Sometimes compiler generates code to use the stack pointer register
without frame pointer.  As we know RSP is the stack register on x86,
let's treat it as same as fbreg.  But the offset would be opposite
direction so update the debug message accordingly.

Reported-by: Blake Jones <blakejones@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/arch/x86/annotate/instructions.c | 22 +++++++++++++++------
 tools/perf/util/annotate-data.c             | 15 +++++++++-----
 2 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/tools/perf/arch/x86/annotate/instructions.c b/tools/perf/arch/x86/annotate/instructions.c
index ae94b1f0b9cce1d3..c6d403eae7441168 100644
--- a/tools/perf/arch/x86/annotate/instructions.c
+++ b/tools/perf/arch/x86/annotate/instructions.c
@@ -410,7 +410,7 @@ static void update_insn_state_x86(struct type_state *state,
 
 retry:
 		/* Check stack variables with offset */
-		if (sreg == fbreg) {
+		if (sreg == fbreg || sreg == state->stack_reg) {
 			struct type_state_stack *stack;
 			int offset = src->offset - fboff;
 
@@ -433,8 +433,13 @@ static void update_insn_state_x86(struct type_state *state,
 				return;
 			}
 
-			pr_debug_dtp("mov [%x] -%#x(stack) -> reg%d",
-				     insn_offset, -offset, dst->reg1);
+			if (sreg == fbreg) {
+				pr_debug_dtp("mov [%x] -%#x(stack) -> reg%d",
+					     insn_offset, -offset, dst->reg1);
+			} else {
+				pr_debug_dtp("mov [%x] %#x(reg%d) -> reg%d",
+					     insn_offset, offset, sreg, dst->reg1);
+			}
 			pr_debug_type_name(&tsr->type, tsr->kind);
 		}
 		/* And then dereference the pointer if it has one */
@@ -561,7 +566,7 @@ static void update_insn_state_x86(struct type_state *state,
 			return;
 
 		/* Check stack variables with offset */
-		if (dst->reg1 == fbreg) {
+		if (dst->reg1 == fbreg || dst->reg1 == state->stack_reg) {
 			struct type_state_stack *stack;
 			int offset = dst->offset - fboff;
 
@@ -584,8 +589,13 @@ static void update_insn_state_x86(struct type_state *state,
 						    &tsr->type);
 			}
 
-			pr_debug_dtp("mov [%x] reg%d -> -%#x(stack)",
-				     insn_offset, src->reg1, -offset);
+			if (dst->reg1 == fbreg) {
+				pr_debug_dtp("mov [%x] reg%d -> -%#x(stack)",
+					     insn_offset, src->reg1, -offset);
+			} else {
+				pr_debug_dtp("mov [%x] reg%d -> %#x(reg%d)",
+					     insn_offset, src->reg1, offset, dst->reg1);
+			}
 			pr_debug_type_name(&tsr->type, tsr->kind);
 		}
 		/*
diff --git a/tools/perf/util/annotate-data.c b/tools/perf/util/annotate-data.c
index 976abedca09ef547..eaf96fa80c830d05 100644
--- a/tools/perf/util/annotate-data.c
+++ b/tools/perf/util/annotate-data.c
@@ -830,7 +830,7 @@ static void update_var_state(struct type_state *state, struct data_loc_info *dlo
 		if (!dwarf_offdie(dloc->di->dbg, var->die_off, &mem_die))
 			continue;
 
-		if (var->reg == DWARF_REG_FB || var->reg == fbreg) {
+		if (var->reg == DWARF_REG_FB || var->reg == fbreg || var->reg == state->stack_reg) {
 			int offset = var->offset;
 			struct type_state_stack *stack;
 
@@ -845,8 +845,13 @@ static void update_var_state(struct type_state *state, struct data_loc_info *dlo
 			findnew_stack_state(state, offset, TSR_KIND_TYPE,
 					    &mem_die);
 
-			pr_debug_dtp("var [%"PRIx64"] -%#x(stack)",
-				     insn_offset, -offset);
+			if (var->reg == state->stack_reg) {
+				pr_debug_dtp("var [%"PRIx64"] %#x(reg%d)",
+					     insn_offset, offset, state->stack_reg);
+			} else {
+				pr_debug_dtp("var [%"PRIx64"] -%#x(stack)",
+					     insn_offset, -offset);
+			}
 			pr_debug_type_name(&mem_die, TSR_KIND_TYPE);
 		} else if (has_reg_type(state, var->reg) && var->offset == 0) {
 			struct type_state_reg *reg;
@@ -1127,10 +1132,10 @@ static enum type_match_result check_matching_type(struct type_state *state,
 	}
 
 check_non_register:
-	if (reg == dloc->fbreg) {
+	if (reg == dloc->fbreg || reg == state->stack_reg) {
 		struct type_state_stack *stack;
 
-		pr_debug_dtp("fbreg");
+		pr_debug_dtp("%s", reg == dloc->fbreg ? "fbreg" : "stack");
 
 		stack = find_stack_state(state, dloc->type_offset);
 		if (stack == NULL) {
-- 
2.48.1.262.g85cc9f2d1e-goog

On Sun, 26 Jan 2025 13:02:42 -0800, Namhyung Kim wrote:
> Sometimes compiler generates code to use the stack pointer register
> without frame pointer.  As we know RSP is the stack register on x86,
> let's treat it as same as fbreg.  But the offset would be opposite
> direction so update the debug message accordingly.
> 
> 
Applied to perf-tools-next, thanks!

Best regards,
Namhyung