[PATCH dwarves v8 1/5] dwarf_loader: Detect aggregate ABI register usage and clang compiler

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

Aggregate ABI register usage applies for both clang and gcc.
Detect clang compiler for occasional clang specific cases.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
---
 dwarf_loader.c | 24 ++++++++++++++++++++++++
 dwarves.h      |  2 ++
 2 files changed, 26 insertions(+)

diff --git a/dwarf_loader.c b/dwarf_loader.c
index 8ce34cb..11a2377 100644
--- a/dwarf_loader.c
+++ b/dwarf_loader.c
@@ -1137,6 +1137,16 @@ 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));
@@ -3154,6 +3164,17 @@ static unsigned long long dwarf_tag__orig_id(const struct tag *tag,
 	return cu->extra_dbg_info ? dtag->id : 0;
 }
 
+static bool attr_producer_clang(Dwarf_Die *die)
+{
+	const char *producer;
+
+	producer = attr_string(die, DW_AT_producer, NULL);
+	if (!producer)
+		return false;
+
+	return !!strstr(producer, "clang");
+}
+
 struct debug_fmt_ops dwarf__ops;
 
 static int die__process(Dwarf_Die *die, struct cu *cu, struct conf_load *conf)
@@ -3191,6 +3212,7 @@ static int die__process(Dwarf_Die *die, struct cu *cu, struct conf_load *conf)
 	}
 
 	cu->language = attr_numeric(die, DW_AT_language);
+	cu->producer_clang = attr_producer_clang(die);
 
 	if (conf->early_cu_filter)
 		cu = conf->early_cu_filter(cu);
@@ -3409,6 +3431,7 @@ 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;
 }
@@ -3950,6 +3973,7 @@ static int cus__merge_and_process_cu(struct cus *cus, struct conf_load *conf,
 			cu->priv = dcu;
 			cu->dfops = &dwarf__ops;
 			cu->language = attr_numeric(cu_die, DW_AT_language);
+			cu->producer_clang = attr_producer_clang(cu_die);
 			cus__add(cus, cu);
 		}
 
diff --git a/dwarves.h b/dwarves.h
index 75c311a..c0d7f5c 100644
--- a/dwarves.h
+++ b/dwarves.h
@@ -306,6 +306,8 @@ struct cu {
 	uint8_t		 has_addr_info:1;
 	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;
-- 
2.53.0-Meta