Zero-init or void-init most char arrays

dlang · Jan 4, 2019 · c322ec4 · c322ec4
1 parent 29e9ac2
commit c322ec4
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Showing 78 changed files with 576 additions and 573 deletions.
diff --git a/changelog/zero_init.dd b/changelog/zero_init.dd
@@ -0,0 +1,3 @@
+`char`/`wchar` fields in most D runtime (`core.*` and `rt.*`) structs are now zero-initialized
+
+Fields that are single `char`/wchar` or fixed-length arrays of such are now initialized to all zero bits instead of all one bits for most structs in the D runtime (`core.*` and `rt.*` modules). This simplifies initialization and removes the need to store init data when it makes the entire struct zero-initialized. Most affected structs are used for interoperability with C APIs.
diff --git a/src/core/cpuid.d b/src/core/cpuid.d
@@ -320,8 +320,8 @@ struct CpuFeatures
     bool probablyIntel; // true = _probably_ an Intel processor, might be faking
     bool probablyAMD; // true = _probably_ an AMD processor
     string processorName;
-    char [12] vendorID;
-    char [48] processorNameBuffer;
+    char [12] vendorID = 0;
+    char [48] processorNameBuffer = 0;
     uint features = 0;     // mmx, sse, sse2, hyperthreading, etc
     uint miscfeatures = 0; // sse3, etc.
     uint extfeatures = 0;  // HLE, AVX2, RTM, etc.

diff --git a/src/core/internal/utf.d b/src/core/internal/utf.d
@@ -447,7 +447,7 @@ void encode(ref char[] s, dchar c)
         }
         else
         {
-            char[4] buf;
+            char[4] buf = void;
             uint L;
 
             if (c <= 0x7FF)
@@ -516,7 +516,7 @@ void encode(ref wchar[] s, dchar c)
         }
         else
         {
-            wchar[2] buf;
+            wchar[2] buf = void;
 
             buf[0] = cast(wchar) ((((c - 0x10000) >> 10) & 0x3FF) + 0xD800);
             buf[1] = cast(wchar) (((c - 0x10000) & 0x3FF) + 0xDC00);

diff --git a/src/core/runtime.d b/src/core/runtime.d
@@ -823,7 +823,7 @@ Throwable.TraceInfo defaultTraceHandler( void* ptr = null )
                     int ret = 0;
                     for ( int i = FIRSTFRAME; i < numframes; ++i )
                     {
-                        char[4096] fixbuf;
+                        char[4096] fixbuf = void;
                         auto buf = framelist[i][0 .. strlen(framelist[i])];
                         auto pos = cast(size_t)(i - FIRSTFRAME);
                         buf = fixline( buf, fixbuf );

diff --git a/src/core/stdc/stdio.d b/src/core/stdc/stdio.d
@@ -201,7 +201,7 @@ else version (FreeBSD)
 
     union __mbstate_t // <sys/_types.h>
     {
-        char[128]   _mbstate8;
+        char[128]   _mbstate8 = 0;
         long        _mbstateL;
     }
 }
@@ -231,7 +231,7 @@ else version (NetBSD)
 
     union __mbstate_t // <sys/_types.h>
     {
-        char[128]   _mbstate8;
+        char[128]   _mbstate8 = 0;
         long        _mbstateL;
     }
 }
@@ -261,7 +261,7 @@ else version (OpenBSD)
 
     union __mbstate_t // <sys/_types.h>
     {
-        char[128]   __mbstate8;
+        char[128]   __mbstate8 = 0;
         long        __mbstateL;
     }
 }
@@ -300,7 +300,7 @@ else version (DragonFlyBSD)
 
     union __mbstate_t                   // <sys/stdint.h>
     {
-        char[128]   _mbstate8;
+        char[128]   _mbstate8 = 0;
         long        _mbstateL;
     }
 }
@@ -453,7 +453,7 @@ else version (CRuntime_Glibc)
         int     _old_offset;
         ushort  _cur_column;
         byte    _vtable_offset;
-        char[1] _shortbuf;
+        char[1] _shortbuf = 0;
         void*   _lock;
     }
 
@@ -466,7 +466,7 @@ else version (CRuntime_Musl)
 {
     union fpos_t
     {
-        char[16] __opaque;
+        char[16] __opaque = 0;
         double __align;
     }
     struct _IO_FILE;
@@ -593,7 +593,7 @@ else version (NetBSD)
 
         int     function(void *)    _flush;
         /* Formerly used by fgetln/fgetwln; kept for binary compatibility */
-        char[__sbuf.sizeof - _flush.sizeof]    _lb_unused;
+        char[__sbuf.sizeof - _flush.sizeof]    _lb_unused = void;
 
 
         int             _blksize;
@@ -696,8 +696,8 @@ else version (Solaris)
             char* _ptr;
             int _cnt;
             char* _base;
-            char _flag;
-            char _magic;
+            char _flag = 0;
+            char _magic = 0;
             ushort __flags; // __orientation:2
                             // __ionolock:1
                             // __seekable:1
@@ -780,7 +780,7 @@ else version (CRuntime_UClibc)
     struct __STDIO_FILE_STRUCT
     {
         ushort __modeflags;
-        char[2] __ungot_width;
+        char[2] __ungot_width = 0;
         int __filedes;
         char* __bufstart;
         char* __bufend;
@@ -791,7 +791,7 @@ else version (CRuntime_UClibc)
         __STDIO_FILE_STRUCT* __nextopen;
         void *__cookie;
         _IO_cookie_io_functions_t __gcs;
-        wchar_t[2] __ungot;
+        wchar_t[2] __ungot = 0;
         mbstate_t __state;
         void *__unused;
         int __user_locking;

diff --git a/src/core/stdc/wchar_.d b/src/core/stdc/wchar_.d
@@ -34,7 +34,7 @@ version (CRuntime_Glibc)
         int __count;
         union ___value
         {
-            wint_t __wch;
+            wint_t __wch = 0;
             char[4] __wchb;
         }
         ___value __value;
@@ -44,7 +44,7 @@ else version (OpenBSD)
 {
     union __mbstate_t
     {
-        char[128] __mbstate8;
+        char[128] __mbstate8 = 0;
         int64_t   __mbstateL;
     }
     alias mbstate_t = __mbstate_t;
@@ -69,8 +69,8 @@ else version (CRuntime_UClibc)
     ///
     struct mbstate_t
     {
-        wchar_t __mask;
-        wchar_t __wc;
+        wchar_t __mask = 0;
+        wchar_t __wc = 0;
     }
 }
 else

diff --git a/src/core/sys/darwin/mach/loader.d b/src/core/sys/darwin/mach/loader.d
@@ -144,7 +144,7 @@ version (CoreDdoc)
         uint cmdsize;
 
         /// The name of this segment.
-        char[16] segname;
+        char[16] segname = 0;
 
         /// Memory address of this segment.
         uint vmaddr;
@@ -181,7 +181,7 @@ version (CoreDdoc)
         uint cmdsize;
 
         /// The name of this segment.
-        char[16] segname;
+        char[16] segname = 0;
 
         /// Memory address of this segment.
         long vmaddr;
@@ -212,10 +212,10 @@ version (CoreDdoc)
     struct section
     {
         /// The name of this this section.
-        char[16] sectname;
+        char[16] sectname = 0;
 
         /// The name of the segment this section belongs to.
-        char[16] segname;
+        char[16] segname = 0;
 
         /// The memory address of this section.
         uint addr;
@@ -249,10 +249,10 @@ version (CoreDdoc)
     struct section_64
     {
         /// The name of this this section.
-        char[16] sectname;
+        char[16] sectname = 0;
 
         /// The name of the segment this section belongs to.
-        char[16] segname;
+        char[16] segname = 0;
 
         /// The memory address of this section.
         ulong addr;
@@ -351,7 +351,7 @@ struct segment_command
 {
     uint cmd;
     uint cmdsize;
-    char[16] segname;
+    char[16] segname = 0;
     uint vmaddr;
     uint vmsize;
     uint fileoff;
@@ -366,7 +366,7 @@ struct segment_command_64
 {
     uint cmd;
     uint cmdsize;
-    char[16] segname;
+    char[16] segname = 0;
     long vmaddr;
     long vmsize;
     long fileoff;
@@ -379,8 +379,8 @@ struct segment_command_64
 
 struct section
 {
-    char[16] sectname;
-    char[16] segname;
+    char[16] sectname = 0;
+    char[16] segname = 0;
     uint     addr;
     uint     size;
     uint     offset;
@@ -394,8 +394,8 @@ struct section
 
 struct section_64
 {
-    char[16] sectname;
-    char[16] segname;
+    char[16] sectname = 0;
+    char[16] segname = 0;
     ulong    addr;
     ulong    size;
     uint     offset;

diff --git a/src/core/sys/darwin/netinet/in_.d b/src/core/sys/darwin/netinet/in_.d
@@ -224,7 +224,7 @@ static if (_DARWIN_C_SOURCE)
     struct ip_opts
     {
         in_addr  ip_dst;
-        char[40] ip_opts;
+        char[40] ip_opts = 0;
     };
 
     enum IP_OPTIONS         = 1;

diff --git a/src/core/sys/dragonflybsd/sys/elf32.d b/src/core/sys/dragonflybsd/sys/elf32.d
@@ -25,7 +25,7 @@ alias Elf32_Sword Elf32_Ssize;
 
 struct Elf32_Ehdr
 {
-    char[EI_NIDENT] e_ident;
+    char[EI_NIDENT] e_ident = 0;
     Elf32_Half    e_type;
     Elf32_Half    e_machine;
     Elf32_Word    e_version;

diff --git a/src/core/sys/dragonflybsd/sys/elf64.d b/src/core/sys/dragonflybsd/sys/elf64.d
@@ -27,7 +27,7 @@ alias Elf64_Sxword Elf64_Ssize;
 
 struct Elf64_Ehdr
 {
-    char[EI_NIDENT] e_ident;
+    char[EI_NIDENT] e_ident = 0;
     Elf64_Half    e_type;
     Elf64_Half    e_machine;
     Elf64_Word    e_version;

diff --git a/src/core/sys/freebsd/sys/elf32.d b/src/core/sys/freebsd/sys/elf32.d
@@ -25,7 +25,7 @@ alias Elf32_Sword Elf32_Ssize;
 
 struct Elf32_Ehdr
 {
-    char[EI_NIDENT] e_ident;
+    char[EI_NIDENT] e_ident = 0;
     Elf32_Half    e_type;
     Elf32_Half    e_machine;
     Elf32_Word    e_version;

diff --git a/src/core/sys/freebsd/sys/elf64.d b/src/core/sys/freebsd/sys/elf64.d
@@ -27,7 +27,7 @@ alias Elf64_Sxword Elf64_Ssize;
 
 struct Elf64_Ehdr
 {
-    char[EI_NIDENT] e_ident;
+    char[EI_NIDENT] e_ident = 0;
     Elf64_Half    e_type;
     Elf64_Half    e_machine;
     Elf64_Word    e_version;

diff --git a/src/core/sys/freebsd/sys/mount.d b/src/core/sys/freebsd/sys/mount.d
@@ -28,7 +28,7 @@ struct fid
 {
     ushort         fid_len;
     ushort         fid_data0;
-    char[MAXFIDSZ] fid_data;
+    char[MAXFIDSZ] fid_data = 0;
 }
 
 enum MFSNAMELEN = 16;
@@ -55,10 +55,10 @@ struct statfs_t
     uint f_namemax;
     uid_t f_owner;
     fsid_t f_fsid;
-    char[80] f_charspare;
-    char[MFSNAMELEN] f_fstypename;
-    char[MNAMELEN] f_mntfromname;
-    char[MNAMELEN] f_mntonname;
+    char[80] f_charspare = 0;
+    char[MFSNAMELEN] f_fstypename = 0;
+    char[MNAMELEN] f_mntfromname = 0;
+    char[MNAMELEN] f_mntonname = 0;
 }
 
 
@@ -207,7 +207,7 @@ struct nfs_public
 struct vfsconf
 {
     uint vfc_version;
-    char[MFSNAMELEN] vfc_name;
+    char[MFSNAMELEN] vfc_name = 0;
     vfsops* vfc_vfsops;
     int vfc_typenum;
     int vfc_refcount;
@@ -219,7 +219,7 @@ struct vfsconf
 struct xvfsconf
 {
     vfsops* vfc_vfsops;
-    char[MFSNAMELEN] vfc_name;
+    char[MFSNAMELEN] vfc_name = 0;
     int vfc_typenum;
     int vfc_refcount;
     int vfc_flags;
@@ -230,7 +230,7 @@ struct xvfsconf
 struct ovfsconf
 {
     void* vfc_vfsops;
-    char[32] vfc_name;
+    char[32] vfc_name = 0;
     int vfc_index;
     int vfc_refcount;
     int vfc_flags;
@@ -252,7 +252,7 @@ struct vfsidctl
 {
     int vc_vers;
     fsid_t vc_fsid;
-    char[MFSNAMELEN] vc_fstypename;
+    char[MFSNAMELEN] vc_fstypename = 0;
     fsctlop_t vc_op;
     void* vc_ptr;
     size_t vc_len;

diff --git a/src/core/sys/linux/elf.d b/src/core/sys/linux/elf.d
@@ -42,7 +42,7 @@ enum EI_NIDENT = 16;
 
 struct Elf32_Ehdr
 {
-    char[EI_NIDENT] e_ident;
+    char[EI_NIDENT] e_ident = 0;
     Elf32_Half    e_type;
     Elf32_Half    e_machine;
     Elf32_Word    e_version;
@@ -60,7 +60,7 @@ struct Elf32_Ehdr
 
 struct Elf64_Ehdr
 {
-    char[EI_NIDENT] e_ident;
+    char[EI_NIDENT] e_ident = 0;
     Elf64_Half    e_type;
     Elf64_Half    e_machine;
     Elf64_Word    e_version;

diff --git a/src/core/sys/linux/netinet/in_.d b/src/core/sys/linux/netinet/in_.d
@@ -312,7 +312,7 @@ version (linux_libc)
         struct ip_opts
         {
             in_addr ip_dst;
-            char[40] ip_opts;
+            char[40] ip_opts = 0;
         };
 
         struct ip_mreqn

diff --git a/src/core/sys/netbsd/sys/elf32.d b/src/core/sys/netbsd/sys/elf32.d
@@ -25,7 +25,7 @@ alias Elf32_Sword Elf32_Ssize;
 
 struct Elf32_Ehdr
 {
-    char[EI_NIDENT] e_ident;
+    char[EI_NIDENT] e_ident = 0;
     Elf32_Half    e_type;
     Elf32_Half    e_machine;
     Elf32_Word    e_version;

diff --git a/src/core/sys/netbsd/sys/elf64.d b/src/core/sys/netbsd/sys/elf64.d
@@ -27,7 +27,7 @@ alias Elf64_Sxword Elf64_Ssize;
 
 struct Elf64_Ehdr
 {
-    char[EI_NIDENT] e_ident;
+    char[EI_NIDENT] e_ident = 0;
     Elf64_Half    e_type;
     Elf64_Half    e_machine;
     Elf64_Word    e_version;