In some cases (e.g. coverage testing) it is useful to emit code for static
functions even if they are never used, which currently is not possible at -O1
and above. The following patch introduces a flag for this, which basically
triggers the same code that keeps those functions alive at -O0. Thanks to Marc
Glisse for replying at gcc-help and for suggesting where to look.
Bootstrapped and regtested on x86_64-unknown-linux-gnu
OK for trunk ?
Joost
gcc/ChangeLog:
2015-10-17 Joost VandeVondele <vond...@gnu.gcc.org>
PR middle-end/68002
* common.opt (fkeep-static-functions): New option.
* doc/invoke.texi: Document it.
* cgraphunit.c (cgraph_node::finalize_function): Use it.
gcc/testsuite/ChangeLog:
2015-10-17 Joost VandeVondele <vond...@gnu.gcc.org>
PR middle-end/68002
* gcc.dg/PR68002.c: New test.
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 228932)
+++ gcc/doc/invoke.texi (working copy)
@@ -410,8 +410,8 @@ Objective-C and Objective-C++ Dialects}.
-fira-loop-pressure -fno-ira-share-save-slots @gol
-fno-ira-share-spill-slots -fira-verbose=@var{n} @gol
-fisolate-erroneous-paths-dereference -fisolate-erroneous-paths-attribute @gol
--fivopts -fkeep-inline-functions -fkeep-static-consts @gol
--flive-range-shrinkage @gol
+-fivopts -fkeep-inline-functions -fkeep-static-functions @gol
+-fkeep-static-consts -flive-range-shrinkage @gol
-floop-block -floop-interchange -floop-strip-mine @gol
-floop-unroll-and-jam -floop-nest-optimize @gol
-floop-parallelize-all -flra-remat -flto -flto-compression-level @gol
@@ -8013,6 +8013,11 @@ of its callers. This switch does not af
@code{extern inline} extension in GNU C90@. In C++, emit any and all
inline functions into the object file.
+@item -fkeep-static-functions
+@optindex fkeep-static-functions
+Emit @code{static} functions into the object file, even if the function
+is never used.
+
@item -fkeep-static-consts
@opindex fkeep-static-consts
Emit variables declared @code{static const} when optimization isn't turned
Index: gcc/cgraphunit.c
===================================================================
--- gcc/cgraphunit.c (revision 228932)
+++ gcc/cgraphunit.c (working copy)
@@ -451,7 +451,7 @@ cgraph_node::finalize_function (tree dec
declared inline and nested functions. These were optimized out
in the original implementation and it is unclear whether we want
to change the behavior here. */
- if ((!opt_for_fn (decl, optimize)
+ if (((!opt_for_fn (decl, optimize) || flag_keep_static_functions)
&& !node->cpp_implicit_alias
&& !DECL_DISREGARD_INLINE_LIMITS (decl)
&& !DECL_DECLARED_INLINE_P (decl)
Index: gcc/testsuite/gcc.dg/PR68002.c
===================================================================
--- gcc/testsuite/gcc.dg/PR68002.c (revision 0)
+++ gcc/testsuite/gcc.dg/PR68002.c (revision 0)
@@ -0,0 +1,7 @@
+/* Ensure static functions can be kept. */
+/* { dg-do compile } */
+/* { dg-options "-O1 -fkeep-static-functions" } */
+
+static void bar () { }
+
+/* { dg-final { scan-assembler "bar" } } */
Index: gcc/common.opt
===================================================================
--- gcc/common.opt (revision 228932)
+++ gcc/common.opt (working copy)
@@ -1589,6 +1589,10 @@ fkeep-inline-functions
Common Report Var(flag_keep_inline_functions)
Generate code for functions even if they are fully inlined
+fkeep-static-functions
+Common Report Var(flag_keep_static_functions)
+Generate code for static functions even if they are never called
+
fkeep-static-consts
Common Report Var(flag_keep_static_consts) Init(1)
Emit static const variables even if they are not used
