[RFC/PATCH 1/2] sparse, llvm: Make function declaration accessible to backend

From: Linus Torvalds <torvalds <at> linux-foundation.org>

On Tue, Aug 30, 2011 at 10:43 AM, Jeff Garzik <jeff <at> garzik.org> wrote:
> * if someone knows how to access a function declaration, I can solve the
> varargs problem

Hmm. Right now we do not have access to the function declaration at
linearize time. We've checked that the arguments match, and we've cast
the arguments to the right types (evaluate.c), so the thinking was
that you just use the arguments as-is.

But if llvm needs the declaration of a function, we'd need to squirrel it away.

Cc: Benjamin Herrenschmidt <benh <at> kernel.crashing.org>
Cc: Christopher Li <sparse <at> chrisli.org>
Cc: Jeff Garzik <jgarzik <at> redhat.com>
Cc: Linus Torvalds <torvalds <at> linux-foundation.org>
[ penberg <at> kernel.org: Fix validation/context.c breakage. ]
Signed-off-by: Pekka Enberg <penberg <at> kernel.org>
---
 linearize.c |    8 ++++++++
 linearize.h |    1 +
 2 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/linearize.c b/linearize.c
index 1899978..7d57474 100644
--- a/linearize.c
+++ b/linearize.c
@@ -1195,6 +1195,7 @@ static pseudo_t linearize_call_expression(struct entrypoint *ep, struct expressi
 	struct instruction *insn = alloc_typed_instruction(OP_CALL, expr->ctype);
 	pseudo_t retval, call;
 	struct ctype *ctype = NULL;
+	struct symbol *fntype;
 	struct context *context;

 	if (!expr->ctype) {
@@ -1212,6 +1213,13 @@ static pseudo_t linearize_call_expression(struct entrypoint *ep, struct expressi
 	if (fn->ctype)
 		ctype = &fn->ctype->ctype;

+	fntype = fn->ctype;
+	if (fntype) {
+		if (fntype->type == SYM_NODE)
+			fntype = fntype->ctype.base_type;
+	}
+	insn->fntype = fntype;
+
 	if (fn->type == EXPR_PREOP) {
 		if (fn->unop->type == EXPR_SYMBOL) {
 			struct symbol *sym = fn->unop->symbol;
diff --git a/linearize.h b/linearize.h
index 424ba97..61fbd83 100644
--- a/linearize.h
+++ b/linearize.h
@@ -116,6 +116,7 @@ struct instruction {
 		struct /* call */ {
 			pseudo_t func;
 			struct pseudo_list *arguments;
+			struct symbol *fntype;
 		};
 		struct /* context */ {
 			int increment;
--

-- 
1.7.6.4

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