[PATCH] [PR target/96350]Force ENDBR immediate into memory to avoid fake ENDBR opcode.

[Hongtao Liu <crazylht@gmail.com>]

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Hi:
  The issue is described in the bugzilla.
  Bootstrap is ok, regression test for i386/x86-64 backend is ok.
  Ok for trunk?

ChangeLog
gcc/
        PR target/96350
        * config/i386/i386.c (ix86_legitimate_constant_p): Return
        false for ENDBR immediate.
        (ix86_legitimate_address_p): Ditto.
        * config/i386/predicated.md
        (x86_64_immediate_operand): Exclude ENDBR immediate.
        (x86_64_zext_immediate_operand): Ditto.
        (x86_64_dwzext_immediate_operand): Ditto.
        (ix86_not_endbr_immediate_operand): New predicate.

gcc/testsuite
        * gcc.target/i386/endbr_immediate.c: New test.

-- 
BR,
Hongtao

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From 073517f01e8872e23b2dda5e6e25142ad4cfe274 Mon Sep 17 00:00:00 2001
From: liuhongt <hongtao.liu@intel.com>
Date: Tue, 4 Aug 2020 10:00:13 +0800
Subject: [PATCH] Force ENDBR immediate into memory.

gcc/
	PR target/96350
	* config/i386/i386.c (ix86_legitimate_constant_p): Return
	false for ENDBR immediate.
	(ix86_legitimate_address_p): Ditto.
	* config/i386/predicated.md
	(x86_64_immediate_operand): Exclude ENDBR immediate.
	(x86_64_zext_immediate_operand): Ditto.
	(x86_64_dwzext_immediate_operand): Ditto.
	(ix86_not_endbr_immediate_operand): New predicate.

gcc/testsuite
	* gcc.target/i386/endbr_immediate.c: New test.
---
 gcc/config/i386/i386.c                        |   5 +-
 gcc/config/i386/predicates.md                 |  33 +++
 .../gcc.target/i386/endbr_immediate.c         | 198 ++++++++++++++++++
 3 files changed, 235 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/endbr_immediate.c

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 8ea6a4d7ea7..228efb60a72 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -10080,7 +10080,7 @@ ix86_legitimate_constant_p (machine_mode mode, rtx x)
     }
 
   /* Otherwise we handle everything else in the move patterns.  */
-  return true;
+  return ix86_not_endbr_immediate_operand (x, VOIDmode);
 }
 
 /* Determine if it's legal to put X into the constant pool.  This
@@ -10568,6 +10568,9 @@ ix86_legitimate_address_p (machine_mode, rtx addr, bool strict)
 	return false;
     }
 
+  if (disp && !ix86_not_endbr_immediate_operand (disp, VOIDmode))
+    return false;
+
   /* Everything looks valid.  */
   return true;
 }
diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md
index 07e69d555c0..47e65892d94 100644
--- a/gcc/config/i386/predicates.md
+++ b/gcc/config/i386/predicates.md
@@ -130,10 +130,38 @@
 (define_predicate "symbol_operand"
   (match_code "symbol_ref"))
 
+;; Return true if VALUE isn't an ENDBR opcode in immediate field.
+(define_predicate "ix86_not_endbr_immediate_operand"
+  (match_test "1")
+{
+  if ((flag_cf_protection & CF_BRANCH)
+      && CONST_INT_P (op))
+     {
+       unsigned HOST_WIDE_INT imm = INTVAL (op);
+       if (!TARGET_64BIT || imm <= 0xffffffff)
+	 return imm != (TARGET_64BIT ? 0xfa1e0ff3 : 0xfb1e0ff3);
+
+       /* NB: Encoding is byte based.  */
+       do
+	 {
+	  if ((0xffffffff & imm) == 0xfa1e0ff3)
+	    return false;
+	  imm >>= 8;
+	 }
+       while (imm > 0xffffffff);
+
+       return true;
+      }
+  return true;
+})
+
 ;; Return true if VALUE can be stored in a sign extended immediate field.
 (define_predicate "x86_64_immediate_operand"
   (match_code "const_int,symbol_ref,label_ref,const")
 {
+  if (!ix86_not_endbr_immediate_operand (op, VOIDmode))
+    return false;
+
   if (!TARGET_64BIT)
     return immediate_operand (op, mode);
 
@@ -260,6 +288,9 @@
 (define_predicate "x86_64_zext_immediate_operand"
   (match_code "const_int,symbol_ref,label_ref,const")
 {
+  if (!ix86_not_endbr_immediate_operand (op, VOIDmode))
+    return false;
+
   switch (GET_CODE (op))
     {
     case CONST_INT:
@@ -374,6 +405,8 @@
 (define_predicate "x86_64_dwzext_immediate_operand"
   (match_code "const_int,const_wide_int")
 {
+  if (!ix86_not_endbr_immediate_operand (op, VOIDmode))
+    return false;
   switch (GET_CODE (op))
     {
     case CONST_INT:
diff --git a/gcc/testsuite/gcc.target/i386/endbr_immediate.c b/gcc/testsuite/gcc.target/i386/endbr_immediate.c
new file mode 100644
index 00000000000..3015512aa0e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/endbr_immediate.c
@@ -0,0 +1,198 @@
+/* PR target/96350 */
+/* { dg-do compile } */
+/* { dg-options "-fcf-protection -O2" } */
+/* { dg-final { scan-assembler-not "$-81915917" { target { ia32 } } } } */
+/* { dg-final { scan-assembler-not "$-98693133" { target { ! ia32 } } } } *
+/* { dg-final { scan-assembler-not "$-423883778574778368" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "\[ \t\]*-81915917" { target { ia32 } } } } */
+/* { dg-final { scan-assembler "\[ \t\]*-98693133" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "\[ \t\]*-423883778574778368" { target { ! ia32 } } } } */
+
+
+#ifdef __x86_64__
+#define ENDBR_IMMEDIATE 0xfa1e0ff3
+#define EXTEND_ENDBR_IMMEDIATE 0xfa1e0ff300000000
+#else
+#define ENDBR_IMMEDIATE 0xfb1e0ff3
+#define EXTEND_ENDBR_IMMEDIATE 0xfffb1e0ff300
+#endif
+
+int
+foo (int a)
+{
+  return a + ENDBR_IMMEDIATE;
+}
+
+int
+foo2 (int a)
+{
+  return a - ENDBR_IMMEDIATE;
+}
+
+int
+foo3 (int a)
+{
+  return a * ENDBR_IMMEDIATE;
+}
+
+int
+foo4 (int a)
+{
+  return a | ENDBR_IMMEDIATE;
+}
+
+int
+foo5 (int a)
+{
+  return a ^ ENDBR_IMMEDIATE;
+}
+
+int
+foo6 (int a)
+{
+  return a & ENDBR_IMMEDIATE;
+}
+
+int
+foo7 (int a)
+{
+  return a > ENDBR_IMMEDIATE;
+}
+
+int
+foo8 (int a)
+{
+  return ENDBR_IMMEDIATE;
+}
+
+int
+foo9 (int* p)
+{
+  return *(p + ENDBR_IMMEDIATE);
+}
+
+int
+foo10 (int* p)
+{
+  return *(int*) ENDBR_IMMEDIATE;
+}
+
+long long
+foo11 (long long a)
+{
+  return a + EXTEND_ENDBR_IMMEDIATE;
+}
+
+long long
+foo12 (long long a)
+{
+  return a - EXTEND_ENDBR_IMMEDIATE;
+}
+
+long long
+foo13 (long long a)
+{
+  return a * EXTEND_ENDBR_IMMEDIATE;
+}
+
+long long
+foo14 (long long a)
+{
+  return a | EXTEND_ENDBR_IMMEDIATE;
+}
+
+long long
+foo15 (long long a)
+{
+  return a ^ EXTEND_ENDBR_IMMEDIATE;
+}
+
+long long
+foo16 (long long a)
+{
+  return a & EXTEND_ENDBR_IMMEDIATE;
+}
+
+long long
+foo17 (long long a)
+{
+  return a > EXTEND_ENDBR_IMMEDIATE;
+}
+
+long long
+foo18 (long long a)
+{
+  return EXTEND_ENDBR_IMMEDIATE;
+}
+
+long long
+foo19 (long long* p)
+{
+  return *(p + EXTEND_ENDBR_IMMEDIATE);
+}
+
+long long
+foo20 (long long* p)
+{
+  return *(long long*) EXTEND_ENDBR_IMMEDIATE;
+}
+
+long long
+foo21 (int a)
+{
+  return a + ENDBR_IMMEDIATE;
+}
+
+long long
+foo22 (int a)
+{
+  return a - ENDBR_IMMEDIATE;
+}
+
+long long
+foo23 (long long a)
+{
+  return a * ENDBR_IMMEDIATE;
+}
+
+long long
+foo24 (int a)
+{
+  return a | ENDBR_IMMEDIATE;
+}
+
+long long
+foo25 (int a)
+{
+  return a ^ ENDBR_IMMEDIATE;
+}
+
+long long
+foo26 (int a)
+{
+  return a & ENDBR_IMMEDIATE;
+}
+
+long long
+foo27 (int a)
+{
+  return a > ENDBR_IMMEDIATE;
+}
+
+long long
+foo28 (int a)
+{
+  return ENDBR_IMMEDIATE;
+}
+
+long long
+foo29 (int* p)
+{
+  return *(p + ENDBR_IMMEDIATE);
+}
+
+long long
+foo30 (int* p)
+{
+  return *(long long*) ENDBR_IMMEDIATE;
+}
-- 
2.18.1