[PATCH dwarves v4 08/11] dwarf_loader: Check whether two-reg parameter actually use two regs or not

[Yonghong Song <yonghong.song@linux.dev>]

For a parameter whose type occuplies two registers, for x86_64 and aarch64,
the parameter will actually use two registers. S390 is different
as it allocates on stack and pass a pointer to the function.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
 dwarf_loader.c | 11 +++++++++++
 dwarves.h      |  1 +
 2 files changed, 12 insertions(+)

diff --git a/dwarf_loader.c b/dwarf_loader.c
index ed2f384..d538e97 100644
--- a/dwarf_loader.c
+++ b/dwarf_loader.c
@@ -1100,6 +1100,16 @@ static void arch__set_register_params(const GElf_Ehdr *ehdr, struct cu *cu)
 	}
 }
 
+static bool arch__agg_use_two_regs(const GElf_Ehdr *ehdr)
+{
+	switch (ehdr->e_machine) {
+	case EM_S390:
+		return false;
+	default:
+		return true;
+	}
+}
+
 static struct template_type_param *template_type_param__new(Dwarf_Die *die, struct cu *cu, struct conf_load *conf)
 {
 	struct template_type_param *ttparm = tag__alloc(cu, sizeof(*ttparm));
@@ -3557,6 +3567,7 @@ static int cu__set_common(struct cu *cu, struct conf_load *conf,
 
 	cu->little_endian = ehdr.e_ident[EI_DATA] == ELFDATA2LSB;
 	cu->nr_register_params = arch__nr_register_params(&ehdr);
+	cu->agg_use_two_regs = arch__agg_use_two_regs(&ehdr);
 	arch__set_register_params(&ehdr, cu);
 	return 0;
 }
diff --git a/dwarves.h b/dwarves.h
index 4cabab0..164bd3b 100644
--- a/dwarves.h
+++ b/dwarves.h
@@ -303,6 +303,7 @@ struct cu {
 	uint8_t		 uses_global_strings:1;
 	uint8_t		 little_endian:1;
 	uint8_t		 producer_clang:1;
+	uint8_t		 agg_use_two_regs:1;	/* An aggregate like {long a; long b;} */
 	uint8_t		 nr_register_params;
 	int		 register_params[ARCH_MAX_REGISTER_PARAMS];
 	int		 functions_saved;
-- 
2.52.0