Re: [PATCH 3/5] MdeModulePkg/UdfDxe: replace zero-init of local variables with ZeroMem()

["Zeng, Star" <star.zeng@intel.com>]

Reviewed-by: Star Zeng <star.zeng@intel.com>

BTW: How about to use "sizeof ()" instead of "sizeof"?


Thanks,
Star
-----Original Message-----
From: Laszlo Ersek [mailto:lersek@redhat.com] 
Sent: Sunday, September 10, 2017 8:13 AM
To: edk2-devel-01 <edk2-devel@lists.01.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>; Dong, Eric <eric.dong@intel.com>; Paulo Alcantara <pcacjr@zytor.com>; Ni, Ruiyu <ruiyu.ni@intel.com>; Zeng, Star <star.zeng@intel.com>
Subject: [PATCH 3/5] MdeModulePkg/UdfDxe: replace zero-init of local variables with ZeroMem()

In edk2, initialization of local variables is forbidden, both for stylistic reasons and because such initialization may generate calls to compiler intrinsics.

For the following initialization in UdfRead():

  CHAR16                          FileName[UDF_FILENAME_LENGTH] = { 0 };

clang-3.8 generates a memset() call, when building UdfDxe for IA32, which then fails to link.

Replace the initialization with ZeroMem().

Do the same to "FilePath" in UdfOpen().

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Paulo Alcantara <pcacjr@zytor.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
 MdeModulePkg/Universal/Disk/UdfDxe/File.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/File.c b/MdeModulePkg/Universal/Disk/UdfDxe/File.c
index 8b9339567f8e..e7159ff861f7 100644
--- a/MdeModulePkg/Universal/Disk/UdfDxe/File.c
+++ b/MdeModulePkg/Universal/Disk/UdfDxe/File.c
@@ -174,15 +174,16 @@ UdfOpen (
 {
   EFI_TPL                     OldTpl;
   EFI_STATUS                  Status;
   PRIVATE_UDF_FILE_DATA       *PrivFileData;
   PRIVATE_UDF_SIMPLE_FS_DATA  *PrivFsData;
-  CHAR16                      FilePath[UDF_PATH_LENGTH] = { 0 };
+  CHAR16                      FilePath[UDF_PATH_LENGTH];
   UDF_FILE_INFO               File;
   PRIVATE_UDF_FILE_DATA       *NewPrivFileData;
   CHAR16                      *TempFileName;
 
+  ZeroMem (FilePath, sizeof FilePath);
   OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
 
   if (This == NULL || NewHandle == NULL || FileName == NULL) {
     Status = EFI_INVALID_PARAMETER;
     goto Error_Invalid_Params;
@@ -322,14 +323,15 @@ UdfRead (
   EFI_BLOCK_IO_PROTOCOL           *BlockIo;
   EFI_DISK_IO_PROTOCOL            *DiskIo;
   UDF_FILE_INFO                   FoundFile;
   UDF_FILE_IDENTIFIER_DESCRIPTOR  *NewFileIdentifierDesc;
   VOID                            *NewFileEntryData;
-  CHAR16                          FileName[UDF_FILENAME_LENGTH] = { 0 };
+  CHAR16                          FileName[UDF_FILENAME_LENGTH];
   UINT64                          FileSize;
   UINT64                          BufferSizeUint64;
 
+  ZeroMem (FileName, sizeof FileName);
   OldTpl = gBS->RaiseTPL (TPL_CALLBACK);
 
   if (This == NULL || BufferSize == NULL || (*BufferSize != 0 &&
                                              Buffer == NULL)) {
     Status = EFI_INVALID_PARAMETER;
--
2.14.1.3.gb7cf6e02401b