2006-04-25 Frank Ch. Eigler <fche@elastic.org>

	PR 2427.
	* staptree.cxx (varuse_collecting_visitor::visit_embeddedcode):
	Support /* pure */ declaration.  Stop using __tvar_ naming hack.
	(v_c_u::visit_print_format): Mark sprint and sprintf as
	side-effect-free.
	(deep_copy_visitor::visit_print_format): Propagate raw_components.
	* stap.1.in: Document declaration.
	* elaborate.cxx (semantic_pass_opt2): Verbose message tweak.
	(dead_stmtexpr_remover): Extend for more aggressive optimization.
	* tapsets.cxx (dwarf,mark_var_expanding_copy_visotor): Add
	/* pure */ declaration to rvalue expansions.
	* tapset/*.stp: Added /* pure */ declarations to many functions.
	* testsuite/parseok/unparsers.stp: Propagate guru mode flag.
	* testsuite/buildok/twentyfour.stp: New test.

1 files changed, 7 insertions, 4 deletions

diff --git a/stap.1.in b/stap.1.in
index c3ce0725..387fe640 100644
--- a/stap.1.in
+++ b/stap.1.in
@@ -646,10 +646,13 @@ with "$") are found and have their run-time locations decoded.
 .PP
 Next, all probes and functions are analyzed for optimization
 opportunities, in order to remove variables, expressions, and
-functions that have no useful value and no side-effect.  Since this
-process can hide latent code errors such as type mismatches or invalid
-$target variables, it sometimes may be useful to disable the
-optimizations with the
+functions that have no useful value and no side-effect.  Embedded-C
+functions are assumed to have side-effects unless they include the
+magic string
+.BR /*\ pure\ */ .
+Since this optimization can hide latent code errors such as type
+mismatches or invalid $target variables, it sometimes may be useful
+to disable the optimizations with the
 .BR \-u
 option. 
 .PP