 1;
 	      XVECEXP (dwarf, 0, dwarf_par_index++) = tmp;
 	    }
@@ -22278,7 +22291,9 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
   for (j = 0, i = 0; j < num_regs; i++)
     if (saved_regs_mask & (1 << i))
       {
-        reg = gen_rtx_REG (SImode, i);
+	rtx reg1 = reg = gen_rtx_REG (SImode, i);
+	if (arm_current_function_pac_enabled_p () && i == IP_REGNUM)
+	  reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
         if ((num_regs == 1) && emit_update && !return_in_pc)
           {
             /* Emit single load with writeback.  */
@@ -22286,7 +22301,7 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
                                  gen_rtx_POST_INC (Pmode,
                                                    stack_pointer_rtx));
             tmp = emit_insn (gen_rtx_SET (reg, tmp));
-            REG_NOTES (tmp) = alloc_reg_note (REG_CFA_RESTORE, reg, dwarf);
+	    REG_NOTES (tmp) = alloc_reg_note (REG_CFA_RESTORE, reg1, dwarf);
             return;
           }
 
@@ -22300,7 +22315,7 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
         /* We need to maintain a sequence for DWARF info too.  As dwarf info
            should not have PC, skip PC.  */
         if (i != PC_REGNUM)
-          dwarf = alloc_reg_note (REG_CFA_RESTORE, reg, dwarf);
+	  dwarf = alloc_reg_note (REG_CFA_RESTORE, reg1, dwarf);
 
         j++;
       }
@@ -25585,6 +25600,9 @@ arm_regno_class (int regno)
   if (IS_VPR_REGNUM (regno))
     return VPR_REG;
 
+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return PAC_REG;
+
   if (TARGET_THUMB1)
     {
       if (regno == STACK_POINTER_REGNUM)
@@ -29557,6 +29575,9 @@ arm_dbx_register_number (unsigned int regno)
   if (IS_IWMMXT_REGNUM (regno))
     return 112 + regno - FIRST_IWMMXT_REGNUM;
 
+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return 143;
+
   return DWARF_FRAME_REGISTERS;
 }
 
@@ -29678,6 +29699,11 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
       reg_size = 8;
       fprintf (out_file, "\t.vsave {");
     }
+  else if (IS_PAC_Pseudo_REGNUM (reg))
+    {
+      reg_size = 4;
+      fprintf (out_file, "\t.save {");
+    }
   else
     /* Unknown register type.  */
     gcc_unreachable ();
@@ -29707,6 +29733,8 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
 	 double precision register names.  */
       if (IS_VFP_REGNUM (reg))
 	asm_fprintf (out_file, "d%d", (reg - FIRST_VFP_REGNUM) / 2);
+      else if (IS_PAC_Pseudo_REGNUM (reg))
+	asm_fprintf (asm_out_file, "ra_auth_code");
       else
 	asm_fprintf (out_file, "%r", reg);
 
@@ -30575,7 +30603,10 @@ arm_conditional_register_usage (void)
     }
 
   if (TARGET_HAVE_PACBTI)
-    call_used_regs[IP_REGNUM] = 1;
+    {
+      call_used_regs[IP_REGNUM] = 1;
+      fixed_regs[RA_AUTH_CODE] = 0;
+    }
 
   /* The Q and GE bits are only accessed via special ACLE patterns.  */
   CLEAR_HARD_REG_BIT (operand_reg_set, APSRQ_REGNUM);
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 2221bc68f358f277eff176b7abab5adf1e952399..aaaf13574593846d02655d593d45d751a5b7512e 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -42,6 +42,7 @@
    (APSRQ_REGNUM    104)	; Q bit pseudo register
    (APSRGE_REGNUM   105)	; GE bits pseudo register
    (VPR_REGNUM      106)	; Vector Predication Register - MVE register.
+   (RA_AUTH_CODE    107)	; Pseudo register to save PAC.
   ]
 )
 ;; 3rd operand to select_dominance_cc_mode
diff --git a/gcc/testsuite/g++.target/arm/pac-1.C b/gcc/testsuite/g++.target/arm/pac-1.C
new file mode 100644
index 0000000000000000000000000000000000000000..b447213ab4e1b72cacd483efece077fbbca3a608
--- /dev/null
+++ b/gcc/testsuite/g++.target/arm/pac-1.C
@@ -0,0 +1,33 @@
+/* Check that GCC does .save and .cfi_offset directives with RA_AUTH_CODE pseudo hard-register.  */
+/* { dg-do compile } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-marm" "-mcpu=*" } } */
+/* { dg-options "-march=armv8.1-m.main -mbranch-protection=pac-ret+leaf+bti -mthumb -mfloat-abi=soft --save-temps -g" } */
+
+__attribute__((noinline)) void
+fn1 (int a, int b, int c)
+{
+  if (a != b + c)
+    __builtin_abort ();
+  else
+    throw b+c;
+}
+
+int main ()
+{
+  int a = 120;
+  try
+    {
+      fn1 (a, 40, 80);
+    }
+  catch (int x)
+    {
+      if (x != a)
+        __builtin_abort ();
+      else
+	return 0;
+    }
+}
+
+/* { dg-final { scan-assembler "\.save \{r7, ra_auth_code, lr\}" } } */
+/* { dg-final { scan-assembler "\.save \{r4, r7, ra_auth_code, lr\}" } } */
+/* { dg-final { scan-assembler "\.cfi_offset 143, \-8" } } */
diff --git a/gcc/testsuite/gcc.target/arm/pac-9.c b/gcc/testsuite/gcc.target/arm/pac-9.c
new file mode 100644
index 0000000000000000000000000000000000000000..2a69db6e8e8a32090a6c16ccc66871946188f8d8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pac-9.c
@@ -0,0 +1,21 @@
+/* Check that GCC does .save and .cfi_offset directives with RA_AUTH_CODE pseudo hard-register.  */
+/* { dg-do compile } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-marm" "-mcpu=*" } } */
+/* { dg-options "-march=armv8.1-m.main -mbranch-protection=pac-ret+leaf+bti -mthumb -mfloat-abi=soft -fasynchronous-unwind-tables --save-temps -g" } */
+
+__attribute__((noinline)) void
+fn1 (int a, int b, int c)
+{
+  if (a != b + c)
+    __builtin_abort ();
+}
+
+int main ()
+{
+  fn1 (40, 40, 80);
+  return 0;
+}
+
+/* { dg-final { scan-assembler "\.save \{r7, ra_auth_code, lr\}" } } */
+/* { dg-final { scan-assembler "\.save \{r3, r7, ra_auth_code, lr\}" } } */
+/* { dg-final { scan-assembler "\.cfi_offset 143, \-8" } } */


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diff --git a/gcc/config/arm/aout.h b/gcc/config/arm/aout.h
index b918ad3782fbee82320febb8b6e72ad615780261..ffeed45a678f17c63d5b42c21f020ca416cbf23f 100644
--- a/gcc/config/arm/aout.h
+++ b/gcc/config/arm/aout.h
@@ -74,7 +74,8 @@
   "wr8",   "wr9",   "wr10",  "wr11",				\
   "wr12",  "wr13",  "wr14",  "wr15",				\
   "wcgr0", "wcgr1", "wcgr2", "wcgr3",				\
-  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0"		\
+  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0",		\
+  "ra_auth_code"						\
 }
 #endif
 
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 3495ab857eac38ecdf37e55f1d201b1c35cbde0b..c77777067819f6785e44d30d8e5365505ab98682 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -816,7 +816,8 @@ extern const int arm_arch_cde_coproc_bits[];
 	s16-s31	      S	VFP variable (aka d8-d15).
 	vfpcc		Not a real register.  Represents the VFP condition
 			code flags.
-	vpr		Used to represent MVE VPR predication.  */
+	vpr		Used to represent MVE VPR predication.
+	ra_auth_code	Pseudo register to save PAC.  */
 
 /* The stack backtrace structure is as follows:
   fp points to here:  |  save code pointer  |      [fp]
@@ -857,7 +858,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,		\
   1,1,1,1,			\
   /* Specials.  */		\
-  1,1,1,1,1,1,1			\
+  1,1,1,1,1,1,1,1		\
 }
 
 /* 1 for registers not available across function calls.
@@ -887,7 +888,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,		\
   1,1,1,1,			\
   /* Specials.  */		\
-  1,1,1,1,1,1,1			\
+  1,1,1,1,1,1,1,1		\
 }
 
 #ifndef SUBTARGET_CONDITIONAL_REGISTER_USAGE
@@ -1063,10 +1064,10 @@ extern const int arm_arch_cde_coproc_bits[];
    && (LAST_VFP_REGNUM - (REGNUM) >= 2 * (N) - 1))
 
 /* The number of hard registers is 16 ARM + 1 CC + 1 SFP + 1 AFP
-   + 1 APSRQ + 1 APSRGE + 1 VPR.  */
+   + 1 APSRQ + 1 APSRGE + 1 VPR + 1 Pseudo register to save PAC.  */
 /* Intel Wireless MMX Technology registers add 16 + 4 more.  */
 /* VFP (VFP3) adds 32 (64) + 1 VFPCC.  */
-#define FIRST_PSEUDO_REGISTER   107
+#define FIRST_PSEUDO_REGISTER   108
 
 #define DBX_REGISTER_NUMBER(REGNO) arm_dbx_register_number (REGNO)
 
@@ -1253,12 +1254,15 @@ extern int arm_regs_in_sequence[];
   CC_REGNUM, VFPCC_REGNUM,			\
   FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM,	\
   SP_REGNUM, PC_REGNUM, APSRQ_REGNUM,		\
-  APSRGE_REGNUM, VPR_REGNUM			\
+  APSRGE_REGNUM, VPR_REGNUM, RA_AUTH_CODE	\
 }
 
 #define IS_VPR_REGNUM(REGNUM) \
   ((REGNUM) == VPR_REGNUM)
 
+#define IS_PAC_Pseudo_REGNUM(REGNUM) \
+  ((REGNUM) == RA_AUTH_CODE)
+
 /* Use different register alloc ordering for Thumb.  */
 #define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()
 
@@ -1297,6 +1301,7 @@ enum reg_class
   SFP_REG,
   AFP_REG,
   VPR_REG,
+  PAC_REG,
   GENERAL_AND_VPR_REGS,
   ALL_REGS,
   LIM_REG_CLASSES
@@ -1327,6 +1332,7 @@ enum reg_class
   "SFP_REG",		\
   "AFP_REG",		\
   "VPR_REG",		\
+  "PAC_REG",		\
   "GENERAL_AND_VPR_REGS", \
   "ALL_REGS"		\
 }
@@ -1356,6 +1362,7 @@ enum reg_class
   { 0x00000000, 0x00000000, 0x00000000, 0x00000040 }, /* SFP_REG */	\
   { 0x00000000, 0x00000000, 0x00000000, 0x00000080 }, /* AFP_REG */	\
   { 0x00000000, 0x00000000, 0x00000000, 0x00000400 }, /* VPR_REG.  */	\
+  { 0x00000000, 0x00000000, 0x00000000, 0x00000800 }, /* PAC_REG.  */	\
   { 0x00005FFF, 0x00000000, 0x00000000, 0x00000400 }, /* GENERAL_AND_VPR_REGS.  */ \
   { 0xFFFF7FFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0000040F }  /* ALL_REGS.  */	\
 }
diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc
index a2b720a666077c528034c13e27d7c7168cb824d7..a14ea47badd8b90315376c27553e5894beeea990 100644
--- a/gcc/config/arm/arm.cc
+++ b/gcc/config/arm/arm.cc
@@ -22151,7 +22151,9 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
     {
       if (mask & (1 << i))
 	{
-	  reg = gen_rtx_REG (SImode, i);
+	  rtx reg1 = reg = gen_rtx_REG (SImode, i);
+	  if (arm_current_function_pac_enabled_p () && i == IP_REGNUM)
+	    reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
 
 	  XVECEXP (par, 0, 0)
 	    = gen_rtx_SET (gen_frame_mem
@@ -22168,8 +22170,12 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
 
 	  if (dwarf_regs_mask & (1 << i))
 	    {
+	      /* Only the first register in the multi push instruction is stored
+		 to frame memory here.
+		Eg: push {r7 ,r8, ip, lr}
+		Only r7 is stored to frame memory here.  */
 	      tmp = gen_rtx_SET (gen_frame_mem (SImode, stack_pointer_rtx),
-				 reg);
+				 reg1);
 	      RTX_FRAME_RELATED_P (tmp) = 1;
 	      XVECEXP (dwarf, 0, dwarf_par_index++) = tmp;
 	    }
@@ -22182,18 +22188,25 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
     {
       if (mask & (1 << i))
 	{
-	  reg = gen_rtx_REG (SImode, i);
+	  rtx reg1 = reg = gen_rtx_REG (SImode, i);
+	  if (arm_current_function_pac_enabled_p () && i == IP_REGNUM)
+	    reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
 
 	  XVECEXP (par, 0, j) = gen_rtx_USE (VOIDmode, reg);
 
 	  if (dwarf_regs_mask & (1 << i))
 	    {
+	      /* Except the first register in the multi push instruction all the
+		 remaining registers are stored to frame memory here.
+		 Eg: push {r7, r8, ip, lr}
+		 r8, ip (ra_auth_code in case PACBTI enabled) and lr registers
+		 are stored to frame memory here.  */
 	      tmp
 		= gen_rtx_SET (gen_frame_mem
 			       (SImode,
 				plus_constant (Pmode, stack_pointer_rtx,
 					       4 * j)),
-			       reg);
+			       reg1);
 	      RTX_FRAME_RELATED_P (tmp) = 1;
 	      XVECEXP (dwarf, 0, dwarf_par_index++) = tmp;
 	    }
@@ -22278,7 +22291,9 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
   for (j = 0, i = 0; j < num_regs; i++)
     if (saved_regs_mask & (1 << i))
       {
-        reg = gen_rtx_REG (SImode, i);
+	rtx reg1 = reg = gen_rtx_REG (SImode, i);
+	if (arm_current_function_pac_enabled_p () && i == IP_REGNUM)
+	  reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
         if ((num_regs == 1) && emit_update && !return_in_pc)
           {
             /* Emit single load with writeback.  */
@@ -22286,7 +22301,7 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
                                  gen_rtx_POST_INC (Pmode,
                                                    stack_pointer_rtx));
             tmp = emit_insn (gen_rtx_SET (reg, tmp));
-            REG_NOTES (tmp) = alloc_reg_note (REG_CFA_RESTORE, reg, dwarf);
+	    REG_NOTES (tmp) = alloc_reg_note (REG_CFA_RESTORE, reg1, dwarf);
             return;
           }
 
@@ -22300,7 +22315,7 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
         /* We need to maintain a sequence for DWARF info too.  As dwarf info
            should not have PC, skip PC.  */
         if (i != PC_REGNUM)
-          dwarf = alloc_reg_note (REG_CFA_RESTORE, reg, dwarf);
+	  dwarf = alloc_reg_note (REG_CFA_RESTORE, reg1, dwarf);
 
         j++;
       }
@@ -25585,6 +25600,9 @@ arm_regno_class (int regno)
   if (IS_VPR_REGNUM (regno))
     return VPR_REG;
 
+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return PAC_REG;
+
   if (TARGET_THUMB1)
     {
       if (regno == STACK_POINTER_REGNUM)
@@ -29557,6 +29575,9 @@ arm_dbx_register_number (unsigned int regno)
   if (IS_IWMMXT_REGNUM (regno))
     return 112 + regno - FIRST_IWMMXT_REGNUM;
 
+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return 143;
+
   return DWARF_FRAME_REGISTERS;
 }
 
@@ -29678,6 +29699,11 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
       reg_size = 8;
       fprintf (out_file, "\t.vsave {");
     }
+  else if (IS_PAC_Pseudo_REGNUM (reg))
+    {
+      reg_size = 4;
+      fprintf (out_file, "\t.save {");
+    }
   else
     /* Unknown register type.  */
     gcc_unreachable ();
@@ -29707,6 +29733,8 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
 	 double precision register names.  */
       if (IS_VFP_REGNUM (reg))
 	asm_fprintf (out_file, "d%d", (reg - FIRST_VFP_REGNUM) / 2);
+      else if (IS_PAC_Pseudo_REGNUM (reg))
+	asm_fprintf (asm_out_file, "ra_auth_code");
       else
 	asm_fprintf (out_file, "%r", reg);
 
@@ -30575,7 +30603,10 @@ arm_conditional_register_usage (void)
     }
 
   if (TARGET_HAVE_PACBTI)
-    call_used_regs[IP_REGNUM] = 1;
+    {
+      call_used_regs[IP_REGNUM] = 1;
+      fixed_regs[RA_AUTH_CODE] = 0;
+    }
 
   /* The Q and GE bits are only accessed via special ACLE patterns.  */
   CLEAR_HARD_REG_BIT (operand_reg_set, APSRQ_REGNUM);
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 2221bc68f358f277eff176b7abab5adf1e952399..aaaf13574593846d02655d593d45d751a5b7512e 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -42,6 +42,7 @@
    (APSRQ_REGNUM    104)	; Q bit pseudo register
    (APSRGE_REGNUM   105)	; GE bits pseudo register
    (VPR_REGNUM      106)	; Vector Predication Register - MVE register.
+   (RA_AUTH_CODE    107)	; Pseudo register to save PAC.
   ]
 )
 ;; 3rd operand to select_dominance_cc_mode
diff --git a/gcc/testsuite/g++.target/arm/pac-1.C b/gcc/testsuite/g++.target/arm/pac-1.C
new file mode 100644
index 0000000000000000000000000000000000000000..b447213ab4e1b72cacd483efece077fbbca3a608
--- /dev/null
+++ b/gcc/testsuite/g++.target/arm/pac-1.C
@@ -0,0 +1,33 @@
+/* Check that GCC does .save and .cfi_offset directives with RA_AUTH_CODE pseudo hard-register.  */
+/* { dg-do compile } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-marm" "-mcpu=*" } } */
+/* { dg-options "-march=armv8.1-m.main -mbranch-protection=pac-ret+leaf+bti -mthumb -mfloat-abi=soft --save-temps -g" } */
+
+__attribute__((noinline)) void
+fn1 (int a, int b, int c)
+{
+  if (a != b + c)
+    __builtin_abort ();
+  else
+    throw b+c;
+}
+
+int main ()
+{
+  int a = 120;
+  try
+    {
+      fn1 (a, 40, 80);
+    }
+  catch (int x)
+    {
+      if (x != a)
+        __builtin_abort ();
+      else
+	return 0;
+    }
+}
+
+/* { dg-final { scan-assembler "\.save \{r7, ra_auth_code, lr\}" } } */
+/* { dg-final { scan-assembler "\.save \{r4, r7, ra_auth_code, lr\}" } } */
+/* { dg-final { scan-assembler "\.cfi_offset 143, \-8" } } */
diff --git a/gcc/testsuite/gcc.target/arm/pac-9.c b/gcc/testsuite/gcc.target/arm/pac-9.c
new file mode 100644
index 0000000000000000000000000000000000000000..2a69db6e8e8a32090a6c16ccc66871946188f8d8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pac-9.c
@@ -0,0 +1,21 @@
+/* Check that GCC does .save and .cfi_offset directives with RA_AUTH_CODE pseudo hard-register.  */
+/* { dg-do compile } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-marm" "-mcpu=*" } } */
+/* { dg-options "-march=armv8.1-m.main -mbranch-protection=pac-ret+leaf+bti -mthumb -mfloat-abi=soft -fasynchronous-unwind-tables --save-temps -g" } */
+
+__attribute__((noinline)) void
+fn1 (int a, int b, int c)
+{
+  if (a != b + c)
+    __builtin_abort ();
+}
+
+int main ()
+{
+  fn1 (40, 40, 80);
+  return 0;
+}
+
+/* { dg-final { scan-assembler "\.save \{r7, ra_auth_code, lr\}" } } */
+/* { dg-final { scan-assembler "\.save \{r3, r7, ra_auth_code, lr\}" } } */
+/* { dg-final { scan-assembler "\.cfi_offset 143, \-8" } } */


^ permalink raw reply	[flat|nested] 5+ messages in thread

* RE: [PATCH v2][GCC] arm: Add support for dwarf debug directives and pseudo hard-register for PAC feature.
  2022-05-05 11:02 [PATCH v2][GCC] arm: Add support for dwarf debug directives and pseudo hard-register for PAC feature Srinath Parvathaneni
@ 2022-07-04 18:33 ` Srinath Parvathaneni
  0 siblings, 0 replies; 5+ messages in thread
From: Srinath Parvathaneni @ 2022-07-04 18:33 UTC (permalink / raw)
  To: gcc-patches, Richard Earnshaw

Ping!!

> -----Original Message-----
> From: Gcc-patches <gcc-patches-
> bounces+srinath.parvathaneni=arm.com@gcc.gnu.org> On Behalf Of Srinath
> Parvathaneni via Gcc-patches
> Sent: 05 May 2022 12:02
> To: gcc-patches@gcc.gnu.org
> Cc: Richard Earnshaw <Richard.Earnshaw@arm.com>
> Subject: [PATCH v2][GCC] arm: Add support for dwarf debug directives and
> pseudo hard-register for PAC feature.
> 
> Hello,
> 
> This patch teaches the DWARF support in gcc about RA_AUTH_CODE pseudo
> hard-register and also .save {ra_auth_code} and .cfi_offset ra_auth_code
> <offset> dwarf directives for the PAC feature in Armv8.1-M architecture.
> 
> RA_AUTH_CODE register number is 107 and it's dwarf register number is 143.
> 
> When compiled with " -march=armv8.1-m.main -mbranch-protection=pac-
> ret+leaf+bti -mthumb -mfloat-abi=soft -fasynchronous-unwind-tables -g -O2
> -S" command line options, the assembly output after this patch looks like
> below:
> 
>         ...
>         .cfi_startproc
>         pacbti  ip, lr, sp
>         movs    r1, #40
>         push    {ip, lr}
>         .save {ra_auth_code, lr}
>         .cfi_def_cfa_offset 8
>         .cfi_offset 143, -8
>         .cfi_offset 14, -4
>         ...
>         pop     {ip, lr}
>         .cfi_restore 14
>         .cfi_restore 143
>         .cfi_def_cfa_offset 0
>         movs    r0, #0
>         aut     ip, lr, sp
>         bx      lr
>         .cfi_endproc
>         ...
> 
> This patch can be committed after the patch at
> https://gcc.gnu.org/pipermail/gcc-patches/2021-November/583407.html
> is committed.
> 
> Regression tested on arm-none-eabi target and found no regressions.
> 
> Ok for master?
> 
> Regards,
> Srinath.
> 
> gcc/ChangeLog:
> 
> 2022-04-06  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>
> 
>         * config/arm/aout.h (ra_auth_code): Add to enum.
>         * config/arm/arm.cc (emit_multi_reg_push): Add RA_AUTH_CODE
> register to
>         dwarf frame expression.
>         (arm_emit_multi_reg_pop): Restore RA_AUTH_CODE register.
>         (arm_expand_prologue): Mark as frame related insn.
>         (arm_regno_class): Check for pac pseudo reigster.
>         (arm_dbx_register_number): Assign ra_auth_code register number in
> dwarf.
>         (arm_unwind_emit_sequence): Print .save directive with ra_auth_code
>         register.
>         (arm_conditional_register_usage): Mark ra_auth_code in fixed reigsters.
>         * config/arm/arm.h (FIRST_PSEUDO_REGISTER): Modify.
>         (IS_PAC_Pseudo_REGNUM): Define.
>         (enum reg_class): Add PAC_REG entry.
>         * config/arm/arm.md (RA_AUTH_CODE): Define.
> 
> gcc/testsuite/ChangeLog:
> 
> 2022-04-06  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>
> 
>         * g++.target/arm/pac-1.C: New test.
>         * gcc.target/arm/pac-9.c: Likewise.
> 
> 
> ###############     Attachment also inlined for ease of reply
> ###############
> 
> 
> diff --git a/gcc/config/arm/aout.h b/gcc/config/arm/aout.h index
> b918ad3782fbee82320febb8b6e72ad615780261..ffeed45a678f17c63d5b42c2
> 1f020ca416cbf23f 100644
> --- a/gcc/config/arm/aout.h
> +++ b/gcc/config/arm/aout.h
> @@ -74,7 +74,8 @@
>    "wr8",   "wr9",   "wr10",  "wr11",				\
>    "wr12",  "wr13",  "wr14",  "wr15",				\
>    "wcgr0", "wcgr1", "wcgr2", "wcgr3",				\
> -  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0"		\
> +  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0",		\
> +  "ra_auth_code"						\
>  }
>  #endif
> 
> diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h index
> 3495ab857eac38ecdf37e55f1d201b1c35cbde0b..c77777067819f6785e44d30d
> 8e5365505ab98682 100644
> --- a/gcc/config/arm/arm.h
> +++ b/gcc/config/arm/arm.h
> @@ -816,7 +816,8 @@ extern const int arm_arch_cde_coproc_bits[];
>  	s16-s31	      S	VFP variable (aka d8-d15).
>  	vfpcc		Not a real register.  Represents the VFP condition
>  			code flags.
> -	vpr		Used to represent MVE VPR predication.  */
> +	vpr		Used to represent MVE VPR predication.
> +	ra_auth_code	Pseudo register to save PAC.  */
> 
>  /* The stack backtrace structure is as follows:
>    fp points to here:  |  save code pointer  |      [fp]
> @@ -857,7 +858,7 @@ extern const int arm_arch_cde_coproc_bits[];
>    1,1,1,1,1,1,1,1,		\
>    1,1,1,1,			\
>    /* Specials.  */		\
> -  1,1,1,1,1,1,1			\
> +  1,1,1,1,1,1,1,1		\
>  }
> 
>  /* 1 for registers not available across function calls.
> @@ -887,7 +888,7 @@ extern const int arm_arch_cde_coproc_bits[];
>    1,1,1,1,1,1,1,1,		\
>    1,1,1,1,			\
>    /* Specials.  */		\
> -  1,1,1,1,1,1,1			\
> +  1,1,1,1,1,1,1,1		\
>  }
> 
>  #ifndef SUBTARGET_CONDITIONAL_REGISTER_USAGE
> @@ -1063,10 +1064,10 @@ extern const int arm_arch_cde_coproc_bits[];
>     && (LAST_VFP_REGNUM - (REGNUM) >= 2 * (N) - 1))
> 
>  /* The number of hard registers is 16 ARM + 1 CC + 1 SFP + 1 AFP
> -   + 1 APSRQ + 1 APSRGE + 1 VPR.  */
> +   + 1 APSRQ + 1 APSRGE + 1 VPR + 1 Pseudo register to save PAC.  */
>  /* Intel Wireless MMX Technology registers add 16 + 4 more.  */
>  /* VFP (VFP3) adds 32 (64) + 1 VFPCC.  */
> -#define FIRST_PSEUDO_REGISTER   107
> +#define FIRST_PSEUDO_REGISTER   108
> 
>  #define DBX_REGISTER_NUMBER(REGNO) arm_dbx_register_number
> (REGNO)
> 
> @@ -1253,12 +1254,15 @@ extern int arm_regs_in_sequence[];
>    CC_REGNUM, VFPCC_REGNUM,			\
>    FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM,	\
>    SP_REGNUM, PC_REGNUM, APSRQ_REGNUM,		\
> -  APSRGE_REGNUM, VPR_REGNUM			\
> +  APSRGE_REGNUM, VPR_REGNUM, RA_AUTH_CODE	\
>  }
> 
>  #define IS_VPR_REGNUM(REGNUM) \
>    ((REGNUM) == VPR_REGNUM)
> 
> +#define IS_PAC_Pseudo_REGNUM(REGNUM) \
> +  ((REGNUM) == RA_AUTH_CODE)
> +
>  /* Use different register alloc ordering for Thumb.  */  #define
> ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()
> 
> @@ -1297,6 +1301,7 @@ enum reg_class
>    SFP_REG,
>    AFP_REG,
>    VPR_REG,
> +  PAC_REG,
>    GENERAL_AND_VPR_REGS,
>    ALL_REGS,
>    LIM_REG_CLASSES
> @@ -1327,6 +1332,7 @@ enum reg_class
>    "SFP_REG",		\
>    "AFP_REG",		\
>    "VPR_REG",		\
> +  "PAC_REG",		\
>    "GENERAL_AND_VPR_REGS", \
>    "ALL_REGS"		\
>  }
> @@ -1356,6 +1362,7 @@ enum reg_class
>    { 0x00000000, 0x00000000, 0x00000000, 0x00000040 }, /* SFP_REG */
> 	\
>    { 0x00000000, 0x00000000, 0x00000000, 0x00000080 }, /* AFP_REG */
> 	\
>    { 0x00000000, 0x00000000, 0x00000000, 0x00000400 }, /* VPR_REG.  */
> 	\
> +  { 0x00000000, 0x00000000, 0x00000000, 0x00000800 }, /* PAC_REG.  */
> 	\
>    { 0x00005FFF, 0x00000000, 0x00000000, 0x00000400 }, /*
> GENERAL_AND_VPR_REGS.  */ \
>    { 0xFFFF7FFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0000040F }  /* ALL_REGS.  */	\
>  }
> diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc index
> a2b720a666077c528034c13e27d7c7168cb824d7..a14ea47badd8b90315376c2
> 7553e5894beeea990 100644
> --- a/gcc/config/arm/arm.cc
> +++ b/gcc/config/arm/arm.cc
> @@ -22151,7 +22151,9 @@ emit_multi_reg_push (unsigned long mask,
> unsigned long dwarf_regs_mask)
>      {
>        if (mask & (1 << i))
>  	{
> -	  reg = gen_rtx_REG (SImode, i);
> +	  rtx reg1 = reg = gen_rtx_REG (SImode, i);
> +	  if (arm_current_function_pac_enabled_p () && i == IP_REGNUM)
> +	    reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
> 
>  	  XVECEXP (par, 0, 0)
>  	    = gen_rtx_SET (gen_frame_mem
> @@ -22168,8 +22170,12 @@ emit_multi_reg_push (unsigned long mask,
> unsigned long dwarf_regs_mask)
> 
>  	  if (dwarf_regs_mask & (1 << i))
>  	    {
> +	      /* Only the first register in the multi push instruction is stored
> +		 to frame memory here.
> +		Eg: push {r7 ,r8, ip, lr}
> +		Only r7 is stored to frame memory here.  */
>  	      tmp = gen_rtx_SET (gen_frame_mem (SImode, stack_pointer_rtx),
> -				 reg);
> +				 reg1);
>  	      RTX_FRAME_RELATED_P (tmp) = 1;
>  	      XVECEXP (dwarf, 0, dwarf_par_index++) = tmp;
>  	    }
> @@ -22182,18 +22188,25 @@ emit_multi_reg_push (unsigned long mask,
> unsigned long dwarf_regs_mask)
>      {
>        if (mask & (1 << i))
>  	{
> -	  reg = gen_rtx_REG (SImode, i);
> +	  rtx reg1 = reg = gen_rtx_REG (SImode, i);
> +	  if (arm_current_function_pac_enabled_p () && i == IP_REGNUM)
> +	    reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
> 
>  	  XVECEXP (par, 0, j) = gen_rtx_USE (VOIDmode, reg);
> 
>  	  if (dwarf_regs_mask & (1 << i))
>  	    {
> +	      /* Except the first register in the multi push instruction all the
> +		 remaining registers are stored to frame memory here.
> +		 Eg: push {r7, r8, ip, lr}
> +		 r8, ip (ra_auth_code in case PACBTI enabled) and lr registers
> +		 are stored to frame memory here.  */
>  	      tmp
>  		= gen_rtx_SET (gen_frame_mem
>  			       (SImode,
>  				plus_constant (Pmode, stack_pointer_rtx,
>  					       4 * j)),
> -			       reg);
> +			       reg1);
>  	      RTX_FRAME_RELATED_P (tmp) = 1;
>  	      XVECEXP (dwarf, 0, dwarf_par_index++) = tmp;
>  	    }
> @@ -22278,7 +22291,9 @@ arm_emit_multi_reg_pop (unsigned long
> saved_regs_mask)
>    for (j = 0, i = 0; j < num_regs; i++)
>      if (saved_regs_mask & (1 << i))
>        {
> -        reg = gen_rtx_REG (SImode, i);
> +	rtx reg1 = reg = gen_rtx_REG (SImode, i);
> +	if (arm_current_function_pac_enabled_p () && i == IP_REGNUM)
> +	  reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
>          if ((num_regs == 1) && emit_update && !return_in_pc)
>            {
>              /* Emit single load with writeback.  */ @@ -22286,7 +22301,7 @@
> arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
>                                   gen_rtx_POST_INC (Pmode,
>                                                     stack_pointer_rtx));
>              tmp = emit_insn (gen_rtx_SET (reg, tmp));
> -            REG_NOTES (tmp) = alloc_reg_note (REG_CFA_RESTORE, reg, dwarf);
> +	    REG_NOTES (tmp) = alloc_reg_note (REG_CFA_RESTORE, reg1,
> dwarf);
>              return;
>            }
> 
> @@ -22300,7 +22315,7 @@ arm_emit_multi_reg_pop (unsigned long
> saved_regs_mask)
>          /* We need to maintain a sequence for DWARF info too.  As dwarf info
>             should not have PC, skip PC.  */
>          if (i != PC_REGNUM)
> -          dwarf = alloc_reg_note (REG_CFA_RESTORE, reg, dwarf);
> +	  dwarf = alloc_reg_note (REG_CFA_RESTORE, reg1, dwarf);
> 
>          j++;
>        }
> @@ -25585,6 +25600,9 @@ arm_regno_class (int regno)
>    if (IS_VPR_REGNUM (regno))
>      return VPR_REG;
> 
> +  if (IS_PAC_Pseudo_REGNUM (regno))
> +    return PAC_REG;
> +
>    if (TARGET_THUMB1)
>      {
>        if (regno == STACK_POINTER_REGNUM) @@ -29557,6 +29575,9 @@
> arm_dbx_register_number (unsigned int regno)
>    if (IS_IWMMXT_REGNUM (regno))
>      return 112 + regno - FIRST_IWMMXT_REGNUM;
> 
> +  if (IS_PAC_Pseudo_REGNUM (regno))
> +    return 143;
> +
>    return DWARF_FRAME_REGISTERS;
>  }
> 
> @@ -29678,6 +29699,11 @@ arm_unwind_emit_sequence (FILE * out_file,
> rtx p)
>        reg_size = 8;
>        fprintf (out_file, "\t.vsave {");
>      }
> +  else if (IS_PAC_Pseudo_REGNUM (reg))
> +    {
> +      reg_size = 4;
> +      fprintf (out_file, "\t.save {");
> +    }
>    else
>      /* Unknown register type.  */
>      gcc_unreachable ();
> @@ -29707,6 +29733,8 @@ arm_unwind_emit_sequence (FILE * out_file, rtx
> p)
>  	 double precision register names.  */
>        if (IS_VFP_REGNUM (reg))
>  	asm_fprintf (out_file, "d%d", (reg - FIRST_VFP_REGNUM) / 2);
> +      else if (IS_PAC_Pseudo_REGNUM (reg))
> +	asm_fprintf (asm_out_file, "ra_auth_code");
>        else
>  	asm_fprintf (out_file, "%r", reg);
> 
> @@ -30575,7 +30603,10 @@ arm_conditional_register_usage (void)
>      }
> 
>    if (TARGET_HAVE_PACBTI)
> -    call_used_regs[IP_REGNUM] = 1;
> +    {
> +      call_used_regs[IP_REGNUM] = 1;
> +      fixed_regs[RA_AUTH_CODE] = 0;
> +    }
> 
>    /* The Q and GE bits are only accessed via special ACLE patterns.  */
>    CLEAR_HARD_REG_BIT (operand_reg_set, APSRQ_REGNUM); diff --git
> a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md index
> 2221bc68f358f277eff176b7abab5adf1e952399..aaaf13574593846d02655d59
> 3d45d751a5b7512e 100644
> --- a/gcc/config/arm/arm.md
> +++ b/gcc/config/arm/arm.md
> @@ -42,6 +42,7 @@
>     (APSRQ_REGNUM    104)	; Q bit pseudo register
>     (APSRGE_REGNUM   105)	; GE bits pseudo register
>     (VPR_REGNUM      106)	; Vector Predication Register - MVE register.
> +   (RA_AUTH_CODE    107)	; Pseudo register to save PAC.
>    ]
>  )
>  ;; 3rd operand to select_dominance_cc_mode diff --git
> a/gcc/testsuite/g++.target/arm/pac-1.C b/gcc/testsuite/g++.target/arm/pac-
> 1.C
> new file mode 100644
> index
> 0000000000000000000000000000000000000000..b447213ab4e1b72cacd483e
> fece077fbbca3a608
> --- /dev/null
> +++ b/gcc/testsuite/g++.target/arm/pac-1.C
> @@ -0,0 +1,33 @@
> +/* Check that GCC does .save and .cfi_offset directives with
> +RA_AUTH_CODE pseudo hard-register.  */
> +/* { dg-do compile } */
> +/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } {
> +"-marm" "-mcpu=*" } } */
> +/* { dg-options "-march=armv8.1-m.main
> +-mbranch-protection=pac-ret+leaf+bti -mthumb -mfloat-abi=soft
> +--save-temps -g" } */
> +
> +__attribute__((noinline)) void
> +fn1 (int a, int b, int c)
> +{
> +  if (a != b + c)
> +    __builtin_abort ();
> +  else
> +    throw b+c;
> +}
> +
> +int main ()
> +{
> +  int a = 120;
> +  try
> +    {
> +      fn1 (a, 40, 80);
> +    }
> +  catch (int x)
> +    {
> +      if (x != a)
> +        __builtin_abort ();
> +      else
> +	return 0;
> +    }
> +}
> +
> +/* { dg-final { scan-assembler "\.save \{r7, ra_auth_code, lr\}" } } */
> +/* { dg-final { scan-assembler "\.save \{r4, r7, ra_auth_code, lr\}" }
> +} */
> +/* { dg-final { scan-assembler "\.cfi_offset 143, \-8" } } */
> diff --git a/gcc/testsuite/gcc.target/arm/pac-9.c
> b/gcc/testsuite/gcc.target/arm/pac-9.c
> new file mode 100644
> index
> 0000000000000000000000000000000000000000..2a69db6e8e8a32090a6c16c
> cc66871946188f8d8
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/arm/pac-9.c
> @@ -0,0 +1,21 @@
> +/* Check that GCC does .save and .cfi_offset directives with
> +RA_AUTH_CODE pseudo hard-register.  */
> +/* { dg-do compile } */
> +/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } {
> +"-marm" "-mcpu=*" } } */
> +/* { dg-options "-march=armv8.1-m.main
> +-mbranch-protection=pac-ret+leaf+bti -mthumb -mfloat-abi=soft
> +-fasynchronous-unwind-tables --save-temps -g" } */
> +
> +__attribute__((noinline)) void
> +fn1 (int a, int b, int c)
> +{
> +  if (a != b + c)
> +    __builtin_abort ();
> +}
> +
> +int main ()
> +{
> +  fn1 (40, 40, 80);
> +  return 0;
> +}
> +
> +/* { dg-final { scan-assembler "\.save \{r7, ra_auth_code, lr\}" } } */
> +/* { dg-final { scan-assembler "\.save \{r3, r7, ra_auth_code, lr\}" }
> +} */
> +/* { dg-final { scan-assembler "\.cfi_offset 143, \-8" } } */


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2][GCC] arm: Add support for dwarf debug directives and pseudo hard-register for PAC feature.
  2021-12-13 10:44 ` Srinath Parvathaneni
@ 2022-01-12 13:45   ` Srinath Parvathaneni
  0 siblings, 0 replies; 5+ messages in thread
From: Srinath Parvathaneni @ 2022-01-12 13:45 UTC (permalink / raw)
  To: gcc-patches; +Cc: Kyrylo Tkachov, Richard Earnshaw, Tejas Belagod

Ping!!
________________________________
From: Srinath Parvathaneni <Srinath.Parvathaneni@arm.com>
Sent: 13 December 2021 10:44
To: gcc-patches@gcc.gnu.org <gcc-patches@gcc.gnu.org>
Cc: Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>; Richard Earnshaw <Richard.Earnshaw@arm.com>; Tejas Belagod <Tejas.Belagod@arm.com>
Subject: Re: [PATCH v2][GCC] arm: Add support for dwarf debug directives and pseudo hard-register for PAC feature.

Ping!!
________________________________
From: Srinath Parvathaneni
Sent: 12 November 2021 18:03
To: gcc-patches@gcc.gnu.org <gcc-patches@gcc.gnu.org>
Cc: Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>; Richard Earnshaw <Richard.Earnshaw@arm.com>; Tejas Belagod <Tejas.Belagod@arm.com>
Subject: [PATCH v2][GCC] arm: Add support for dwarf debug directives and pseudo hard-register for PAC feature.

Hello,

This patch teaches the DWARF support in gcc about RA_AUTH_CODE pseudo hard-register and also
.save {ra_auth_code} and .cfi_offset ra_auth_code <offset> dwarf directives for the PAC feature
in Armv8.1-M architecture.

RA_AUTH_CODE register number is 107 and it's dwarf register number is 143.

When compiled with "arm-none-eabi-gcc -O2  -mthumb -march=armv8.1-m.main+pacbti -S -fasynchronous-unwind-tables -g"
command line options, the directives supported in this patch looks like below:

        ...
        push    {ip}
        .save {ra_auth_code}
        .cfi_def_cfa_offset 8
        .cfi_offset 143, -8
        ...

This patch can be committed after the patch at https://gcc.gnu.org/pipermail/gcc-patches/2021-November/583407.html
is committed.

Regression tested on arm-none-eabi target and found no regressions.

Ok for master?

Regards,
Srinath.

gcc/ChangeLog:

2021-11-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * config/arm/aout.h (ra_auth_code): Add to enum.
        * config/arm/arm.c (emit_multi_reg_push): Add RA_AUTH_CODE register to
        dwarf frame expression instead of IP_REGNUM.
        (arm_expand_prologue): Mark as frame related insn.
        (arm_regno_class): Check for pac pseudo reigster.
        (arm_dbx_register_number): Assign ra_auth_code register number in dwarf.
        (arm_unwind_emit_sequence): Print .save directive with ra_auth_code
        register.
        (arm_conditional_register_usage): Mark ra_auth_code in fixed reigsters.
        * config/arm/arm.h (FIRST_PSEUDO_REGISTER): Modify.
        (IS_PAC_Pseudo_REGNUM): Define.
        (enum reg_class): Add PAC_REG entry.
        * config/arm/arm.md (RA_AUTH_CODE): Define.

gcc/testsuite/ChangeLog:

2021-11-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * g++.target/arm/pac-1.C: New test.


###############     Attachment also inlined for ease of reply    ###############


diff --git a/gcc/config/arm/aout.h b/gcc/config/arm/aout.h
index 25a2812a663742893b928398b0d3948e97f1905b..c69e299e012f46c8d0711830125dbf2f6b2e93d7 100644
--- a/gcc/config/arm/aout.h
+++ b/gcc/config/arm/aout.h
@@ -74,7 +74,8 @@
   "wr8",   "wr9",   "wr10",  "wr11",                           \
   "wr12",  "wr13",  "wr14",  "wr15",                           \
   "wcgr0", "wcgr1", "wcgr2", "wcgr3",                          \
-  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0"         \
+  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0",                \
+  "ra_auth_code"                                               \
 }
 #endif

diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 8e6ef41f6b065217d1af3f4f1cb85b2d8fbd0dc0..f31944e85c9ab83501f156d138e2aea1bcb5b79d 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -815,7 +815,8 @@ extern const int arm_arch_cde_coproc_bits[];
         s16-s31       S  VFP variable (aka d8-d15).
         vfpcc           Not a real register.  Represents the VFP condition
                         code flags.
-       vpr             Used to represent MVE VPR predication.  */
+       vpr             Used to represent MVE VPR predication.
+       ra_auth_code    Pseudo register to save PAC.  */

 /* The stack backtrace structure is as follows:
   fp points to here:  |  save code pointer  |      [fp]
@@ -856,7 +857,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,             \
   1,1,1,1,                     \
   /* Specials.  */             \
-  1,1,1,1,1,1,1                        \
+  1,1,1,1,1,1,1,1              \
 }

 /* 1 for registers not available across function calls.
@@ -886,7 +887,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,             \
   1,1,1,1,                     \
   /* Specials.  */             \
-  1,1,1,1,1,1,1                        \
+  1,1,1,1,1,1,1,1              \
 }

 #ifndef SUBTARGET_CONDITIONAL_REGISTER_USAGE
@@ -1062,10 +1063,10 @@ extern const int arm_arch_cde_coproc_bits[];
    && (LAST_VFP_REGNUM - (REGNUM) >= 2 * (N) - 1))

 /* The number of hard registers is 16 ARM + 1 CC + 1 SFP + 1 AFP
-   + 1 APSRQ + 1 APSRGE + 1 VPR.  */
+   + 1 APSRQ + 1 APSRGE + 1 VPR + 1 Pseudo register to save PAC.  */
 /* Intel Wireless MMX Technology registers add 16 + 4 more.  */
 /* VFP (VFP3) adds 32 (64) + 1 VFPCC.  */
-#define FIRST_PSEUDO_REGISTER   107
+#define FIRST_PSEUDO_REGISTER   108

 #define DBX_REGISTER_NUMBER(REGNO) arm_dbx_register_number (REGNO)

@@ -1248,12 +1249,15 @@ extern int arm_regs_in_sequence[];
   CC_REGNUM, VFPCC_REGNUM,                     \
   FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM,    \
   SP_REGNUM, PC_REGNUM, APSRQ_REGNUM,          \
-  APSRGE_REGNUM, VPR_REGNUM                    \
+  APSRGE_REGNUM, VPR_REGNUM, RA_AUTH_CODE      \
 }

 #define IS_VPR_REGNUM(REGNUM) \
   ((REGNUM) == VPR_REGNUM)

+#define IS_PAC_Pseudo_REGNUM(REGNUM) \
+  ((REGNUM) == RA_AUTH_CODE)
+
 /* Use different register alloc ordering for Thumb.  */
 #define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()

@@ -1292,6 +1296,7 @@ enum reg_class
   SFP_REG,
   AFP_REG,
   VPR_REG,
+  PAC_REG,
   ALL_REGS,
   LIM_REG_CLASSES
 };
@@ -1321,6 +1326,7 @@ enum reg_class
   "SFP_REG",           \
   "AFP_REG",           \
   "VPR_REG",           \
+  "PAC_REG",           \
   "ALL_REGS"           \
 }

@@ -1349,6 +1355,7 @@ enum reg_class
   { 0x00000000, 0x00000000, 0x00000000, 0x00000040 }, /* SFP_REG */    \
   { 0x00000000, 0x00000000, 0x00000000, 0x00000080 }, /* AFP_REG */    \
   { 0x00000000, 0x00000000, 0x00000000, 0x00000400 }, /* VPR_REG.  */  \
+  { 0x00000000, 0x00000000, 0x00000000, 0x00000800 }, /* PAC_REG.  */  \
   { 0xFFFF7FFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0000000F }  /* ALL_REGS.  */ \
 }

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index a3e34747ba52840bd82f76df4a3f05704bd42ec1..966c49a3bf21de909dbab5abcac5d1d3b2af4262 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -22000,7 +22000,9 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
     {
       if (mask & (1 << i))
         {
-         reg = gen_rtx_REG (SImode, i);
+         rtx reg1 = reg = gen_rtx_REG (SImode, i);
+         if (arm_pac_enabled_for_curr_function_p () && i == IP_REGNUM)
+           reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);

           XVECEXP (par, 0, 0)
             = gen_rtx_SET (gen_frame_mem
@@ -22018,7 +22020,7 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
           if (dwarf_regs_mask & (1 << i))
             {
               tmp = gen_rtx_SET (gen_frame_mem (SImode, stack_pointer_rtx),
-                                reg);
+                                reg1);
               RTX_FRAME_RELATED_P (tmp) = 1;
               XVECEXP (dwarf, 0, dwarf_par_index++) = tmp;
             }
@@ -23505,7 +23507,10 @@ arm_expand_prologue (void)
     saved_regs += arm_save_coproc_regs ();

   if (arm_pac_enabled_for_curr_function_p ())
-      emit_multi_reg_push (1 << IP_REGNUM, 1 << IP_REGNUM);
+    {
+      insn = emit_multi_reg_push (1 << IP_REGNUM, 1 << IP_REGNUM);
+      RTX_FRAME_RELATED_P (insn) = 1;
+    }

   if (frame_pointer_needed && TARGET_ARM)
     {
@@ -25435,6 +25440,9 @@ arm_regno_class (int regno)
   if (IS_VPR_REGNUM (regno))
     return VPR_REG;

+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return PAC_REG;
+
   if (TARGET_THUMB1)
     {
       if (regno == STACK_POINTER_REGNUM)
@@ -29429,6 +29437,9 @@ arm_dbx_register_number (unsigned int regno)
   if (IS_IWMMXT_REGNUM (regno))
     return 112 + regno - FIRST_IWMMXT_REGNUM;

+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return 143;
+
   return DWARF_FRAME_REGISTERS;
 }

@@ -29550,6 +29561,11 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
       reg_size = 8;
       fprintf (out_file, "\t.vsave {");
     }
+  else if (IS_PAC_Pseudo_REGNUM (reg))
+    {
+      reg_size = 4;
+      fprintf (out_file, "\t.save {");
+    }
   else
     /* Unknown register type.  */
     gcc_unreachable ();
@@ -29579,6 +29595,8 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
          double precision register names.  */
       if (IS_VFP_REGNUM (reg))
         asm_fprintf (out_file, "d%d", (reg - FIRST_VFP_REGNUM) / 2);
+      else if (IS_PAC_Pseudo_REGNUM (reg))
+       asm_fprintf (asm_out_file, "ra_auth_code");
       else
         asm_fprintf (out_file, "%r", reg);

@@ -30447,7 +30465,10 @@ arm_conditional_register_usage (void)
     }

   if (TARGET_HAVE_PACBTI)
-    call_used_regs[IP_REGNUM] = 1;
+    {
+      call_used_regs[IP_REGNUM] = 1;
+      fixed_regs[RA_AUTH_CODE] = 0;
+    }

   /* The Q and GE bits are only accessed via special ACLE patterns.  */
   CLEAR_HARD_REG_BIT (operand_reg_set, APSRQ_REGNUM);
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 564170dc4500c2c5d961c9a19dd86a31416dc965..f27dc3f9041d8b32e7ad750c39143a6764156fe9 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -42,6 +42,7 @@
    (APSRQ_REGNUM    104)       ; Q bit pseudo register
    (APSRGE_REGNUM   105)       ; GE bits pseudo register
    (VPR_REGNUM      106)       ; Vector Predication Register - MVE register.
+   (RA_AUTH_CODE    107)       ; Pseudo register to save PAC.
   ]
 )
 ;; 3rd operand to select_dominance_cc_mode
diff --git a/gcc/testsuite/g++.target/arm/pac-1.C b/gcc/testsuite/g++.target/arm/pac-1.C
new file mode 100644
index 0000000000000000000000000000000000000000..d33c860f1e368581dd9c3552a7201c7932b8560f
--- /dev/null
+++ b/gcc/testsuite/g++.target/arm/pac-1.C
@@ -0,0 +1,32 @@
+/* Check that GCC does .save and .cfi_offset directives with RA_AUTH_CODE pseudo hard-register.  */
+/* { dg-do compile } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-marm" "-mcpu=*" } } */
+/* { dg-options "-O2 -march=armv8.1-m.main -mbranch-protection=pac-ret+leaf+bti -mthumb -mfloat-abi=soft --save-temps -g" } */
+
+__attribute__((noinline)) void
+fn1 (int a, int b, int c)
+{
+  if (a != b + c)
+    __builtin_abort ();
+  else
+    throw b+c;
+}
+
+int main ()
+{
+  int a = 120;
+  try
+    {
+      fn1 (a, 40, 80);
+    }
+  catch (int x)
+    {
+      if (x != a)
+        __builtin_abort ();
+      else
+       return 0;
+    }
+}
+
+/* { dg-final { scan-assembler "\.save \{ra_auth_code\}" } } */
+/* { dg-final { scan-assembler "\.cfi_offset 143, \-8" } } */


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2][GCC] arm: Add support for dwarf debug directives and pseudo hard-register for PAC feature.
  2021-11-12 18:02 Srinath Parvathaneni
@ 2021-12-13 10:44 ` Srinath Parvathaneni
  2022-01-12 13:45   ` Srinath Parvathaneni
  0 siblings, 1 reply; 5+ messages in thread
From: Srinath Parvathaneni @ 2021-12-13 10:44 UTC (permalink / raw)
  To: gcc-patches; +Cc: Kyrylo Tkachov, Richard Earnshaw, Tejas Belagod

Ping!!
________________________________
From: Srinath Parvathaneni
Sent: 12 November 2021 18:03
To: gcc-patches@gcc.gnu.org <gcc-patches@gcc.gnu.org>
Cc: Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>; Richard Earnshaw <Richard.Earnshaw@arm.com>; Tejas Belagod <Tejas.Belagod@arm.com>
Subject: [PATCH v2][GCC] arm: Add support for dwarf debug directives and pseudo hard-register for PAC feature.

Hello,

This patch teaches the DWARF support in gcc about RA_AUTH_CODE pseudo hard-register and also
.save {ra_auth_code} and .cfi_offset ra_auth_code <offset> dwarf directives for the PAC feature
in Armv8.1-M architecture.

RA_AUTH_CODE register number is 107 and it's dwarf register number is 143.

When compiled with "arm-none-eabi-gcc -O2  -mthumb -march=armv8.1-m.main+pacbti -S -fasynchronous-unwind-tables -g"
command line options, the directives supported in this patch looks like below:

        ...
        push    {ip}
        .save {ra_auth_code}
        .cfi_def_cfa_offset 8
        .cfi_offset 143, -8
        ...

This patch can be committed after the patch at https://gcc.gnu.org/pipermail/gcc-patches/2021-November/583407.html
is committed.

Regression tested on arm-none-eabi target and found no regressions.

Ok for master?

Regards,
Srinath.

gcc/ChangeLog:

2021-11-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * config/arm/aout.h (ra_auth_code): Add to enum.
        * config/arm/arm.c (emit_multi_reg_push): Add RA_AUTH_CODE register to
        dwarf frame expression instead of IP_REGNUM.
        (arm_expand_prologue): Mark as frame related insn.
        (arm_regno_class): Check for pac pseudo reigster.
        (arm_dbx_register_number): Assign ra_auth_code register number in dwarf.
        (arm_unwind_emit_sequence): Print .save directive with ra_auth_code
        register.
        (arm_conditional_register_usage): Mark ra_auth_code in fixed reigsters.
        * config/arm/arm.h (FIRST_PSEUDO_REGISTER): Modify.
        (IS_PAC_Pseudo_REGNUM): Define.
        (enum reg_class): Add PAC_REG entry.
        * config/arm/arm.md (RA_AUTH_CODE): Define.

gcc/testsuite/ChangeLog:

2021-11-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * g++.target/arm/pac-1.C: New test.


###############     Attachment also inlined for ease of reply    ###############


diff --git a/gcc/config/arm/aout.h b/gcc/config/arm/aout.h
index 25a2812a663742893b928398b0d3948e97f1905b..c69e299e012f46c8d0711830125dbf2f6b2e93d7 100644
--- a/gcc/config/arm/aout.h
+++ b/gcc/config/arm/aout.h
@@ -74,7 +74,8 @@
   "wr8",   "wr9",   "wr10",  "wr11",                           \
   "wr12",  "wr13",  "wr14",  "wr15",                           \
   "wcgr0", "wcgr1", "wcgr2", "wcgr3",                          \
-  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0"         \
+  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0",                \
+  "ra_auth_code"                                               \
 }
 #endif

diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 8e6ef41f6b065217d1af3f4f1cb85b2d8fbd0dc0..f31944e85c9ab83501f156d138e2aea1bcb5b79d 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -815,7 +815,8 @@ extern const int arm_arch_cde_coproc_bits[];
         s16-s31       S  VFP variable (aka d8-d15).
         vfpcc           Not a real register.  Represents the VFP condition
                         code flags.
-       vpr             Used to represent MVE VPR predication.  */
+       vpr             Used to represent MVE VPR predication.
+       ra_auth_code    Pseudo register to save PAC.  */

 /* The stack backtrace structure is as follows:
   fp points to here:  |  save code pointer  |      [fp]
@@ -856,7 +857,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,             \
   1,1,1,1,                     \
   /* Specials.  */             \
-  1,1,1,1,1,1,1                        \
+  1,1,1,1,1,1,1,1              \
 }

 /* 1 for registers not available across function calls.
@@ -886,7 +887,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,             \
   1,1,1,1,                     \
   /* Specials.  */             \
-  1,1,1,1,1,1,1                        \
+  1,1,1,1,1,1,1,1              \
 }

 #ifndef SUBTARGET_CONDITIONAL_REGISTER_USAGE
@@ -1062,10 +1063,10 @@ extern const int arm_arch_cde_coproc_bits[];
    && (LAST_VFP_REGNUM - (REGNUM) >= 2 * (N) - 1))

 /* The number of hard registers is 16 ARM + 1 CC + 1 SFP + 1 AFP
-   + 1 APSRQ + 1 APSRGE + 1 VPR.  */
+   + 1 APSRQ + 1 APSRGE + 1 VPR + 1 Pseudo register to save PAC.  */
 /* Intel Wireless MMX Technology registers add 16 + 4 more.  */
 /* VFP (VFP3) adds 32 (64) + 1 VFPCC.  */
-#define FIRST_PSEUDO_REGISTER   107
+#define FIRST_PSEUDO_REGISTER   108

 #define DBX_REGISTER_NUMBER(REGNO) arm_dbx_register_number (REGNO)

@@ -1248,12 +1249,15 @@ extern int arm_regs_in_sequence[];
   CC_REGNUM, VFPCC_REGNUM,                     \
   FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM,    \
   SP_REGNUM, PC_REGNUM, APSRQ_REGNUM,          \
-  APSRGE_REGNUM, VPR_REGNUM                    \
+  APSRGE_REGNUM, VPR_REGNUM, RA_AUTH_CODE      \
 }

 #define IS_VPR_REGNUM(REGNUM) \
   ((REGNUM) == VPR_REGNUM)

+#define IS_PAC_Pseudo_REGNUM(REGNUM) \
+  ((REGNUM) == RA_AUTH_CODE)
+
 /* Use different register alloc ordering for Thumb.  */
 #define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()

@@ -1292,6 +1296,7 @@ enum reg_class
   SFP_REG,
   AFP_REG,
   VPR_REG,
+  PAC_REG,
   ALL_REGS,
   LIM_REG_CLASSES
 };
@@ -1321,6 +1326,7 @@ enum reg_class
   "SFP_REG",           \
   "AFP_REG",           \
   "VPR_REG",           \
+  "PAC_REG",           \
   "ALL_REGS"           \
 }

@@ -1349,6 +1355,7 @@ enum reg_class
   { 0x00000000, 0x00000000, 0x00000000, 0x00000040 }, /* SFP_REG */    \
   { 0x00000000, 0x00000000, 0x00000000, 0x00000080 }, /* AFP_REG */    \
   { 0x00000000, 0x00000000, 0x00000000, 0x00000400 }, /* VPR_REG.  */  \
+  { 0x00000000, 0x00000000, 0x00000000, 0x00000800 }, /* PAC_REG.  */  \
   { 0xFFFF7FFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0000000F }  /* ALL_REGS.  */ \
 }

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index a3e34747ba52840bd82f76df4a3f05704bd42ec1..966c49a3bf21de909dbab5abcac5d1d3b2af4262 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -22000,7 +22000,9 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
     {
       if (mask & (1 << i))
         {
-         reg = gen_rtx_REG (SImode, i);
+         rtx reg1 = reg = gen_rtx_REG (SImode, i);
+         if (arm_pac_enabled_for_curr_function_p () && i == IP_REGNUM)
+           reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);

           XVECEXP (par, 0, 0)
             = gen_rtx_SET (gen_frame_mem
@@ -22018,7 +22020,7 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
           if (dwarf_regs_mask & (1 << i))
             {
               tmp = gen_rtx_SET (gen_frame_mem (SImode, stack_pointer_rtx),
-                                reg);
+                                reg1);
               RTX_FRAME_RELATED_P (tmp) = 1;
               XVECEXP (dwarf, 0, dwarf_par_index++) = tmp;
             }
@@ -23505,7 +23507,10 @@ arm_expand_prologue (void)
     saved_regs += arm_save_coproc_regs ();

   if (arm_pac_enabled_for_curr_function_p ())
-      emit_multi_reg_push (1 << IP_REGNUM, 1 << IP_REGNUM);
+    {
+      insn = emit_multi_reg_push (1 << IP_REGNUM, 1 << IP_REGNUM);
+      RTX_FRAME_RELATED_P (insn) = 1;
+    }

   if (frame_pointer_needed && TARGET_ARM)
     {
@@ -25435,6 +25440,9 @@ arm_regno_class (int regno)
   if (IS_VPR_REGNUM (regno))
     return VPR_REG;

+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return PAC_REG;
+
   if (TARGET_THUMB1)
     {
       if (regno == STACK_POINTER_REGNUM)
@@ -29429,6 +29437,9 @@ arm_dbx_register_number (unsigned int regno)
   if (IS_IWMMXT_REGNUM (regno))
     return 112 + regno - FIRST_IWMMXT_REGNUM;

+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return 143;
+
   return DWARF_FRAME_REGISTERS;
 }

@@ -29550,6 +29561,11 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
       reg_size = 8;
       fprintf (out_file, "\t.vsave {");
     }
+  else if (IS_PAC_Pseudo_REGNUM (reg))
+    {
+      reg_size = 4;
+      fprintf (out_file, "\t.save {");
+    }
   else
     /* Unknown register type.  */
     gcc_unreachable ();
@@ -29579,6 +29595,8 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
          double precision register names.  */
       if (IS_VFP_REGNUM (reg))
         asm_fprintf (out_file, "d%d", (reg - FIRST_VFP_REGNUM) / 2);
+      else if (IS_PAC_Pseudo_REGNUM (reg))
+       asm_fprintf (asm_out_file, "ra_auth_code");
       else
         asm_fprintf (out_file, "%r", reg);

@@ -30447,7 +30465,10 @@ arm_conditional_register_usage (void)
     }

   if (TARGET_HAVE_PACBTI)
-    call_used_regs[IP_REGNUM] = 1;
+    {
+      call_used_regs[IP_REGNUM] = 1;
+      fixed_regs[RA_AUTH_CODE] = 0;
+    }

   /* The Q and GE bits are only accessed via special ACLE patterns.  */
   CLEAR_HARD_REG_BIT (operand_reg_set, APSRQ_REGNUM);
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 564170dc4500c2c5d961c9a19dd86a31416dc965..f27dc3f9041d8b32e7ad750c39143a6764156fe9 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -42,6 +42,7 @@
    (APSRQ_REGNUM    104)       ; Q bit pseudo register
    (APSRGE_REGNUM   105)       ; GE bits pseudo register
    (VPR_REGNUM      106)       ; Vector Predication Register - MVE register.
+   (RA_AUTH_CODE    107)       ; Pseudo register to save PAC.
   ]
 )
 ;; 3rd operand to select_dominance_cc_mode
diff --git a/gcc/testsuite/g++.target/arm/pac-1.C b/gcc/testsuite/g++.target/arm/pac-1.C
new file mode 100644
index 0000000000000000000000000000000000000000..d33c860f1e368581dd9c3552a7201c7932b8560f
--- /dev/null
+++ b/gcc/testsuite/g++.target/arm/pac-1.C
@@ -0,0 +1,32 @@
+/* Check that GCC does .save and .cfi_offset directives with RA_AUTH_CODE pseudo hard-register.  */
+/* { dg-do compile } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-marm" "-mcpu=*" } } */
+/* { dg-options "-O2 -march=armv8.1-m.main -mbranch-protection=pac-ret+leaf+bti -mthumb -mfloat-abi=soft --save-temps -g" } */
+
+__attribute__((noinline)) void
+fn1 (int a, int b, int c)
+{
+  if (a != b + c)
+    __builtin_abort ();
+  else
+    throw b+c;
+}
+
+int main ()
+{
+  int a = 120;
+  try
+    {
+      fn1 (a, 40, 80);
+    }
+  catch (int x)
+    {
+      if (x != a)
+        __builtin_abort ();
+      else
+       return 0;
+    }
+}
+
+/* { dg-final { scan-assembler "\.save \{ra_auth_code\}" } } */
+/* { dg-final { scan-assembler "\.cfi_offset 143, \-8" } } */


^ permalink raw reply	[flat|nested] 5+ messages in thread

* [PATCH v2][GCC] arm: Add support for dwarf debug directives and pseudo hard-register for PAC feature.
@ 2021-11-12 18:02 Srinath Parvathaneni
  2021-12-13 10:44 ` Srinath Parvathaneni
  0 siblings, 1 reply; 5+ messages in thread
From: Srinath Parvathaneni @ 2021-11-12 18:02 UTC (permalink / raw)
  To: gcc-patches; +Cc: Kyrylo.Tkachov, Richard.Earnshaw, Tejas.Belagod

[-- Attachment #1: Type: text/plain, Size: 9673 bytes --]

Hello,

This patch teaches the DWARF support in gcc about RA_AUTH_CODE pseudo hard-register and also 
.save {ra_auth_code} and .cfi_offset ra_auth_code <offset> dwarf directives for the PAC feature
in Armv8.1-M architecture.

RA_AUTH_CODE register number is 107 and it's dwarf register number is 143.

When compiled with "arm-none-eabi-gcc -O2  -mthumb -march=armv8.1-m.main+pacbti -S -fasynchronous-unwind-tables -g"
command line options, the directives supported in this patch looks like below:

        ...
        push    {ip}
        .save {ra_auth_code}
        .cfi_def_cfa_offset 8
        .cfi_offset 143, -8
        ...

This patch can be committed after the patch at https://gcc.gnu.org/pipermail/gcc-patches/2021-November/583407.html
is committed.

Regression tested on arm-none-eabi target and found no regressions.

Ok for master?

Regards,
Srinath.

gcc/ChangeLog:

2021-11-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * config/arm/aout.h (ra_auth_code): Add to enum.
        * config/arm/arm.c (emit_multi_reg_push): Add RA_AUTH_CODE register to
        dwarf frame expression instead of IP_REGNUM.
        (arm_expand_prologue): Mark as frame related insn.
        (arm_regno_class): Check for pac pseudo reigster.
        (arm_dbx_register_number): Assign ra_auth_code register number in dwarf.
        (arm_unwind_emit_sequence): Print .save directive with ra_auth_code
        register.
        (arm_conditional_register_usage): Mark ra_auth_code in fixed reigsters.
        * config/arm/arm.h (FIRST_PSEUDO_REGISTER): Modify.
        (IS_PAC_Pseudo_REGNUM): Define.
        (enum reg_class): Add PAC_REG entry.
        * config/arm/arm.md (RA_AUTH_CODE): Define.

gcc/testsuite/ChangeLog:

2021-11-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

        * g++.target/arm/pac-1.C: New test.


###############     Attachment also inlined for ease of reply    ###############


diff --git a/gcc/config/arm/aout.h b/gcc/config/arm/aout.h
index 25a2812a663742893b928398b0d3948e97f1905b..c69e299e012f46c8d0711830125dbf2f6b2e93d7 100644
--- a/gcc/config/arm/aout.h
+++ b/gcc/config/arm/aout.h
@@ -74,7 +74,8 @@
   "wr8",   "wr9",   "wr10",  "wr11",				\
   "wr12",  "wr13",  "wr14",  "wr15",				\
   "wcgr0", "wcgr1", "wcgr2", "wcgr3",				\
-  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0"		\
+  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0",		\
+  "ra_auth_code"						\
 }
 #endif
 
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 8e6ef41f6b065217d1af3f4f1cb85b2d8fbd0dc0..f31944e85c9ab83501f156d138e2aea1bcb5b79d 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -815,7 +815,8 @@ extern const int arm_arch_cde_coproc_bits[];
 	s16-s31	      S	VFP variable (aka d8-d15).
 	vfpcc		Not a real register.  Represents the VFP condition
 			code flags.
-	vpr		Used to represent MVE VPR predication.  */
+	vpr		Used to represent MVE VPR predication.
+	ra_auth_code	Pseudo register to save PAC.  */
 
 /* The stack backtrace structure is as follows:
   fp points to here:  |  save code pointer  |      [fp]
@@ -856,7 +857,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,		\
   1,1,1,1,			\
   /* Specials.  */		\
-  1,1,1,1,1,1,1			\
+  1,1,1,1,1,1,1,1		\
 }
 
 /* 1 for registers not available across function calls.
@@ -886,7 +887,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,		\
   1,1,1,1,			\
   /* Specials.  */		\
-  1,1,1,1,1,1,1			\
+  1,1,1,1,1,1,1,1		\
 }
 
 #ifndef SUBTARGET_CONDITIONAL_REGISTER_USAGE
@@ -1062,10 +1063,10 @@ extern const int arm_arch_cde_coproc_bits[];
    && (LAST_VFP_REGNUM - (REGNUM) >= 2 * (N) - 1))
 
 /* The number of hard registers is 16 ARM + 1 CC + 1 SFP + 1 AFP
-   + 1 APSRQ + 1 APSRGE + 1 VPR.  */
+   + 1 APSRQ + 1 APSRGE + 1 VPR + 1 Pseudo register to save PAC.  */
 /* Intel Wireless MMX Technology registers add 16 + 4 more.  */
 /* VFP (VFP3) adds 32 (64) + 1 VFPCC.  */
-#define FIRST_PSEUDO_REGISTER   107
+#define FIRST_PSEUDO_REGISTER   108
 
 #define DBX_REGISTER_NUMBER(REGNO) arm_dbx_register_number (REGNO)
 
@@ -1248,12 +1249,15 @@ extern int arm_regs_in_sequence[];
   CC_REGNUM, VFPCC_REGNUM,			\
   FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM,	\
   SP_REGNUM, PC_REGNUM, APSRQ_REGNUM,		\
-  APSRGE_REGNUM, VPR_REGNUM			\
+  APSRGE_REGNUM, VPR_REGNUM, RA_AUTH_CODE	\
 }
 
 #define IS_VPR_REGNUM(REGNUM) \
   ((REGNUM) == VPR_REGNUM)
 
+#define IS_PAC_Pseudo_REGNUM(REGNUM) \
+  ((REGNUM) == RA_AUTH_CODE)
+
 /* Use different register alloc ordering for Thumb.  */
 #define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()
 
@@ -1292,6 +1296,7 @@ enum reg_class
   SFP_REG,
   AFP_REG,
   VPR_REG,
+  PAC_REG,
   ALL_REGS,
   LIM_REG_CLASSES
 };
@@ -1321,6 +1326,7 @@ enum reg_class
   "SFP_REG",		\
   "AFP_REG",		\
   "VPR_REG",		\
+  "PAC_REG",		\
   "ALL_REGS"		\
 }
 
@@ -1349,6 +1355,7 @@ enum reg_class
   { 0x00000000, 0x00000000, 0x00000000, 0x00000040 }, /* SFP_REG */	\
   { 0x00000000, 0x00000000, 0x00000000, 0x00000080 }, /* AFP_REG */	\
   { 0x00000000, 0x00000000, 0x00000000, 0x00000400 }, /* VPR_REG.  */	\
+  { 0x00000000, 0x00000000, 0x00000000, 0x00000800 }, /* PAC_REG.  */	\
   { 0xFFFF7FFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0000000F }  /* ALL_REGS.  */	\
 }
 
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index a3e34747ba52840bd82f76df4a3f05704bd42ec1..966c49a3bf21de909dbab5abcac5d1d3b2af4262 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -22000,7 +22000,9 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
     {
       if (mask & (1 << i))
 	{
-	  reg = gen_rtx_REG (SImode, i);
+	  rtx reg1 = reg = gen_rtx_REG (SImode, i);
+	  if (arm_pac_enabled_for_curr_function_p () && i == IP_REGNUM)
+	    reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
 
 	  XVECEXP (par, 0, 0)
 	    = gen_rtx_SET (gen_frame_mem
@@ -22018,7 +22020,7 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
 	  if (dwarf_regs_mask & (1 << i))
 	    {
 	      tmp = gen_rtx_SET (gen_frame_mem (SImode, stack_pointer_rtx),
-				 reg);
+				 reg1);
 	      RTX_FRAME_RELATED_P (tmp) = 1;
 	      XVECEXP (dwarf, 0, dwarf_par_index++) = tmp;
 	    }
@@ -23505,7 +23507,10 @@ arm_expand_prologue (void)
     saved_regs += arm_save_coproc_regs ();
 
   if (arm_pac_enabled_for_curr_function_p ())
-      emit_multi_reg_push (1 << IP_REGNUM, 1 << IP_REGNUM);
+    {
+      insn = emit_multi_reg_push (1 << IP_REGNUM, 1 << IP_REGNUM);
+      RTX_FRAME_RELATED_P (insn) = 1;
+    }
 
   if (frame_pointer_needed && TARGET_ARM)
     {
@@ -25435,6 +25440,9 @@ arm_regno_class (int regno)
   if (IS_VPR_REGNUM (regno))
     return VPR_REG;
 
+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return PAC_REG;
+
   if (TARGET_THUMB1)
     {
       if (regno == STACK_POINTER_REGNUM)
@@ -29429,6 +29437,9 @@ arm_dbx_register_number (unsigned int regno)
   if (IS_IWMMXT_REGNUM (regno))
     return 112 + regno - FIRST_IWMMXT_REGNUM;
 
+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return 143;
+
   return DWARF_FRAME_REGISTERS;
 }
 
@@ -29550,6 +29561,11 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
       reg_size = 8;
       fprintf (out_file, "\t.vsave {");
     }
+  else if (IS_PAC_Pseudo_REGNUM (reg))
+    {
+      reg_size = 4;
+      fprintf (out_file, "\t.save {");
+    }
   else
     /* Unknown register type.  */
     gcc_unreachable ();
@@ -29579,6 +29595,8 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
 	 double precision register names.  */
       if (IS_VFP_REGNUM (reg))
 	asm_fprintf (out_file, "d%d", (reg - FIRST_VFP_REGNUM) / 2);
+      else if (IS_PAC_Pseudo_REGNUM (reg))
+	asm_fprintf (asm_out_file, "ra_auth_code");
       else
 	asm_fprintf (out_file, "%r", reg);
 
@@ -30447,7 +30465,10 @@ arm_conditional_register_usage (void)
     }
 
   if (TARGET_HAVE_PACBTI)
-    call_used_regs[IP_REGNUM] = 1;
+    {
+      call_used_regs[IP_REGNUM] = 1;
+      fixed_regs[RA_AUTH_CODE] = 0;
+    }
 
   /* The Q and GE bits are only accessed via special ACLE patterns.  */
   CLEAR_HARD_REG_BIT (operand_reg_set, APSRQ_REGNUM);
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 564170dc4500c2c5d961c9a19dd86a31416dc965..f27dc3f9041d8b32e7ad750c39143a6764156fe9 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -42,6 +42,7 @@
    (APSRQ_REGNUM    104)	; Q bit pseudo register
    (APSRGE_REGNUM   105)	; GE bits pseudo register
    (VPR_REGNUM      106)	; Vector Predication Register - MVE register.
+   (RA_AUTH_CODE    107)	; Pseudo register to save PAC.
   ]
 )
 ;; 3rd operand to select_dominance_cc_mode
diff --git a/gcc/testsuite/g++.target/arm/pac-1.C b/gcc/testsuite/g++.target/arm/pac-1.C
new file mode 100644
index 0000000000000000000000000000000000000000..d33c860f1e368581dd9c3552a7201c7932b8560f
--- /dev/null
+++ b/gcc/testsuite/g++.target/arm/pac-1.C
@@ -0,0 +1,32 @@
+/* Check that GCC does .save and .cfi_offset directives with RA_AUTH_CODE pseudo hard-register.  */
+/* { dg-do compile } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-marm" "-mcpu=*" } } */
+/* { dg-options "-O2 -march=armv8.1-m.main -mbranch-protection=pac-ret+leaf+bti -mthumb -mfloat-abi=soft --save-temps -g" } */
+
+__attribute__((noinline)) void
+fn1 (int a, int b, int c)
+{
+  if (a != b + c)
+    __builtin_abort ();
+  else
+    throw b+c;
+}
+
+int main ()
+{
+  int a = 120;
+  try
+    {
+      fn1 (a, 40, 80);
+    }
+  catch (int x)
+    {
+      if (x != a)
+        __builtin_abort ();
+      else
+	return 0;
+    }
+}
+
+/* { dg-final { scan-assembler "\.save \{ra_auth_code\}" } } */
+/* { dg-final { scan-assembler "\.cfi_offset 143, \-8" } } */


[-- Attachment #2: rb14831.patch --]
[-- Type: text/plain, Size: 7746 bytes --]

diff --git a/gcc/config/arm/aout.h b/gcc/config/arm/aout.h
index 25a2812a663742893b928398b0d3948e97f1905b..c69e299e012f46c8d0711830125dbf2f6b2e93d7 100644
--- a/gcc/config/arm/aout.h
+++ b/gcc/config/arm/aout.h
@@ -74,7 +74,8 @@
   "wr8",   "wr9",   "wr10",  "wr11",				\
   "wr12",  "wr13",  "wr14",  "wr15",				\
   "wcgr0", "wcgr1", "wcgr2", "wcgr3",				\
-  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0"		\
+  "cc", "vfpcc", "sfp", "afp", "apsrq", "apsrge", "p0",		\
+  "ra_auth_code"						\
 }
 #endif
 
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 8e6ef41f6b065217d1af3f4f1cb85b2d8fbd0dc0..f31944e85c9ab83501f156d138e2aea1bcb5b79d 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -815,7 +815,8 @@ extern const int arm_arch_cde_coproc_bits[];
 	s16-s31	      S	VFP variable (aka d8-d15).
 	vfpcc		Not a real register.  Represents the VFP condition
 			code flags.
-	vpr		Used to represent MVE VPR predication.  */
+	vpr		Used to represent MVE VPR predication.
+	ra_auth_code	Pseudo register to save PAC.  */
 
 /* The stack backtrace structure is as follows:
   fp points to here:  |  save code pointer  |      [fp]
@@ -856,7 +857,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,		\
   1,1,1,1,			\
   /* Specials.  */		\
-  1,1,1,1,1,1,1			\
+  1,1,1,1,1,1,1,1		\
 }
 
 /* 1 for registers not available across function calls.
@@ -886,7 +887,7 @@ extern const int arm_arch_cde_coproc_bits[];
   1,1,1,1,1,1,1,1,		\
   1,1,1,1,			\
   /* Specials.  */		\
-  1,1,1,1,1,1,1			\
+  1,1,1,1,1,1,1,1		\
 }
 
 #ifndef SUBTARGET_CONDITIONAL_REGISTER_USAGE
@@ -1062,10 +1063,10 @@ extern const int arm_arch_cde_coproc_bits[];
    && (LAST_VFP_REGNUM - (REGNUM) >= 2 * (N) - 1))
 
 /* The number of hard registers is 16 ARM + 1 CC + 1 SFP + 1 AFP
-   + 1 APSRQ + 1 APSRGE + 1 VPR.  */
+   + 1 APSRQ + 1 APSRGE + 1 VPR + 1 Pseudo register to save PAC.  */
 /* Intel Wireless MMX Technology registers add 16 + 4 more.  */
 /* VFP (VFP3) adds 32 (64) + 1 VFPCC.  */
-#define FIRST_PSEUDO_REGISTER   107
+#define FIRST_PSEUDO_REGISTER   108
 
 #define DBX_REGISTER_NUMBER(REGNO) arm_dbx_register_number (REGNO)
 
@@ -1248,12 +1249,15 @@ extern int arm_regs_in_sequence[];
   CC_REGNUM, VFPCC_REGNUM,			\
   FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM,	\
   SP_REGNUM, PC_REGNUM, APSRQ_REGNUM,		\
-  APSRGE_REGNUM, VPR_REGNUM			\
+  APSRGE_REGNUM, VPR_REGNUM, RA_AUTH_CODE	\
 }
 
 #define IS_VPR_REGNUM(REGNUM) \
   ((REGNUM) == VPR_REGNUM)
 
+#define IS_PAC_Pseudo_REGNUM(REGNUM) \
+  ((REGNUM) == RA_AUTH_CODE)
+
 /* Use different register alloc ordering for Thumb.  */
 #define ADJUST_REG_ALLOC_ORDER arm_order_regs_for_local_alloc ()
 
@@ -1292,6 +1296,7 @@ enum reg_class
   SFP_REG,
   AFP_REG,
   VPR_REG,
+  PAC_REG,
   ALL_REGS,
   LIM_REG_CLASSES
 };
@@ -1321,6 +1326,7 @@ enum reg_class
   "SFP_REG",		\
   "AFP_REG",		\
   "VPR_REG",		\
+  "PAC_REG",		\
   "ALL_REGS"		\
 }
 
@@ -1349,6 +1355,7 @@ enum reg_class
   { 0x00000000, 0x00000000, 0x00000000, 0x00000040 }, /* SFP_REG */	\
   { 0x00000000, 0x00000000, 0x00000000, 0x00000080 }, /* AFP_REG */	\
   { 0x00000000, 0x00000000, 0x00000000, 0x00000400 }, /* VPR_REG.  */	\
+  { 0x00000000, 0x00000000, 0x00000000, 0x00000800 }, /* PAC_REG.  */	\
   { 0xFFFF7FFF, 0xFFFFFFFF, 0xFFFFFFFF, 0x0000000F }  /* ALL_REGS.  */	\
 }
 
diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index a3e34747ba52840bd82f76df4a3f05704bd42ec1..966c49a3bf21de909dbab5abcac5d1d3b2af4262 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -22000,7 +22000,9 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
     {
       if (mask & (1 << i))
 	{
-	  reg = gen_rtx_REG (SImode, i);
+	  rtx reg1 = reg = gen_rtx_REG (SImode, i);
+	  if (arm_pac_enabled_for_curr_function_p () && i == IP_REGNUM)
+	    reg1 = gen_rtx_REG (SImode, RA_AUTH_CODE);
 
 	  XVECEXP (par, 0, 0)
 	    = gen_rtx_SET (gen_frame_mem
@@ -22018,7 +22020,7 @@ emit_multi_reg_push (unsigned long mask, unsigned long dwarf_regs_mask)
 	  if (dwarf_regs_mask & (1 << i))
 	    {
 	      tmp = gen_rtx_SET (gen_frame_mem (SImode, stack_pointer_rtx),
-				 reg);
+				 reg1);
 	      RTX_FRAME_RELATED_P (tmp) = 1;
 	      XVECEXP (dwarf, 0, dwarf_par_index++) = tmp;
 	    }
@@ -23505,7 +23507,10 @@ arm_expand_prologue (void)
     saved_regs += arm_save_coproc_regs ();
 
   if (arm_pac_enabled_for_curr_function_p ())
-      emit_multi_reg_push (1 << IP_REGNUM, 1 << IP_REGNUM);
+    {
+      insn = emit_multi_reg_push (1 << IP_REGNUM, 1 << IP_REGNUM);
+      RTX_FRAME_RELATED_P (insn) = 1;
+    }
 
   if (frame_pointer_needed && TARGET_ARM)
     {
@@ -25435,6 +25440,9 @@ arm_regno_class (int regno)
   if (IS_VPR_REGNUM (regno))
     return VPR_REG;
 
+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return PAC_REG;
+
   if (TARGET_THUMB1)
     {
       if (regno == STACK_POINTER_REGNUM)
@@ -29429,6 +29437,9 @@ arm_dbx_register_number (unsigned int regno)
   if (IS_IWMMXT_REGNUM (regno))
     return 112 + regno - FIRST_IWMMXT_REGNUM;
 
+  if (IS_PAC_Pseudo_REGNUM (regno))
+    return 143;
+
   return DWARF_FRAME_REGISTERS;
 }
 
@@ -29550,6 +29561,11 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
       reg_size = 8;
       fprintf (out_file, "\t.vsave {");
     }
+  else if (IS_PAC_Pseudo_REGNUM (reg))
+    {
+      reg_size = 4;
+      fprintf (out_file, "\t.save {");
+    }
   else
     /* Unknown register type.  */
     gcc_unreachable ();
@@ -29579,6 +29595,8 @@ arm_unwind_emit_sequence (FILE * out_file, rtx p)
 	 double precision register names.  */
       if (IS_VFP_REGNUM (reg))
 	asm_fprintf (out_file, "d%d", (reg - FIRST_VFP_REGNUM) / 2);
+      else if (IS_PAC_Pseudo_REGNUM (reg))
+	asm_fprintf (asm_out_file, "ra_auth_code");
       else
 	asm_fprintf (out_file, "%r", reg);
 
@@ -30447,7 +30465,10 @@ arm_conditional_register_usage (void)
     }
 
   if (TARGET_HAVE_PACBTI)
-    call_used_regs[IP_REGNUM] = 1;
+    {
+      call_used_regs[IP_REGNUM] = 1;
+      fixed_regs[RA_AUTH_CODE] = 0;
+    }
 
   /* The Q and GE bits are only accessed via special ACLE patterns.  */
   CLEAR_HARD_REG_BIT (operand_reg_set, APSRQ_REGNUM);
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 564170dc4500c2c5d961c9a19dd86a31416dc965..f27dc3f9041d8b32e7ad750c39143a6764156fe9 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -42,6 +42,7 @@
    (APSRQ_REGNUM    104)	; Q bit pseudo register
    (APSRGE_REGNUM   105)	; GE bits pseudo register
    (VPR_REGNUM      106)	; Vector Predication Register - MVE register.
+   (RA_AUTH_CODE    107)	; Pseudo register to save PAC.
   ]
 )
 ;; 3rd operand to select_dominance_cc_mode
diff --git a/gcc/testsuite/g++.target/arm/pac-1.C b/gcc/testsuite/g++.target/arm/pac-1.C
new file mode 100644
index 0000000000000000000000000000000000000000..d33c860f1e368581dd9c3552a7201c7932b8560f
--- /dev/null
+++ b/gcc/testsuite/g++.target/arm/pac-1.C
@@ -0,0 +1,32 @@
+/* Check that GCC does .save and .cfi_offset directives with RA_AUTH_CODE pseudo hard-register.  */
+/* { dg-do compile } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-marm" "-mcpu=*" } } */
+/* { dg-options "-O2 -march=armv8.1-m.main -mbranch-protection=pac-ret+leaf+bti -mthumb -mfloat-abi=soft --save-temps -g" } */
+
+__attribute__((noinline)) void
+fn1 (int a, int b, int c)
+{
+  if (a != b + c)
+    __builtin_abort ();
+  else
+    throw b+c;
+}
+
+int main ()
+{
+  int a = 120;
+  try
+    {
+      fn1 (a, 40, 80);
+    }
+  catch (int x)
+    {
+      if (x != a)
+        __builtin_abort ();
+      else
+	return 0;
+    }
+}
+
+/* { dg-final { scan-assembler "\.save \{ra_auth_code\}" } } */
+/* { dg-final { scan-assembler "\.cfi_offset 143, \-8" } } */


^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2022-07-04 18:33 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2022-05-05 11:02 [PATCH v2][GCC] arm: Add support for dwarf debug directives and pseudo hard-register for PAC feature Srinath Parvathaneni
2022-07-04 18:33 ` Srinath Parvathaneni
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2021-11-12 18:02 Srinath Parvathaneni
2021-12-13 10:44 ` Srinath Parvathaneni
2022-01-12 13:45   ` Srinath Parvathaneni

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