[binutils-gdb] PR30308, infinite recursion in i386_intel_simplify

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=2fbbadc2c336cad228be998a118e3bab3be30757

commit 2fbbadc2c336cad228be998a118e3bab3be30757
Author: Alan Modra <amodra@gmail.com>
Date:   Thu Feb 15 11:12:01 2024 +1030

    PR30308, infinite recursion in i386_intel_simplify
    
    This patch exposes the symbol "resolving" flag for use in
    i386_intel_simplify, not only preventing infinite recursion on the
    testcase in the PR but also more complicated cases like:
    
     .intel_syntax
     b = a
     a = b
     mov eax, [a]
    
            PR 30308
            * symbols.c (symbol_mark_resolving, symbol_clear_resolving),
            (symbol_resolving_p): New functions.
            * symbols.h: Declare them.
            * config/tc-i386-intel.c (i386_intel_simplify): Delete forward
            declaration.  Formatting.
            (i386_intel_simplify_symbol): Use resolving flag to prevent
            infinite recursion.

Diff:
---
 gas/config/tc-i386-intel.c | 22 +++++++++++++---------
 gas/symbols.c              | 24 +++++++++++++++++++++++-
 gas/symbols.h              |  3 +++
 3 files changed, 39 insertions(+), 10 deletions(-)

diff --git a/gas/config/tc-i386-intel.c b/gas/config/tc-i386-intel.c
index c95af419cf7..3011606d574 100644
--- a/gas/config/tc-i386-intel.c
+++ b/gas/config/tc-i386-intel.c
@@ -369,21 +369,25 @@ i386_intel_simplify_register (expressionS *e)
   return 2;
 }
 
-static int i386_intel_simplify (expressionS *);
-
-static INLINE int i386_intel_simplify_symbol(symbolS *sym)
+static int
+i386_intel_simplify_symbol (symbolS *sym)
 {
-  int ret = i386_intel_simplify (symbol_get_value_expression (sym));
+  if (symbol_resolving_p (sym))
+    return 1;
 
+  symbol_mark_resolving (sym);
+  int ret = i386_intel_simplify (symbol_get_value_expression (sym));
   if (ret == 2)
-  {
-    S_SET_SEGMENT(sym, absolute_section);
-    ret = 1;
-  }
+    {
+      S_SET_SEGMENT (sym, absolute_section);
+      ret = 1;
+    }
+  symbol_clear_resolving (sym);
   return ret;
 }
 
-static int i386_intel_simplify (expressionS *e)
+static int
+i386_intel_simplify (expressionS *e)
 {
   const reg_entry *the_reg = (this_operand >= 0
 			      ? i.op[this_operand].regs : NULL);
diff --git a/gas/symbols.c b/gas/symbols.c
index 41f273c85ff..4df83bab0e9 100644
--- a/gas/symbols.c
+++ b/gas/symbols.c
@@ -2936,7 +2936,7 @@ symbol_removed_p (symbolS *s)
   return s->flags.removed;
 }
 
-/* Mark a symbol has having been resolved.  */
+/* Mark a symbol as having been resolved.  */
 
 void
 symbol_mark_resolved (symbolS *s)
@@ -2952,6 +2952,28 @@ symbol_resolved_p (symbolS *s)
   return s->flags.resolved;
 }
 
+/* Mark a symbol as being resolved.  */
+
+void
+symbol_mark_resolving (symbolS *s)
+{
+  s->flags.resolving = 1;
+}
+
+void
+symbol_clear_resolving (symbolS *s)
+{
+  s->flags.resolving = 0;
+}
+
+/* Return whether a symbol is being resolved.  */
+
+int
+symbol_resolving_p (symbolS *s)
+{
+  return s->flags.resolving;
+}
+
 /* Return whether a symbol is a section symbol.  */
 
 int
diff --git a/gas/symbols.h b/gas/symbols.h
index 3232f1b2a33..c61fabcbe0a 100644
--- a/gas/symbols.h
+++ b/gas/symbols.h
@@ -206,6 +206,9 @@ extern void symbol_mark_removed (symbolS *);
 extern int symbol_removed_p (symbolS *);
 extern void symbol_mark_resolved (symbolS *);
 extern int symbol_resolved_p (symbolS *);
+extern void symbol_mark_resolving (symbolS *);
+extern void symbol_clear_resolving (symbolS *);
+extern int symbol_resolving_p (symbolS *);
 extern int symbol_section_p (symbolS *);
 extern int symbol_equated_p (symbolS *);
 extern int symbol_equated_reloc_p (symbolS *);