PR11343: backward compatibility option/conditional

* main.cxx: Add "--compatible=VERSION" option.
* session.h (compatible): Store it.
* parse.cxx (eval_pp_conditional): Look at it as %( systemtap_v CMP VALUE ... %)
* stap.1.in: Document it.
* testsuite/parseko/preprocess17.stp, parseok/twenty.stp: Test it.

1 files changed, 13 insertions, 6 deletions

diff --git a/parse.cxx b/parse.cxx
index 6cdf76d9..72bfdd96 100644
--- a/parse.cxx
+++ b/parse.cxx
@@ -183,6 +183,7 @@ bool eval_comparison (const OPERAND& lhs, const token* op, const OPERAND& rhs)
 // The basic form is %( CONDITION %? THEN-TOKENS %: ELSE-TOKENS %)
 // where CONDITION is: kernel_v[r] COMPARISON-OP "version-string"
 //                 or: arch COMPARISON-OP "arch-string"
+//                 or: systemtap_v COMPARISON-OP "version-string"
 //                 or: CONFIG_foo COMPARISON-OP "config-string"
 //                 or: CONFIG_foo COMPARISON-OP number
 //                 or: CONFIG_foo COMPARISON-OP CONFIG_bar
@@ -202,17 +203,21 @@ bool eval_pp_conditional (systemtap_session& s,
                           const token* l, const token* op, const token* r)
 {
   if (l->type == tok_identifier && (l->content == "kernel_v" ||
-                                    l->content == "kernel_vr"))
+                                    l->content == "kernel_vr" || 
+                                    l->content == "systemtap_v"))
     {
+      if (! (r->type == tok_string))
+        throw parse_error ("expected string literal", r);
+
       string target_kernel_vr = s.kernel_release;
       string target_kernel_v = s.kernel_base_release;
+      string target;
 
-      if (! (r->type == tok_string))
-        throw parse_error ("expected string literal", r);
+      if (l->content == "kernel_v") target = target_kernel_v;
+      else if (l->content == "kernel_vr") target = target_kernel_vr;
+      else if (l->content == "systemtap_v") target = s.compatible;
+      else assert (0);
 
-      string target = (l->content == "kernel_vr" ?
-                       target_kernel_vr.c_str() :
-                       target_kernel_v.c_str());
       string query = r->content;
       bool rhs_wildcard = (strpbrk (query.c_str(), "*?[") != 0);
 
@@ -2471,6 +2476,8 @@ expression* parser::parse_symbol ()
       if (name == "@cast" || (name.size()>0 && name[0] == '$'))
         return parse_target_symbol (t);
 
+      // NB: PR11343: @defined() is not incompatible with earlier versions
+      // of stap, so no need to check session.compatible for 1.2
       if (name == "@defined")
         return parse_defined_op (t);