x86: drop some stray/bogus DefaultSize

Insns permitting only GPR operands (and hence implicit sizing when
there's no suffix) don't ever have their DefaultSize attribute
inspected, so it shouldn't be there in the first place.

Additionally XBEGIN is like JMP, not CALL, and hence shouldn't be
converted to 32-bit operand size in .code16gcc mode. While the same is
true for SYSRET, it permitting more than one suffix makes it FLDENV-
like, and hence rather than dropping the attribute, for now add it to
the exclusion list to avoid it getting an operand size prefix emitted
in .code16gcc mode. (This will be dealt with later, perhaps together
with FLDENV and friends.)

4 files changed, 94 insertions, 9 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 45e8b8a..7307dc8 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,10 @@
+2019-12-04  Jan Beulich  <jbeulich@suse.com>
+
+	* config/tc-i386.c (process_suffix): Exclude SYSRET alongside
+	FLDENV et al.
+	* testsuite/gas/i386/general.s: Expand .code16gcc set of insns.
+	* testsuite/gas/i386/general.l: Adjust expectations.
+
 2019-11-22  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* as.c (flag_dwarf_cie_version): Change initial value to -1, and
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 120367d..64312d2 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -6311,7 +6311,9 @@ process_suffix (void)
   else if (i.tm.opcode_modifier.defaultsize
 	   && !i.suffix
 	   /* exclude fldenv/frstor/fsave/fstenv */
-	   && i.tm.opcode_modifier.no_ssuf)
+	   && i.tm.opcode_modifier.no_ssuf
+	   /* exclude sysret */
+	   && i.tm.base_opcode != 0x0f07)
     {
       if (stackop_size == LONG_MNEM_SUFFIX
 	  && i.tm.base_opcode == 0xcf)
diff --git a/gas/testsuite/gas/i386/general.l b/gas/testsuite/gas/i386/general.l
index ac17096..d5f74d1 100644
--- a/gas/testsuite/gas/i386/general.l
+++ b/gas/testsuite/gas/i386/general.l
@@ -31,6 +31,7 @@
 .*:143: Warning:.*
 .*:144: Warning:.*
 .*:178: Warning:.*
+.*:224: Warning:.*
    1                       	.psize 0
    2                       	.text
    3                       	#test jumps and calls
@@ -283,11 +284,49 @@
  217 022a 0FB6C8            		movzb	%al,%ecx
  218                       	
  219                       	.code16gcc
- 220                       	# Use 16-bit layout by default for fldenv.
- 221 022d 67D920            		fldenv	\(%eax\)
- 222 0230 67D920            		fldenvs	\(%eax\)
- 223 0233 6766D920          		fldenvl	\(%eax\)
- 224                       	
- 225                       		# Force a good alignment.
- 226 0237 00000000 00000000 		.p2align	4,0
- 226      00
+[ 	]*[1-9][0-9]*[ 	]*# Except for IRET use 32-bit implicit stack accesses by default.
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66E8FAFF FFFF[ 	]+call	\.
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66FF17[ 	]+call	\*\(%bx\)
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66C80000 00[ 	]+enter	\$0,\$0
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+CF[ 	]+iret
+.*Warning:.*16-bit.*iret.*
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66FF1F[ 	]+lcall	\*\(%bx\)
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+669A0000 00000000[ 	]+lcall	\$0,\$0
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66C9[ 	]+leave
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66CB[ 	]+lret
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66CA0000[ 	]+lret	\$0
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+666A00[ 	]+push	\$0
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66683412 0000[ 	]+push	\$0x1234
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66FF37[ 	]+push	\(%bx\)
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+6660[ 	]+pusha
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+669C[ 	]+pushf
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+668F07[ 	]+pop	\(%bx\)
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+6661[ 	]+popa
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+669D[ 	]+popf
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66C3[ 	]+ret
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+66C20000[ 	]+ret	\$0
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]*# However use 16-bit branches not accessing the stack by default.
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+77FE[ 	]+ja	\.
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+0F873012[ 	]+ja	\.\+0x1234
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+E3FE[ 	]+jcxz	\.
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+EBFE[ 	]+jmp	\.
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+E93112[ 	]+jmp	\.\+0x1234
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+FF27[ 	]+jmp	\*\(%bx\)
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+FF2F[ 	]+ljmp	\*\(%bx\)
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+EA000000 00[ 	]+ljmp	\$0,\$0
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+E2FE[ 	]+loop	\.
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+0F05[ 	]+syscall
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+0F34[ 	]+sysenter
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+0F35[ 	]+sysexit
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+0F07[ 	]+sysret
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+C7F8FCFF[ 	]+xbegin	\.
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]*# Use 16-bit layout by default for fldenv.
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+67D920[ 	]+fldenv	\(%eax\)
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+67D920[ 	]+fldenvs	\(%eax\)
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f]*[ 	]+6766D920[ 	]+fldenvl	\(%eax\)
+[ 	]*[1-9][0-9]*[ 	]*
+[ 	]*[1-9][0-9]*[ 	]*# Force a good alignment.
+[ 	]*[1-9][0-9]*[ 	]+[0-9a-f 	]+\.p2align	4,0
+#pass
diff --git a/gas/testsuite/gas/i386/general.s b/gas/testsuite/gas/i386/general.s
index e4b2530..add14fd 100644
--- a/gas/testsuite/gas/i386/general.s
+++ b/gas/testsuite/gas/i386/general.s
@@ -217,6 +217,43 @@
 	movzb	%al,%ecx
 
 .code16gcc
+# Except for IRET use 32-bit implicit stack accesses by default.
+	call	.
+	call	*(%bx)
+	enter	$0,$0
+	iret
+	lcall	*(%bx)
+	lcall	$0,$0
+	leave
+	lret
+	lret	$0
+	push	$0
+	push	$0x1234
+	push	(%bx)
+	pusha
+	pushf
+	pop	(%bx)
+	popa
+	popf
+	ret
+	ret	$0
+
+# However use 16-bit branches not accessing the stack by default.
+	ja	.
+	ja	.+0x1234
+	jcxz	.
+	jmp	.
+	jmp	.+0x1234
+	jmp	*(%bx)
+	ljmp	*(%bx)
+	ljmp	$0,$0
+	loop	.
+	syscall
+	sysenter
+	sysexit
+	sysret
+	xbegin	.
+
 # Use 16-bit layout by default for fldenv.
 	fldenv	(%eax)
 	fldenvs	(%eax)