[PATCH] convert TREE_CHAIN to DECL_CHAIN where appropriate

[Nathan Froyd <froydnj at codesourcery dot com>]

One of the problems with slimming down the common bits of the tree data
structure is the multi-purposing of fields in that common part.  While
abstraction macros have been used for many other multi-purposed fields,
they have (generally) not been used for the fields in tree_common.

The attached patch addresses (part of) that by introducing DECL_CHAIN to
make it obvious when DECLs are being chained together as opposed to
generic TREE_LISTs or similar.  Such a change has already been done for
BLOCK_CHAIN.  Making this change paves the way for an eventual pushing
down of tree_common.chain into only structures that use it.  (There are
a number of changes remaining before that pushdown can happen:
cp/cp-tree.h needs extensive housekeeping, there's some GC issues to
address, etc.)

This patch does not add specialized functions like decl_nreverse to be
used on chains of decls.  That would be an appropriate followup patch.

I don't claim to have caught all places where this substitution needs to
occur.  My strategy for producing this patch was, roughly:

- make TREE_CHAIN error when given a DECL;

- replace erroring occurrences with DECL_CHAIN.

(I'm not submitting the erroring bits at this time, though they would be
a useful followup patch once, say, the C++ FE is cleaned up.)

So it's certainly possible that there are some codepaths that still use
TREE_CHAIN when they could be using DECL_CHAIN.  This patch is a good
start, though.

The tree this patch is against is a couple days old.  If the patch is
approved, I'd like to rebase it against trunk with the above error
checking enabled, re-bootstrap, fix errors, and commit.  If the
reviewer(s) don't like that idea, I'm happy to submit followup patches
for smaller-scale DECL_CHAINification.

Bootstrapped and tested on x86_64-unknown-linux-gnu with all languages
and checking enabled, no regressions.  Tested with cross to arm-eabi,
powerpc-eabispe, and mips-elf with --enable-languages=c, no regressions.
(Testing with powerpc and mips still ongoing, but no surprises
expected.)  OK to commit?

-Nathan

gcc/
	* tree.h (DECL_CHAIN): Define.
	* alias.c: Carefully replace TREE_CHAIN with DECL_CHAIN.
	* c-decl.c: Likewise.
	* c-parser.c: Likewise.
	* c-typeck.c: Likewise.
	* cfgexpand.c: Likewise.
	* cgraph.c: Likewise.
	* cgraphunit.c: Likewise.
	* combine.c: Likewise.
	* config/alpha/alpha.c: Likewise.
	* config/arm/arm.c: Likewise.
	* config/frv/frv.c: Likewise.
	* config/i386/i386.c: Likewise.
	* config/i386/winnt-cxx.c: Likewise.
	* config/ia64/ia64.c: Likewise.
	* config/iq2000/iq2000.c: Likewise.
	* config/mep/mep.c: Likewise.
	* config/mips/mips.c: Likewise.
	* config/pa/som.h: Likewise.
	* config/rs6000/rs6000.c: Likewise.
	* config/s390/s390.c: Likewise.
	* config/sh/sh.c: Likewise.
	* config/sh/symbian-cxx.c: Likewise.
	* config/sparc/sparc.c: Likewise.
	* config/spu/spu.c: Likewise.
	* config/stormy16/stormy16.c: Likewise.
	* config/vxworks.c: Likewise.
	* config/xtensa/xtensa.c: Likewise.
	* coverage.c: Likewise.
	* dbxout.c: Likewise.
	* dwarf2out.c: Likewise.
	* emit-rtl.c: Likewise.
	* expr.c: Likewise.
	* function.c: Likewise.
	* gimple-low.c: Likewise.
	* gimple-pretty-print.c: Likewise.
	* gimplify.c: Likewise.
	* integrate.c: Likewise.
	* ipa-inline.c: Likewise.
	* ipa-prop.c: Likewise.
	* ipa-split.c: Likewise.
	* ipa-struct-reorg.c: Likewise.
	* ipa-type-escape.c: Likewise.
	* langhooks.c: Likewise.
	* lto-cgraph.c: Likewise.
	* omp-low.c: Likewise.
	* stor-layout.c: Likewise.
	* tree-cfg.c: Likewise.
	* tree-complex.c: Likewise.
	* tree-dfa.c: Likewise.
	* tree-dump.c: Likewise.
	* tree-inline.c: Likewise.
	* tree-mudflap.c: Likewise.
	* tree-nested.c: Likewise.
	* tree-object-size.c: Likewise.
	* tree-pretty-print.c: Likewise.
	* tree-sra.c: Likewise.
	* tree-ssa-live.c: Likewise.
	* tree-ssa-loop-niter.c: Likewise.
	* tree-ssa-math-opts.c: Likewise.
	* tree-ssa-reassoc.c: Likewise.
	* tree-ssa-sccvn.c: Likewise.
	* tree-ssa-structalias.c: Likewise.
	* tree-tailcall.c: Likewise.
	* tree-vrp.c: Likewise.
	* tree.c: Likewise.
	* var-tracking.c: Likewise.
	* varasm.c: Likewise.

gcc/ada/
	* gcc-interface/decl.c: Carefully replace TREE_CHAIN with
	DECL_CHAIN.
	* gcc-interface/trans.c: Likewise.
	* gcc-interface/utils.c: Likewise.
	* gcc-interface/utils2.c: Likewise.

gcc/c-family/
	* c-common.c: Carefully replace TREE_CHAIN with DECL_CHAIN.
	* c-format.c: Likewise.

gcc/cp/
	* cp-tree.h: Carefully replace TREE_CHAIN with DECL_CHAIN.
	* call.c: Likewise.
	* class.c: Likewise.
	* cp-gimplify.c: Likewise.
	* decl.c: Likewise.
	* decl2.c: Likewise.
	* init.c: Likewise.
	* mangle.c: Likewise.
	* name-lookup.c: Likewise.
	* optimize.c: Likewise.
	* parser.c: Likewise.
	* pt.c: Likewise.
	* rtti.c: Likewise.
	* search.c: Likewise.
	* semantics.c: Likewise.
	* typeck.c: Likewise.
	* typeck2.c: Likewise.

gcc/fortran/
	* f95-lang.c: Carefully replace TREE_CHAIN with DECL_CHAIN.
	* trans-common.c: Likewise.
	* trans-decl.c: Likewise.
	* trans-types.c: Likewise.
	* trans.c: Likewise.

gcc/java/
	* java-tree.h: Carefully replace TREE_CHAIN with DECL_CHAIN.
	* boehm.c: Likewise.
	* class.c: Likewise.
	* decl.c: Likewise.
	* expr.c: Likewise.
	* jcf-parse.c: Likewise.
	* typeck.c: Likewise.
	* verify-glue.c: Likewise.

gcc/objc/
	* objc-act.c: Carefully replace TREE_CHAIN with DECL_CHAIN.

gcc/testsuite/
	* g++.dg/plugin/attribute_plugin.c: Carefully replace TREE_CHAIN
	with DECL_CHAIN.

Attachment: decl-chain.patch.gz
Description: Binary data