[gcc r12-2971] Turn global 'ggc_force_collect' variable into 'force_collect' parameter to 'ggc_collect'

[gcc r12-2971] Turn global 'ggc_force_collect' variable into 'force_collect' parameter to 'ggc_collect'

[Thomas Schwinge]

https://gcc.gnu.org/g:0edf2e81bb02cba43b649b3f6e7258b68a779ac0

commit r12-2971-g0edf2e81bb02cba43b649b3f6e7258b68a779ac0
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Tue Aug 17 10:47:02 2021 +0200

    Turn global 'ggc_force_collect' variable into 'force_collect' parameter to 'ggc_collect'
    
    This simplifies the interface and gets us rid of a global variable.
    No change in behavior.
    
    Clean-up for 2004-09-02 CVS commit (Subversion r86974,
    Git commit 0772402279c0161fe41784911b52c77e12803c42)
    "Better memory statistics, take 2".
    
            gcc/
            * ggc.h (ggc_collect): Add 'force_collect' parameter.
            * ggc-page.c (ggc_collect): Use that one instead of global
            'ggc_force_collect'.  Adjust all users.
            * doc/gty.texi (Invoking the garbage collector): Update.
            * ggc-internal.h (ggc_force_collect): Remove.
            * ggc-common.c (ggc_force_collect): Likewise.
            * selftest.h (forcibly_ggc_collect): Remove.
            * ggc-tests.c (selftest::forcibly_ggc_collect): Likewise.
            * read-rtl-function.c (test_loading_labels): Adjust.
            * selftest-run-tests.c (run_tests): Likewise.

Diff:
---
 gcc/doc/gty.texi         |  5 ++++-
 gcc/ggc-common.c         |  8 +-------
 gcc/ggc-internal.h       |  3 ---
 gcc/ggc-page.c           |  4 ++--
 gcc/ggc-tests.c          | 29 +++++++++--------------------
 gcc/ggc.h                |  6 ++++--
 gcc/read-rtl-function.c  |  2 +-
 gcc/selftest-run-tests.c |  2 +-
 gcc/selftest.h           |  5 -----
 9 files changed, 22 insertions(+), 42 deletions(-)

diff --git a/gcc/doc/gty.texi b/gcc/doc/gty.texi
index cf070c1f7f7..b667d1d19ba 100644
--- a/gcc/doc/gty.texi
+++ b/gcc/doc/gty.texi
@@ -654,7 +654,10 @@ The GCC garbage collector GGC is only invoked explicitly. In contrast
 with many other garbage collectors, it is not implicitly invoked by
 allocation routines when a lot of memory has been consumed. So the
 only way to have GGC reclaim storage is to call the @code{ggc_collect}
-function explicitly.  This call is an expensive operation, as it may
+function explicitly.
+When the @var{force_collect} parameter is set or otherwise an internal
+heuristic decides whether to actually collect, this call is
+potentially an expensive operation, as it may
 have to scan the entire heap.  Beware that local variables (on the GCC
 call stack) are not followed by such an invocation (as many other
 garbage collectors do): you should reference all your data from static
diff --git a/gcc/ggc-common.c b/gcc/ggc-common.c
index 357bda13f97..f38e4d5020d 100644
--- a/gcc/ggc-common.c
+++ b/gcc/ggc-common.c
@@ -31,9 +31,6 @@ along with GCC; see the file COPYING3.  If not see
 #include "plugin.h"
 #include "options.h"
 
-/* When set, ggc_collect will do collection.  */
-bool ggc_force_collect;
-
 /* When true, protect the contents of the identifier hash table.  */
 bool ggc_protect_identifiers = true;
 
@@ -965,12 +962,9 @@ dump_ggc_loc_statistics ()
   if (! GATHER_STATISTICS)
     return;
 
-  ggc_force_collect = true;
-  ggc_collect ();
+  ggc_collect (true);
 
   ggc_mem_desc.dump (GGC_ORIGIN);
-
-  ggc_force_collect = false;
 }
 
 /* Record ALLOCATED and OVERHEAD bytes to descriptor NAME:LINE (FUNCTION).  */
diff --git a/gcc/ggc-internal.h b/gcc/ggc-internal.h
index 39850cd6230..4dcfb4c008c 100644
--- a/gcc/ggc-internal.h
+++ b/gcc/ggc-internal.h
@@ -88,9 +88,6 @@ extern void ggc_pch_read (FILE *, void *);
 
 /* Allocation and collection.  */
 
-/* When set, ggc_collect will do collection.  */
-extern bool ggc_force_collect;
-
 extern void ggc_record_overhead (size_t, size_t, void * FINAL_MEM_STAT_DECL);
 
 extern void ggc_free_overhead (void *);
diff --git a/gcc/ggc-page.c b/gcc/ggc-page.c
index 1b09f0da94f..a6fbecaa1d8 100644
--- a/gcc/ggc-page.c
+++ b/gcc/ggc-page.c
@@ -2184,7 +2184,7 @@ validate_free_objects (void)
 /* Top level mark-and-sweep routine.  */
 
 void
-ggc_collect (void)
+ggc_collect (bool force_collect)
 {
   /* Avoid frequent unnecessary work by skipping collection if the
      total allocations haven't expanded much since the last
@@ -2196,7 +2196,7 @@ ggc_collect (void)
   memory_block_pool::trim ();
 
   float min_expand = allocated_last_gc * param_ggc_min_expand / 100;
-  if (G.allocated < allocated_last_gc + min_expand && !ggc_force_collect)
+  if (G.allocated < allocated_last_gc + min_expand && !force_collect)
     return;
 
   timevar_push (TV_GC);
diff --git a/gcc/ggc-tests.c b/gcc/ggc-tests.c
index 4ee95506625..2891c20ceac 100644
--- a/gcc/ggc-tests.c
+++ b/gcc/ggc-tests.c
@@ -22,21 +22,10 @@ along with GCC; see the file COPYING3.  If not see
 #include "coretypes.h"
 #include "tree-core.h"
 #include "tree.h"
-#include "ggc-internal.h" /* (for ggc_force_collect).  */
 #include "selftest.h"
 
 #if CHECKING_P
 
-/* A helper function for writing ggc tests.  */
-
-void
-selftest::forcibly_ggc_collect ()
-{
-  ggc_force_collect = true;
-  ggc_collect ();
-  ggc_force_collect = false;
-}
-
 /* The various GTY markers must be outside of a namespace to be seen by
    gengtype, so we don't put this file within the selftest namespace.  */
 
@@ -58,7 +47,7 @@ test_basic_struct ()
   root_test_struct = ggc_cleared_alloc <test_struct> ();
   root_test_struct->other = ggc_cleared_alloc <test_struct> ();
 
-  selftest::forcibly_ggc_collect ();
+  ggc_collect (true);
 
   ASSERT_TRUE (ggc_marked_p (root_test_struct));
   ASSERT_TRUE (ggc_marked_p (root_test_struct->other));
@@ -88,7 +77,7 @@ test_length ()
   for (int i = 0; i < count; i++)
     root_test_of_length->elem[i] = ggc_cleared_alloc <test_of_length> ();
 
-  selftest::forcibly_ggc_collect ();
+  ggc_collect (true);
 
   ASSERT_TRUE (ggc_marked_p (root_test_of_length));
   for (int i = 0; i < count; i++)
@@ -162,7 +151,7 @@ test_union ()
   test_struct *referenced_by_other = ggc_cleared_alloc <test_struct> ();
   other->m_ptr = referenced_by_other;
 
-  selftest::forcibly_ggc_collect ();
+  ggc_collect (true);
 
   ASSERT_TRUE (ggc_marked_p (root_test_of_union_1));
   ASSERT_TRUE (ggc_marked_p (ts));
@@ -203,7 +192,7 @@ test_finalization ()
 
   test_struct_with_dtor::dtor_call_count = 0;
 
-  selftest::forcibly_ggc_collect ();
+  ggc_collect (true);
 
   /* Verify that the destructor was run for each instance.  */
   ASSERT_EQ (count, test_struct_with_dtor::dtor_call_count);
@@ -221,7 +210,7 @@ test_deletable_global ()
   test_of_deletable = ggc_cleared_alloc <test_struct> ();
   ASSERT_TRUE (test_of_deletable != NULL);
 
-  selftest::forcibly_ggc_collect ();
+  ggc_collect (true);
 
   ASSERT_EQ (NULL, test_of_deletable);
 }
@@ -294,7 +283,7 @@ test_inheritance ()
   test_some_subclass_as_base_ptr = new some_subclass ();
   test_some_other_subclass_as_base_ptr = new some_other_subclass ();
 
-  selftest::forcibly_ggc_collect ();
+  ggc_collect (true);
 
   /* Verify that the roots and everything referenced by them got marked
      (both for fields in the base class and those in subclasses).  */
@@ -373,7 +362,7 @@ test_chain_next ()
       tail_node = new_node;
     }
 
-  selftest::forcibly_ggc_collect ();
+  ggc_collect (true);
 
   /* If we got here, we survived.  */
 
@@ -440,7 +429,7 @@ test_user_struct ()
 
   num_calls_to_user_gt_ggc_mx = 0;
 
-  selftest::forcibly_ggc_collect ();
+  ggc_collect (true);
 
   ASSERT_TRUE (ggc_marked_p (root_user_struct_ptr));
   ASSERT_TRUE (ggc_marked_p (referenced));
@@ -458,7 +447,7 @@ test_tree_marking ()
 {
   dummy_unittesting_tree = build_int_cst (integer_type_node, 1066);
 
-  selftest::forcibly_ggc_collect ();
+  ggc_collect (true);
 
   ASSERT_TRUE (ggc_marked_p (dummy_unittesting_tree));
 }
diff --git a/gcc/ggc.h b/gcc/ggc.h
index 92884717f5c..0f640b255e8 100644
--- a/gcc/ggc.h
+++ b/gcc/ggc.h
@@ -262,8 +262,10 @@ extern const char *ggc_alloc_string (const char *contents, int length
 #define ggc_strdup(S) ggc_alloc_string ((S), -1 MEM_STAT_INFO)
 
 /* Invoke the collector.  Garbage collection occurs only when this
-   function is called, not during allocations.  */
-extern void ggc_collect	(void);
+   function is called, not during allocations.
+   Unless FORCE_COLLECT, an internal heuristic decides whether to actually
+   collect.  */
+extern void ggc_collect (bool force_collect = false);
 
 /* Return unused memory pages to the system.  */
 extern void ggc_trim (void);
diff --git a/gcc/read-rtl-function.c b/gcc/read-rtl-function.c
index ca580d3f71e..0badfb98f9d 100644
--- a/gcc/read-rtl-function.c
+++ b/gcc/read-rtl-function.c
@@ -1861,7 +1861,7 @@ test_loading_labels ()
 
   /* Ensure that label names read from a dump are GC-managed
      and are found through the insn.  */
-  forcibly_ggc_collect ();
+  ggc_collect (true);
   ASSERT_TRUE (ggc_marked_p (insn_200));
   ASSERT_TRUE (ggc_marked_p (LABEL_NAME (insn_200)));
 }
diff --git a/gcc/selftest-run-tests.c b/gcc/selftest-run-tests.c
index 1b5583e476a..10881fce230 100644
--- a/gcc/selftest-run-tests.c
+++ b/gcc/selftest-run-tests.c
@@ -128,7 +128,7 @@ selftest::run_tests ()
      issues.  For example, if any GC-managed items have buggy (or missing)
      finalizers, this last collection will ensure that things that were
      failed to be finalized can be detected by valgrind.  */
-  forcibly_ggc_collect ();
+  ggc_collect (true);
 
   /* Finished running tests; the test_runner dtor will print a summary.  */
 }
diff --git a/gcc/selftest.h b/gcc/selftest.h
index 80459d63a39..58d8d383cee 100644
--- a/gcc/selftest.h
+++ b/gcc/selftest.h
@@ -190,11 +190,6 @@ for_each_line_table_case (void (*testcase) (const line_table_case &));
 
 extern char *read_file (const location &loc, const char *path);
 
-/* A helper function for writing tests that interact with the
-   garbage collector.  */
-
-extern void forcibly_ggc_collect ();
-
 /* Convert a path relative to SRCDIR/gcc/testsuite/selftests
    to a real path (either absolute, or relative to pwd).
    The result should be freed by the caller.  */