diff --git a/elf/elf.h b/elf/elf.h
index 0d8acd55f7..3cfc8e6064 100644
--- a/elf/elf.h
+++ b/elf/elf.h
@@ -1136,9 +1136,9 @@ struct Elf64Sym {
   }
 
   ul32 st_name;
-  u8 st_type : 4;
-  u8 st_bind : 4;
-  u8 st_visibility : 2;
+  u8 st_type : 4 = 0;
+  u8 st_bind : 4 = 0;
+  u8 st_visibility : 2 = 0;
   ul16 st_shndx;
   ul64 st_value;
   ul64 st_size;
@@ -1162,9 +1162,9 @@ struct Elf32Sym {
   ul32 st_name;
   ul32 st_value;
   ul32 st_size;
-  u8 st_type : 4;
-  u8 st_bind : 4;
-  u8 st_visibility : 2;
+  u8 st_type : 4 = 0;
+  u8 st_bind : 4 = 0;
+  u8 st_visibility : 2 = 0;
   ul16 st_shndx;
 };
 
@@ -1195,7 +1195,7 @@ struct Elf32Shdr {
 };
 
 struct Elf64Ehdr {
-  u8 e_ident[16];
+  u8 e_ident[16] = {};
   ul16 e_type;
   ul16 e_machine;
   ul32 e_version;
@@ -1212,7 +1212,7 @@ struct Elf64Ehdr {
 };
 
 struct Elf32Ehdr {
-  u8 e_ident[16];
+  u8 e_ident[16] = {};
   ul16 e_type;
   ul16 e_machine;
   ul32 e_version;
@@ -1258,7 +1258,7 @@ struct Elf64Rel {
 
 struct Elf32Rel {
   ul32 r_offset;
-  u8 r_type;
+  u8 r_type = 0;
   ul24 r_sym;
 };
 
@@ -1271,7 +1271,7 @@ struct Elf64Rela {
 
 struct Elf32Rela {
   ul32 r_offset;
-  u8 r_type;
+  u8 r_type = 0;
   ul24 r_sym;
   il32 r_addend;
 };
diff --git a/elf/passes.cc b/elf/passes.cc
index c172b7a363..8c88d6f4b0 100644
--- a/elf/passes.cc
+++ b/elf/passes.cc
@@ -363,7 +363,7 @@ ObjectFile<E> *create_internal_file(Context<E> &ctx) {
   obj->priority = 1;
 
   auto add = [&](std::string_view name, u8 st_type = STT_NOTYPE) {
-    ElfSym<E> esym = {};
+    ElfSym<E> esym;
     esym.st_type = st_type;
     esym.st_shndx = SHN_ABS;
     esym.st_bind = STB_GLOBAL;
@@ -429,7 +429,7 @@ ObjectFile<E> *create_internal_file(Context<E> &ctx) {
 
   for (i64 i = 0; i < ctx.arg.defsyms.size(); i++) {
     Symbol<E> *sym = ctx.arg.defsyms[i].first;
-    ElfSym<E> esym = {};
+    ElfSym<E> esym;
     esym.st_type = STT_NOTYPE;
     esym.st_shndx = SHN_ABS;
     esym.st_bind = STB_GLOBAL;