From e6b616c076d4500266d0b2ca185f07a616d552fe Mon Sep 17 00:00:00 2001
From: Andrzej Turko <andrzej.turko@gmail.com>
Date: Mon, 7 Aug 2023 11:59:00 +0200
Subject: genmatch: Reduce variability of generated code

So far genmatch has been using an unordered map to store information about
functions to be generated. Since corresponding locations from match.pd were
used as keys in the map, even small changes to match.pd which caused
line number changes would change the order in which the functions are
generated. This would reshuffle the functions between the generated .cc files.
This way even a minimal modification to match.pd forces recompilation of all
object files originating from match.pd on rebuild.

This commit makes sure that functions are generated in the order of their
processing (in contrast to the random order based on hashes of their
locations in match.pd). This is done by replacing the unordered map with an
ordered one. This way small changes to match.pd does not cause function
renaming and reshuffling among generated source files.
Together with the subsequent change to logging fprintf calls, this
removes unnecessary changes to the files generated by genmatch allowing
for reuse of already built object files during rebuild. The aim is to
make editing of match.pd and subsequent testing easier.

Signed-off-by: Andrzej Turko <andrzej.turko@gmail.com>

gcc/ChangeLog:

	* genmatch.cc: Make sinfo map ordered.
	* Makefile.in: Require the ordered map header for genmatch.o.
---
 gcc/Makefile.in | 4 ++--
 gcc/genmatch.cc | 3 ++-
 2 files changed, 4 insertions(+), 3 deletions(-)

(limited to 'gcc')

diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index e99628c..2429128 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -3004,8 +3004,8 @@ build/genhooks.o : genhooks.cc $(TARGET_DEF) $(C_TARGET_DEF)		\
   $(COMMON_TARGET_DEF) $(D_TARGET_DEF) $(BCONFIG_H) $(SYSTEM_H) errors.h
 build/genmddump.o : genmddump.cc $(RTL_BASE_H) $(BCONFIG_H) $(SYSTEM_H)	\
   $(CORETYPES_H) $(GTM_H) errors.h $(READ_MD_H) $(GENSUPPORT_H)
-build/genmatch.o : genmatch.cc $(BCONFIG_H) $(SYSTEM_H) \
-  $(CORETYPES_H) errors.h $(HASH_TABLE_H) hash-map.h $(GGC_H) is-a.h \
+build/genmatch.o : genmatch.cc $(BCONFIG_H) $(SYSTEM_H) $(CORETYPES_H) \
+  errors.h $(HASH_TABLE_H) hash-map.h $(GGC_H) is-a.h ordered-hash-map.h \
   tree.def builtins.def internal-fn.def case-cfn-macros.h $(CPPLIB_H)
 build/gencfn-macros.o : gencfn-macros.cc $(BCONFIG_H) $(SYSTEM_H)	\
   $(CORETYPES_H) errors.h $(HASH_TABLE_H) hash-set.h builtins.def	\
diff --git a/gcc/genmatch.cc b/gcc/genmatch.cc
index 2302f2a..1deca50 100644
--- a/gcc/genmatch.cc
+++ b/gcc/genmatch.cc
@@ -29,6 +29,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "hash-table.h"
 #include "hash-set.h"
 #include "is-a.h"
+#include "ordered-hash-map.h"
 
 
 /* Stubs for GGC referenced through instantiations triggered by hash-map.  */
@@ -1684,7 +1685,7 @@ struct sinfo_hashmap_traits : simple_hashmap_traits<pointer_hash<dt_simplify>,
   template <typename T> static inline void remove (T &) {}
 };
 
-typedef hash_map<void * /* unused */, sinfo *, sinfo_hashmap_traits>
+typedef ordered_hash_map<void * /* unused */, sinfo *, sinfo_hashmap_traits>
   sinfo_map_t;
 
 /* Current simplifier ID we are processing during insertion into the
-- 
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