gas: consistently drop trailing whitespace when scrubbing

From especially the checks for the two separator forms it appears to
follow that the construct being touched is about trailing whitespace. In
such a case, considering that for many targets ordinary and line comment
chars overlap, take into account that line comment chars override
ordinary ones in lex[] (logic elsewhere in do_scrub_chars() actually
depends on that ordering, and also accounts for this overriding).

Plus of course IS_NEWLINE() would better also be consulted. Note also
that the DOUBLESLASH_LINE_COMMENTS change should generally have no
effect just yet; it's a prereq for a later change but better fits here.

Leave respective comments as well, and update documentation to correct
which comment form is actually replaced by a single blank (i.e. neither
the ones starting with what {,tc_}comment_chars[] has nor the ones
starting with what line_comment_chars[] has).

8 files changed, 34 insertions, 15 deletions

diff --git a/gas/app.c b/gas/app.c
index 3ac5e2a..e580e0f 100644
--- a/gas/app.c
+++ b/gas/app.c
@@ -87,6 +87,7 @@ static char last_char;
 #define IS_PARALLEL_SEPARATOR(c)	(lex[c] == LEX_IS_PARALLEL_SEPARATOR)
 #define IS_COMMENT(c)			(lex[c] == LEX_IS_COMMENT_START)
 #define IS_LINE_COMMENT(c)		(lex[c] == LEX_IS_LINE_COMMENT_START)
+#define IS_TWOCHAR_COMMENT_1ST(c)	(lex[c] == LEX_IS_TWOCHAR_COMMENT_1ST)
 #define	IS_NEWLINE(c)			(lex[c] == LEX_IS_NEWLINE)
 
 static char lex[256] = {
@@ -197,6 +198,9 @@ do_scrub_begin (int m68k_mri ATTRIBUTE_UNUSED)
   for (p = tc_comment_chars; *p; p++)
     lex[(unsigned char) *p] = LEX_IS_COMMENT_START;
 
+  /* While counter intuitive to have more special purpose line comment chars
+     override more general purpose ordinary ones, logic in do_scrub_chars()
+     depends on this ordering.   */
   for (p = line_comment_chars; *p; p++)
     lex[(unsigned char) *p] = LEX_IS_LINE_COMMENT_START;
 
@@ -962,7 +966,12 @@ do_scrub_chars (size_t (*get) (char *, size_t), char *tostart, size_t tolen,
 		}
 	    }
 #endif
+
+	  /* Prune trailing whitespace.  */
 	  if (IS_COMMENT (ch)
+	      || (IS_LINE_COMMENT (ch)
+	          && (state < 1 || strchr (tc_comment_chars, ch)))
+	      || IS_NEWLINE (ch)
 	      || IS_LINE_SEPARATOR (ch)
 	      || IS_PARALLEL_SEPARATOR (ch))
 	    {
@@ -975,6 +984,16 @@ do_scrub_chars (size_t (*get) (char *, size_t), char *tostart, size_t tolen,
 		}
 	      goto recycle;
 	    }
+#ifdef DOUBLESLASH_LINE_COMMENTS
+	  if (IS_TWOCHAR_COMMENT_1ST (ch))
+	    {
+	      ch2 = GET ();
+	      if (ch2 != EOF)
+	        UNGET (ch2);
+	      if (ch2 == '/')
+		goto recycle;
+	    }
+#endif
 
 	  /* If we're in state 2 or 11, we've seen a non-white
 	     character followed by whitespace.  If the next character
diff --git a/gas/doc/as.texi b/gas/doc/as.texi
index b2a3f24..3501744 100644
--- a/gas/doc/as.texi
+++ b/gas/doc/as.texi
@@ -2990,11 +2990,11 @@ as exactly one space.
 @section Comments
 
 @cindex comments
-There are two ways of rendering comments to @command{@value{AS}}.  In both
-cases the comment is equivalent to one space.
+There are two ways of rendering comments to @command{@value{AS}}.
 
 Anything from @samp{/*} through the next @samp{*/} is a comment.
-This means you may not nest these comments.
+This means you may not nest these comments.  Such a comment is equivalent to
+one space, plus bumping the line counter accordingly.
 
 @smallexample
 /*
diff --git a/gas/testsuite/gas/mips/mips16-32@mips16-insn-e.l b/gas/testsuite/gas/mips/mips16-32@mips16-insn-e.l
index d0a305d..45b31d6 100644
--- a/gas/testsuite/gas/mips/mips16-32@mips16-insn-e.l
+++ b/gas/testsuite/gas/mips/mips16-32@mips16-insn-e.l
@@ -25,7 +25,7 @@
 .*:50: Warning: extended operand requested but not required
 .*:51: Error: opcode not supported on this processor: mips1 \(mips1\) `restore\.e 128'
 .*:52: Error: opcode not supported on this processor: mips1 \(mips1\) `save\.e 128'
-.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e '
+.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e'
 .*:54: Error: unrecognized extended version of MIPS16 opcode `move\.e \$0,\$16'
 .*:55: Error: unrecognized extended version of MIPS16 opcode `move\.e \$16,\$0'
 .*:57: Warning: extended operand requested but not required
@@ -71,7 +71,7 @@
 .*:123: Error: unrecognized extended version of MIPS16 opcode `srav\.e \$16,\$16'
 .*:124: Error: operand 2 must be an immediate expression `sra\.e \$16,\$16'
 .*:125: Error: opcode not supported on this processor: mips1 \(mips1\) `dsrl\.e \$16,8'
-.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e '
+.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e'
 .*:127: Error: unrecognized extended version of MIPS16 opcode `entry\.e \$31'
 .*:128: Error: unrecognized extended version of MIPS16 opcode `exit\.e \$f0'
 .*:129: Error: unrecognized extended version of MIPS16 opcode `exit\.e'
diff --git a/gas/testsuite/gas/mips/mips16-64@mips16-insn-e.l b/gas/testsuite/gas/mips/mips16-64@mips16-insn-e.l
index 62f3979..97f3c49 100644
--- a/gas/testsuite/gas/mips/mips16-64@mips16-insn-e.l
+++ b/gas/testsuite/gas/mips/mips16-64@mips16-insn-e.l
@@ -25,7 +25,7 @@
 .*:50: Warning: extended operand requested but not required
 .*:51: Error: opcode not supported on this processor: mips3 \(mips3\) `restore\.e 128'
 .*:52: Error: opcode not supported on this processor: mips3 \(mips3\) `save\.e 128'
-.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e '
+.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e'
 .*:54: Error: unrecognized extended version of MIPS16 opcode `move\.e \$0,\$16'
 .*:55: Error: unrecognized extended version of MIPS16 opcode `move\.e \$16,\$0'
 .*:57: Warning: extended operand requested but not required
@@ -71,7 +71,7 @@
 .*:123: Error: unrecognized extended version of MIPS16 opcode `srav\.e \$16,\$16'
 .*:124: Error: operand 2 must be an immediate expression `sra\.e \$16,\$16'
 .*:125: Warning: extended operand requested but not required
-.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e '
+.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e'
 .*:127: Error: unrecognized extended version of MIPS16 opcode `entry\.e \$31'
 .*:128: Error: unrecognized extended version of MIPS16 opcode `exit\.e \$f0'
 .*:129: Error: unrecognized extended version of MIPS16 opcode `exit\.e'
diff --git a/gas/testsuite/gas/mips/mips16-insn-e.l b/gas/testsuite/gas/mips/mips16-insn-e.l
index 0527389..32aa003 100644
--- a/gas/testsuite/gas/mips/mips16-insn-e.l
+++ b/gas/testsuite/gas/mips/mips16-insn-e.l
@@ -23,7 +23,7 @@
 .*:48: Warning: extended operand requested but not required
 .*:49: Warning: extended operand requested but not required
 .*:50: Warning: extended operand requested but not required
-.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e '
+.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e'
 .*:54: Error: unrecognized extended version of MIPS16 opcode `move\.e \$0,\$16'
 .*:55: Error: unrecognized extended version of MIPS16 opcode `move\.e \$16,\$0'
 .*:57: Warning: extended operand requested but not required
@@ -69,7 +69,7 @@
 .*:123: Error: unrecognized extended version of MIPS16 opcode `srav\.e \$16,\$16'
 .*:124: Error: operand 2 must be an immediate expression `sra\.e \$16,\$16'
 .*:125: Warning: extended operand requested but not required
-.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e '
+.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e'
 .*:127: Error: unrecognized extended version of MIPS16 opcode `entry\.e \$31'
 .*:128: Error: unrecognized extended version of MIPS16 opcode `exit\.e \$f0'
 .*:129: Error: unrecognized extended version of MIPS16 opcode `exit\.e'
diff --git a/gas/testsuite/gas/mips/mips16e-32@mips16-insn-e.l b/gas/testsuite/gas/mips/mips16e-32@mips16-insn-e.l
index 4ec4797..a66cc35 100644
--- a/gas/testsuite/gas/mips/mips16e-32@mips16-insn-e.l
+++ b/gas/testsuite/gas/mips/mips16e-32@mips16-insn-e.l
@@ -23,7 +23,7 @@
 .*:48: Warning: extended operand requested but not required
 .*:49: Warning: extended operand requested but not required
 .*:50: Warning: extended operand requested but not required
-.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e '
+.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e'
 .*:54: Error: unrecognized extended version of MIPS16 opcode `move\.e \$0,\$16'
 .*:55: Error: unrecognized extended version of MIPS16 opcode `move\.e \$16,\$0'
 .*:57: Warning: extended operand requested but not required
@@ -69,7 +69,7 @@
 .*:123: Error: unrecognized extended version of MIPS16 opcode `srav\.e \$16,\$16'
 .*:124: Error: operand 2 must be an immediate expression `sra\.e \$16,\$16'
 .*:125: Error: opcode not supported on this processor: mips32 \(mips32\) `dsrl\.e \$16,8'
-.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e '
+.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e'
 .*:127: Error: unrecognized extended version of MIPS16 opcode `entry\.e \$31'
 .*:128: Error: unrecognized extended version of MIPS16 opcode `exit\.e \$f0'
 .*:129: Error: unrecognized extended version of MIPS16 opcode `exit\.e'
diff --git a/gas/testsuite/gas/mips/mips16e2-32@mips16-insn-e.l b/gas/testsuite/gas/mips/mips16e2-32@mips16-insn-e.l
index 474110c..095e0b0 100644
--- a/gas/testsuite/gas/mips/mips16e2-32@mips16-insn-e.l
+++ b/gas/testsuite/gas/mips/mips16e2-32@mips16-insn-e.l
@@ -23,7 +23,7 @@
 .*:48: Warning: extended operand requested but not required
 .*:49: Warning: extended operand requested but not required
 .*:50: Warning: extended operand requested but not required
-.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e '
+.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e'
 .*:54: Error: unrecognized extended version of MIPS16 opcode `move\.e \$0,\$16'
 .*:55: Error: unrecognized extended version of MIPS16 opcode `move\.e \$16,\$0'
 .*:57: Warning: extended operand requested but not required
@@ -69,7 +69,7 @@
 .*:123: Error: unrecognized extended version of MIPS16 opcode `srav\.e \$16,\$16'
 .*:124: Error: operand 2 must be an immediate expression `sra\.e \$16,\$16'
 .*:125: Error: opcode not supported on this processor: mips32r2 \(mips32r2\) `dsrl\.e \$16,8'
-.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e '
+.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e'
 .*:127: Error: unrecognized extended version of MIPS16 opcode `entry\.e \$31'
 .*:128: Error: unrecognized extended version of MIPS16 opcode `exit\.e \$f0'
 .*:129: Error: unrecognized extended version of MIPS16 opcode `exit\.e'
diff --git a/gas/testsuite/gas/mips/mips16e2-interaptiv-mr2@mips16-insn-e.l b/gas/testsuite/gas/mips/mips16e2-interaptiv-mr2@mips16-insn-e.l
index 3fd6457..a0c55df 100644
--- a/gas/testsuite/gas/mips/mips16e2-interaptiv-mr2@mips16-insn-e.l
+++ b/gas/testsuite/gas/mips/mips16e2-interaptiv-mr2@mips16-insn-e.l
@@ -23,7 +23,7 @@
 .*:48: Warning: extended operand requested but not required
 .*:49: Warning: extended operand requested but not required
 .*:50: Warning: extended operand requested but not required
-.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e '
+.*:53: Error: unrecognized extended version of MIPS16 opcode `nop\.e'
 .*:54: Error: unrecognized extended version of MIPS16 opcode `move\.e \$0,\$16'
 .*:55: Error: unrecognized extended version of MIPS16 opcode `move\.e \$16,\$0'
 .*:57: Warning: extended operand requested but not required
@@ -69,7 +69,7 @@
 .*:123: Error: unrecognized extended version of MIPS16 opcode `srav\.e \$16,\$16'
 .*:124: Error: operand 2 must be an immediate expression `sra\.e \$16,\$16'
 .*:125: Error: opcode not supported on this processor: interaptiv-mr2 \(mips32r3\) `dsrl\.e \$16,8'
-.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e '
+.*:126: Error: unrecognized extended version of MIPS16 opcode `entry\.e'
 .*:127: Error: unrecognized extended version of MIPS16 opcode `entry\.e \$31'
 .*:128: Error: unrecognized extended version of MIPS16 opcode `exit\.e \$f0'
 .*:129: Error: unrecognized extended version of MIPS16 opcode `exit\.e'