i386: Issue a warning to IRET without suffix for .code16gcc

The .code16gcc directive to support 16-bit mode with 32-bit address.
For IRET without a suffix, generate 16-bit IRET with a warning to
return from an interrupt handler in 16-bit mode.

	PR gas/24485
	* config/tc-i386.c (process_suffix): Issue a warning to IRET
	without a suffix for .code16gcc.
	* testsuite/gas/i386/jump16.s: Add tests for iretX.
	* testsuite/gas/i386/jump16.d: Updated.
	* testsuite/gas/i386/jump16.e: New file.

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 2dd2cf38a46d7411c7d147f6f49771afd76a2de2..8a82fdecbe66ed885fc2767b0d1eab29bfa42319 100644 (file)
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,12 @@
+2019-05-02  H.J. Lu  <hongjiu.lu@intel.com>
+
+       PR gas/24485
+       * config/tc-i386.c (process_suffix): Issue a warning to IRET
+       without a suffix for .code16gcc.
+       * testsuite/gas/i386/jump16.s: Add tests for iretX.
+       * testsuite/gas/i386/jump16.d: Updated.
+       * testsuite/gas/i386/jump16.e: New file.
+
 2019-05-01  Sudakshina Das  <sudi.das@arm.com>
 
        * config/tc-aarch64.c (parse_operands): Add case for

diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 032b1d308115d3f8a95b0d1f8ba169011292a8e3..7159432f1330512b5a8f839e6fc05ed35ae89bf3 100644 (file)
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -6242,7 +6242,19 @@ process_suffix (void)
           /* exclude fldenv/frstor/fsave/fstenv */
           && i.tm.opcode_modifier.no_ssuf)
     {
-      i.suffix = stackop_size;
+      if (stackop_size == LONG_MNEM_SUFFIX
+         && i.tm.base_opcode == 0xcf)
+       {
+         /* stackop_size is set to LONG_MNEM_SUFFIX for the
+            .code16gcc directive to support 16-bit mode with
+            32-bit address.  For IRET without a suffix, generate
+            16-bit IRET (opcode 0xcf) to return from an interrupt
+            handler.  */
+         i.suffix = WORD_MNEM_SUFFIX;
+         as_warn (_("generating 16-bit `iret' for .code16gcc directive"));
+       }
+      else
+       i.suffix = stackop_size;
     }
   else if (intel_syntax
           && !i.suffix
@@ -6352,13 +6364,7 @@ process_suffix (void)
            if (!add_prefix (ADDR_PREFIX_OPCODE))
              return 0;
        }
-      /* stackop_size is set to LONG_MNEM_SUFFIX for the .code16gcc
-        directive to support 16bit mode with 32-bit address.  Since
-        IRET (opcode 0xcf) in 16bit mode returns from an interrupt
-        in 16bit mode, we shouldn't add DATA_PREFIX_OPCODE here.  */
       else if (i.suffix != QWORD_MNEM_SUFFIX
-              && (stackop_size != LONG_MNEM_SUFFIX
-                  || i.tm.base_opcode != 0xcf)
               && !i.tm.opcode_modifier.ignoresize
               && !i.tm.opcode_modifier.floatmf
               && !i.tm.opcode_modifier.vex

diff --git a/gas/testsuite/gas/i386/jump16.d b/gas/testsuite/gas/i386/jump16.d
index 7a1dc7661ee332cde5c8773cc9bb933bcedd7b87..c883eba0e85088ef6574f53c7dc25afd9f8297b9 100644 (file)
--- a/gas/testsuite/gas/i386/jump16.d
+++ b/gas/testsuite/gas/i386/jump16.d
@@ -1,5 +1,6 @@
 #name: i386 jump16
 #objdump: -drw -mi8086
+#warning_output: jump16.e
 
 .*:     file format .*i386.*
 
@@ -69,4 +70,8 @@ Disassembly of section .text:
 [      ]*[a-f0-9]+:    ea 00 00 90 90          ljmp   \$0x9090,\$0x0   f2: (R_386_)?16 xxx
 [      ]*[a-f0-9]+:    cf                      iret   
 [      ]*[a-f0-9]+:    cf                      iret   
+[      ]*[a-f0-9]+:    66 cf                   iretl  
+[      ]*[a-f0-9]+:    cf                      iret   
+[      ]*[a-f0-9]+:    cf                      iret   
+[      ]*[a-f0-9]+:    66 cf                   iretl  
 #pass

diff --git a/gas/testsuite/gas/i386/jump16.e b/gas/testsuite/gas/i386/jump16.e
new file mode 100644 (file)
index 0000000..2ad7ea0
--- /dev/null
+++ b/gas/testsuite/gas/i386/jump16.e
@@ -0,0 +1,3 @@
+.*: Assembler messages:
+.*:77: Warning: generating 16-bit `iret' for .code16gcc directive
+.*:88: Warning: generating 16-bit `iret' for .code16gcc directive

diff --git a/gas/testsuite/gas/i386/jump16.s b/gas/testsuite/gas/i386/jump16.s
index aff5665720179579984c3a33efa35ee3eb85f4f7..fb9e830c52b532fed1fe5ae46d70c8049bad63ac 100644 (file)
--- a/gas/testsuite/gas/i386/jump16.s
+++ b/gas/testsuite/gas/i386/jump16.s
@@ -72,8 +72,24 @@
        jmp     0x9090,xxx
        jmp     0x9090:xxx
 
+       .att_syntax
 .code16gcc
        iret
+       iretw
+       iretl
 
 .code16
        iret
+       iretw
+       iretl
+
+       .intel_syntax noprefix
+.code16gcc
+       iret
+       iretw
+       iretd
+
+.code16
+       iret
+       iretw
+       iretd