Subject: [PATCH V3 10/14] tools/perf: Update instruction tracking for powerpc

From: Athira Rajeev <[email-masked]>
Date: Sat, 1 Jun 2024 11:39:37 +0530

Add instruction tracking function "update_insn_state_powerpc" for
powerpc. Example sequence in powerpc:

ld      r10,264(r3)
mr      r31,r3
<<after some sequence>
ld      r9,312(r31)

Consider ithe sample is pointing to: "ld r9,312(r31)".
Here the memory reference is hit at "312(r31)" where 312 is the offset
and r31 is the source register. Previous instruction sequence shows that
register state of r3 is moved to r31. So to identify the data type for r31
access, the previous instruction ("mr") needs to be tracked and the
state type entry has to be updated. Current instruction tracking support
in perf tools infrastructure is specific to x86. Patch adds this support
for powerpc as well.

Signed-off-by: Athira Rajeev <[email-masked]>
---
 .../perf/arch/powerpc/annotate/instructions.c | 65 +++++++++++++++++++
 tools/perf/util/annotate-data.c               |  9 ++-
 tools/perf/util/disasm.c                      |  1 +
 3 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/tools/perf/arch/powerpc/annotate/instructions.c b/tools/perf/arch/powerpc/annotate/instructions.c
index db72148eb857..3ecf5a986037 100644
--- a/tools/perf/arch/powerpc/annotate/instructions.c
+++ b/tools/perf/arch/powerpc/annotate/instructions.c
@@ -231,6 +231,71 @@ static struct ins_ops *check_ppc_insn(int raw_insn)
 	return NULL;
 }
 
+/*
+ * Instruction tracking function to track register state moves.
+ * Example sequence:
+ *    ld      r10,264(r3)
+ *    mr      r31,r3
+ *    <<after some sequence>
+ *    ld      r9,312(r31)
+ *
+ * Previous instruction sequence shows that register state of r3
+ * is moved to r31. update_insn_state_powerpc tracks these state
+ * changes
+ */
+#ifdef HAVE_DWARF_SUPPORT
+static void update_insn_state_powerpc(struct type_state *state,
+		struct data_loc_info *dloc, Dwarf_Die * cu_die __maybe_unused,
+		struct disasm_line *dl)
+{
+	struct annotated_insn_loc loc;
+	struct annotated_op_loc *src = &loc.ops[INSN_OP_SOURCE];
+	struct annotated_op_loc *dst = &loc.ops[INSN_OP_TARGET];
+	struct type_state_reg *tsr;
+	u32 insn_offset = dl->al.offset;
+
+	if (annotate_get_insn_location(dloc->arch, dl, &loc) < 0)
+		return;
+
+	/*
+	 * Value 444 for bits 21:30 is for "mr"
+	 * instruction. "mr" is extended OR. So set the
+	 * source and destination reg correctly
+	 */
+	if (PPC_21_30(dl->ops.raw_insn) == 444) {
+		int src_reg = src->reg1;
+
+		src->reg1 = dst->reg1;
+		dst->reg1 = src_reg;
+	}
+
+	if (!has_reg_type(state, dst->reg1))
+		return;
+
+	tsr = &state->regs[dst->reg1];
+
+	if (!has_reg_type(state, src->reg1) ||
+			!state->regs[src->reg1].ok) {
+		tsr->ok = false;
+		return;
+	}
+
+	tsr->type = state->regs[src->reg1].type;
+	tsr->kind = state->regs[src->reg1].kind;
+	tsr->ok = true;
+
+	pr_debug("mov [%x] reg%d -> reg%d",
+			insn_offset, src->reg1, dst->reg1);
+	pr_debug_type_name(&tsr->type, tsr->kind);
+}
+#else /* HAVE_DWARF_SUPPORT */
+static void update_insn_state_powerpc(struct type_state *state __maybe_unused, struct data_loc_info *dloc __maybe_unused,
+		Dwarf_Die * cu_die __maybe_unused, struct disasm_line *dl __maybe_unused)
+{
+	return;
+}
+#endif /* HAVE_DWARF_SUPPORT */
+
 static int powerpc__annotate_init(struct arch *arch, char *cpuid __maybe_unused)
 {
 	if (!arch->initialized) {
diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index 7a48c3d72b89..734acdd8c4b7 100644
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -1080,6 +1080,13 @@ static int find_data_type_insn(struct data_loc_info *dloc,
 	return ret;
 }
 
+static int arch_supports_insn_tracking(struct data_loc_info *dloc)
+{
+	if ((arch__is(dloc->arch, "x86")) || (arch__is(dloc->arch, "powerpc")))
+		return 1;
+	return 0;
+}
+
 /*
  * Construct a list of basic blocks for each scope with variables and try to find
  * the data type by updating a type state table through instructions.
@@ -1094,7 +1101,7 @@ static int find_data_type_block(struct data_loc_info *dloc,
 	int ret = -1;
 
 	/* TODO: other architecture support */
-	if (!arch__is(dloc->arch, "x86"))
+	if (!arch_supports_insn_tracking(dloc))
 		return -1;
 
 	prev_dst_ip = dst_ip = dloc->ip;
diff --git a/tools/perf/util/disasm.c b/tools/perf/util/disasm.c
index 57af4dc42a58..d8b357055302 100644
--- a/tools/perf/util/disasm.c
+++ b/tools/perf/util/disasm.c
@@ -155,6 +155,7 @@ static struct arch architectures[] = {
 	{
 		.name = "powerpc",
 		.init = powerpc__annotate_init,
+		.update_insn_state = update_insn_state_powerpc,
 	},
 	{
 		.name = "riscv64",
-- 
2.43.0