x86: permit parenthesized expressions again as addressing scale factor

The description of e68c3d59acd0 ("x86: better respect quotes in
parse_operands()") wrongly states:

"In i386_att_operand(), which needs adjustment to remain in sync, besides
 respecting double quotes now, also change the logic such that we don't
 count parentheses anymore: Finding any opening or closing parenthesis or
 any double quote means we're done, because the subsequent parsing code
 wouldn't accept (extra) instances of these anyway."

I didn't pay attention to the possibility of the scale factor being
specified as an expression, which may contain parentheses. Thanks to
Martin for pointing this out. Restore prior behavior or matching
parentheses (backwards), while giving the variable a more suitable name.
Note that this simple and immediate fix is not ging to be enough: This
expression could itself involve quoted symbols. However, to address this
backwards parsing needs to be done away with altogether here (such that
parentheses which are part of such a quoted symbol name can also
properly be accounted for), which is going to be a more intrusive
change.

5 files changed, 26 insertions, 2 deletions

diff --git a/gas/ChangeLog b/gas/ChangeLog
index ecd0794..d766fd1 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,11 @@
+2021-06-15  Jan Beulich  <jbeulich@suse.com>
+
+	* config/tc-i386.c (i386_att_operand): Re-introduce (now
+	properly named) parens_not_balanced.
+	* testsuite/gas/i386/sib.s: Add more cases.
+	* testsuite/gas/i386/sib.d, testsuite/gas/i386/sib-intel.d:
+	Adjust expectations.
+
 2021-06-14  Jan Beulich  <jbeulich@suse.com>
 
 	* read.c (emit_expr_with_reloc): Fold three as_warn().
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index b3f9f31..8585380 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -11566,15 +11566,19 @@ i386_att_operand (char *operand_string)
       if (*base_string == ')')
 	{
 	  char *temp_string;
+	  unsigned int parens_not_balanced = 1;
 
 	  /* We've already checked that the number of left & right ()'s are
 	     equal, so this loop will not be infinite.  */
 	  do
 	    {
 	      base_string--;
+	      if (*base_string == ')')
+		parens_not_balanced++;
+	      if (*base_string == '(')
+		parens_not_balanced--;
 	    }
-	  while (*base_string != '(' && *base_string != ')'
-		 && *base_string != '"');
+	  while (parens_not_balanced && *base_string != '"');
 
 	  temp_string = base_string;
 
diff --git a/gas/testsuite/gas/i386/sib-intel.d b/gas/testsuite/gas/i386/sib-intel.d
index 27709eb..ccd2ea9 100644
--- a/gas/testsuite/gas/i386/sib-intel.d
+++ b/gas/testsuite/gas/i386/sib-intel.d
@@ -30,6 +30,10 @@ Disassembly of section .text:
 [ 	]*[a-f0-9]+:	8b 04 64             	mov    eax,DWORD PTR \[esp\+eiz\*2\]
 [ 	]*[a-f0-9]+:	8b 04 a4             	mov    eax,DWORD PTR \[esp\+eiz\*4\]
 [ 	]*[a-f0-9]+:	8b 04 e4             	mov    eax,DWORD PTR \[esp\+eiz\*8\]
+[ 	]*[a-f0-9]+:	8b 04 00             	mov    eax,DWORD PTR \[eax\+eax\*1\]
+[ 	]*[a-f0-9]+:	8b 04 40             	mov    eax,DWORD PTR \[eax\+eax\*2\]
+[ 	]*[a-f0-9]+:	8b 04 80             	mov    eax,DWORD PTR \[eax\+eax\*4\]
+[ 	]*[a-f0-9]+:	8b 04 c0             	mov    eax,DWORD PTR \[eax\+eax\*8\]
 [ 	]*[a-f0-9]+:	8b 04 25 e2 ff ff ff 	mov    eax,DWORD PTR \[eiz\*1-0x1e\]
 [ 	]*[a-f0-9]+:	8b 04 65 e2 ff ff ff 	mov    eax,DWORD PTR \[eiz\*2-0x1e\]
 [ 	]*[a-f0-9]+:	8b 04 a5 e2 ff ff ff 	mov    eax,DWORD PTR \[eiz\*4-0x1e\]
diff --git a/gas/testsuite/gas/i386/sib.d b/gas/testsuite/gas/i386/sib.d
index 0ece418..151935c 100644
--- a/gas/testsuite/gas/i386/sib.d
+++ b/gas/testsuite/gas/i386/sib.d
@@ -29,6 +29,10 @@ Disassembly of section .text:
 [ 	]*[a-f0-9]+:	8b 04 64             	mov    \(%esp,%eiz,2\),%eax
 [ 	]*[a-f0-9]+:	8b 04 a4             	mov    \(%esp,%eiz,4\),%eax
 [ 	]*[a-f0-9]+:	8b 04 e4             	mov    \(%esp,%eiz,8\),%eax
+[ 	]*[a-f0-9]+:	8b 04 00             	mov    \(%eax,%eax,1\),%eax
+[ 	]*[a-f0-9]+:	8b 04 40             	mov    \(%eax,%eax,2\),%eax
+[ 	]*[a-f0-9]+:	8b 04 80             	mov    \(%eax,%eax,4\),%eax
+[ 	]*[a-f0-9]+:	8b 04 c0             	mov    \(%eax,%eax,8\),%eax
 [ 	]*[a-f0-9]+:	8b 04 25 e2 ff ff ff 	mov    -0x1e\(,%eiz,1\),%eax
 [ 	]*[a-f0-9]+:	8b 04 65 e2 ff ff ff 	mov    -0x1e\(,%eiz,2\),%eax
 [ 	]*[a-f0-9]+:	8b 04 a5 e2 ff ff ff 	mov    -0x1e\(,%eiz,4\),%eax
diff --git a/gas/testsuite/gas/i386/sib.s b/gas/testsuite/gas/i386/sib.s
index 430da42..c0e007f 100644
--- a/gas/testsuite/gas/i386/sib.s
+++ b/gas/testsuite/gas/i386/sib.s
@@ -26,6 +26,10 @@ foo:
 	mov	(%esp,%eiz,2),%eax
 	mov	(%esp,%eiz,4),%eax
 	mov	(%esp,%eiz,8),%eax
+	mov	(%eax, %eax, (1 << 0)), %eax
+	mov	(%eax, %eax, (1 << 1)), %eax
+	mov	(%eax, %eax, (1 << 2)), %eax
+	mov	(%eax, %eax, (1 << 3)), %eax
 	.intel_syntax noprefix
         mov    eax,DWORD PTR [eiz*1-30]
         mov    eax,DWORD PTR [eiz*2-30]