[binutils-gdb] gas: sanitize FB- and dollar-label uses

[binutils-gdb] gas: sanitize FB- and dollar-label uses

[Jan Beulich]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=226749d5a6ff0d5c607d6428d6c81e1e7e7a994b

commit 226749d5a6ff0d5c607d6428d6c81e1e7e7a994b
Author: Jan Beulich <jbeulich@suse.com>
Date:   Thu Mar 28 11:53:59 2024 +0100

    gas: sanitize FB- and dollar-label uses
    
    I don't view it as sensible to be more lax when it comes to references
    to (uses of) such labels compared to their definition: The latter has
    been limited to decimal numerics, while the former permitted any radix.
    Beyond that leading zeroes on such labels aren't helpful either. Imo
    labels and their use sites would better match literally, to avoid
    confusion.
    
    As it turns out, one z80 testcase actually had such an odd use of labels
    where definition and use don't match in spelling. That testcase is being
    adjusted accordingly.
    
    While there also adjust a comment on a local variable in
    integer_constant().

Diff:
---
 gas/NEWS                     |  4 ++++
 gas/expr.c                   | 23 +++++++++++++----------
 gas/read.c                   |  4 ++++
 gas/testsuite/gas/z80/sdcc.s | 20 ++++++++++----------
 4 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/gas/NEWS b/gas/NEWS
index 92b02de00cd..f48edd4b8c3 100644
--- a/gas/NEWS
+++ b/gas/NEWS
@@ -1,5 +1,9 @@
 -*- text -*-
 
+* References to FB and dollar labels, when supported, are no longer permitted
+  in a radix other than 10.  (Note that definitions of such labels were already
+  thus restricted, except that leading zeroes were permitted.)
+
 * Remove support for RISC-V privileged spec 1.9.1, but linker can still
   recognize it in case of linking old objects.
 
diff --git a/gas/expr.c b/gas/expr.c
index 3a01b88e310..79db30f873e 100644
--- a/gas/expr.c
+++ b/gas/expr.c
@@ -284,7 +284,7 @@ integer_constant (int radix, expressionS *expressionP)
   char *name;		/* Points to name of symbol.  */
   symbolS *symbolP;	/* Points to symbol.  */
 
-  int small;			/* True if fits in 32 bits.  */
+  bool small;		/* True if fits in 32 bits (64 bits with BFD64).  */
 
   /* May be bignum, or may fit in 32 bits.  */
   /* Most numbers fit into 32 bits, and we want this case to be fast.
@@ -549,10 +549,12 @@ integer_constant (int radix, expressionS *expressionP)
 #ifndef tc_allow_L_suffix
 #define tc_allow_L_suffix 1
 #endif
+  bool l_seen = !tc_allow_L_suffix;
   /* PR 20732: Look for, and ignore, a L or LL suffix to the number.  */
   if (tc_allow_L_suffix && (c == 'L' || c == 'l'))
     {
       c = * input_line_pointer++;
+      l_seen = true;
       if (c == 'L' || c == 'l')
 	c = *input_line_pointer++;
       if (!u_seen && (c == 'U' || c == 'u'))
@@ -561,13 +563,14 @@ integer_constant (int radix, expressionS *expressionP)
 
   if (small)
     {
-      /* Here with number, in correct radix. c is the next char.
-	 Note that unlike un*x, we allow "011f" "0x9f" to both mean
-	 the same as the (conventional) "9f".
-	 This is simply easier than checking for strict canonical
-	 form.  Syntax sux!  */
-
-      if (LOCAL_LABELS_FB && c == 'b')
+      /* Here with number, in correct radix. c is the next char.  */
+      bool maybe_label = suffix == NULL
+			 && (!tc_allow_U_suffix || !u_seen)
+			 && (!tc_allow_L_suffix || !l_seen)
+			 && (radix == 10 ||
+			     (radix == 8 && input_line_pointer == start + 1));
+
+      if (LOCAL_LABELS_FB && c == 'b' && maybe_label)
 	{
 	  /* Backward ref to local label.
 	     Because it is backward, expect it to be defined.  */
@@ -593,7 +596,7 @@ integer_constant (int radix, expressionS *expressionP)
 
 	  expressionP->X_add_number = 0;
 	}			/* case 'b' */
-      else if (LOCAL_LABELS_FB && c == 'f')
+      else if (LOCAL_LABELS_FB && c == 'f' && maybe_label)
 	{
 	  /* Forward reference.  Expect symbol to be undefined or
 	     unknown.  undefined: seen it before.  unknown: never seen
@@ -609,7 +612,7 @@ integer_constant (int radix, expressionS *expressionP)
 	  expressionP->X_add_symbol = symbolP;
 	  expressionP->X_add_number = 0;
 	}			/* case 'f' */
-      else if (LOCAL_LABELS_DOLLAR && c == '$')
+      else if (LOCAL_LABELS_DOLLAR && c == '$' && maybe_label)
 	{
 	  /* If the dollar label is *currently* defined, then this is just
 	     another reference to it.  If it is not *currently* defined,
diff --git a/gas/read.c b/gas/read.c
index 8c1e399b63f..61a3f172674 100644
--- a/gas/read.c
+++ b/gas/read.c
@@ -1269,6 +1269,10 @@ read_a_source_file (const char *name)
 	      while (ISDIGIT (*input_line_pointer))
 		{
 		  const long digit = *input_line_pointer - '0';
+
+		  /* Don't accept labels which look like octal numbers.  */
+		  if (temp == 0)
+		    break;
 		  if (temp > (INT_MAX - digit) / 10)
 		    {
 		      as_bad (_("local label too large near %s"), backup);
diff --git a/gas/testsuite/gas/z80/sdcc.s b/gas/testsuite/gas/z80/sdcc.s
index 5fe9288c220..98994276ced 100644
--- a/gas/testsuite/gas/z80/sdcc.s
+++ b/gas/testsuite/gas/z80/sdcc.s
@@ -13,7 +13,7 @@ valueadr = 0x1234
 _start::
 ;comment
 	ld      hl, #4+0
-00000$:
+0$:
 	adc	a, a
 	adc	a, b
 	adc	a, c
@@ -29,7 +29,7 @@ _start::
 	adc	a, (hl)
 	adc	a, 5 (ix)
 	adc	a, -2 (iy)
-00100$:
+100$:
 	add	a, a
 	add	a, b
 	add	a, c
@@ -45,7 +45,7 @@ _start::
 	add	a, (hl)
 	add	a, 5 (ix)
 	add	a, -2 (iy)
-00200$:
+200$:
 	and	a, a
 	and	a, b
 	and	a, c
@@ -61,7 +61,7 @@ _start::
 	and	a, (hl)
 	and	a, 5 (ix)
 	and	a, -2 (iy)
-00300$:
+300$:
 	cp	a, a
 	cp	a, b
 	cp	a, c
@@ -77,7 +77,7 @@ _start::
 	cp	a, (hl)
 	cp	a, 5 (ix)
 	cp	a, -2 (iy)
-00400$:
+400$:
 	or	a, a
 	or	a, b
 	or	a, c
@@ -93,7 +93,7 @@ _start::
 	or	a, (hl)
 	or	a, 5 (ix)
 	or	a, -2 (iy)
-00500$:
+500$:
 	sbc	a, a
 	sbc	a, b
 	sbc	a, c
@@ -109,7 +109,7 @@ _start::
 	sbc	a, (hl)
 	sbc	a, 5 (ix)
 	sbc	a, -2 (iy)
-00600$:
+600$:
 	sub	a, a
 	sub	a, b
 	sub	a, c
@@ -125,7 +125,7 @@ _start::
 	sub	a, (hl)
 	sub	a, 5 (ix)
 	sub	a, -2 (iy)
-00700$:
+700$:
 	xor	a, a
 	xor	a, b
 	xor	a, c
@@ -152,10 +152,10 @@ _start::
 _func:
 	ld	hl,0
 	ld	(hl),#<function
-00100$:
+100$:
 	inc	hl
 	ld	(hl),#>function
-00600$:
+600$:
 	jr	100$
 _finish::
 	ld	a, 2 (iy)