[v1,13/18] add insert_phi_node()

Commit Message

Luc Van Oostenryck March 20, 2018, 12:52 a.m. UTC

This helper is used later during the SSA construction and is,
as its name suggest, used to insert phi-nodes in the
instruction stream.

More exactly, the phi-node will be put at the begining of the
specified BB, just after the others phi-nodes but before
any other instructions, as required for their semantics
(although, it's less important for sparse since each operand
correspond first to a phi-source, so no phi-node directly
depending on themselves in sparse).

Signed-off-by: Luc Van Oostenryck <[e-mail]>
---
 linearize.c | 36 ++++++++++++++++++++++++++++++++++++
 linearize.h |  3 +++
 2 files changed, 39 insertions(+)

Patch

diff --git a/linearize.c b/linearize.c
index 4cd2c75eb..d35842b1f 100644
--- a/linearize.c
+++ b/linearize.c
@@ -871,6 +871,42 @@  pseudo_t alloc_phi(struct basic_block *source, pseudo_t pseudo, struct symbol *t
 	return insn->target;
 }
 
+struct instruction *alloc_phi_node(struct basic_block *bb, struct symbol *type, struct ident *ident)
+{
+	struct instruction *phi_node = alloc_typed_instruction(OP_PHI, type);
+	pseudo_t phi;
+
+	phi = alloc_pseudo(phi_node);
+	phi->ident = ident;
+	phi->def = phi_node;
+	phi_node->target = phi;
+	phi_node->bb = bb;
+	return phi_node;
+}
+
+void add_phi_node(struct basic_block *bb, struct instruction *phi_node)
+{
+	struct instruction *insn;
+
+	FOR_EACH_PTR(bb->insns, insn) {
+		enum opcode op = insn->opcode;
+		if (op == OP_PHI)
+			continue;
+		INSERT_CURRENT(phi_node, insn);
+		return;
+	} END_FOR_EACH_PTR(insn);
+
+	// FIXME
+	add_instruction(&bb->insns, phi_node);
+}
+
+struct instruction *insert_phi_node(struct basic_block *bb, struct symbol *var)
+{
+	struct instruction *phi_node = alloc_phi_node(bb, var, var->ident);
+	add_phi_node(bb, phi_node);
+	return phi_node;
+}
+
 /*
  * We carry the "access_data" structure around for any accesses,
  * which simplifies things a lot. It contains all the access
diff --git a/linearize.h b/linearize.h
index 0285e28d3..0aaf11da5 100644
--- a/linearize.h
+++ b/linearize.h
@@ -377,6 +377,9 @@  extern void insert_select(struct basic_block *bb, struct instruction *br, struct
 extern void insert_branch(struct basic_block *bb, struct instruction *br, struct basic_block *target);
 
 struct instruction *alloc_phisrc(pseudo_t pseudo, struct symbol *type);
+struct instruction *alloc_phi_node(struct basic_block *bb, struct symbol *type, struct ident *ident);
+struct instruction *insert_phi_node(struct basic_block *bb, struct symbol *var);
+void add_phi_node(struct basic_block *bb, struct instruction *phi_node);
 
 pseudo_t alloc_phi(struct basic_block *source, pseudo_t pseudo, struct symbol *type);
 pseudo_t alloc_pseudo(struct instruction *def);