IntelFrameworkModulePkg: Refine type cast for pointer subtraction

For pointer subtraction, the result is of type "ptrdiff_t". According to
the C11 standard (Committee Draft - April 12, 2011):

"When two pointers are subtracted, both shall point to elements of the
same array object, or one past the last element of the array object; the
result is the difference of the subscripts of the two array elements. The
size of the result is implementation-defined, and its type (a signed
integer type) is ptrdiff_t defined in the <stddef.h> header. If the result
is not representable in an object of that type, the behavior is
undefined."

In our codes, there are cases that the pointer subtraction is not
performed by pointers to elements of the same array object. This might
lead to potential issues, since the behavior is undefined according to C11
standard.

Also, since the size of type "ptrdiff_t" is implementation-defined. Some
static code checkers may warn that the pointer subtraction might underflow
first and then being cast to a bigger size. For example:

UINT8  *Ptr1, *Ptr2;
UINTN  PtrDiff;
...
PtrDiff = (UINTN) (Ptr1 - Ptr2);

The commit will refine the pointer subtraction expressions by casting each
pointer to UINTN first and then perform the subtraction:

PtrDiff = (UINTN) Ptr1 - (UINTN) Ptr2;

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>

6 files changed, 13 insertions, 13 deletions

diff --git a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
index 8f91a7d7a9..c4c77ec344 100644
--- a/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
+++ b/IntelFrameworkModulePkg/Csm/LegacyBiosDxe/LegacyPci.c
@@ -1,6 +1,6 @@
 /** @file

 

-Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>

+Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>

 

 This program and the accompanying materials

 are licensed and made available under the terms and conditions

@@ -318,7 +318,7 @@ GetPciLegacyRom (
       break;

     }

 

-    if ((UINTN)(RomHeader.Raw - (UINT8 *) *Rom) + Pcir->ImageLength * 512 > *ImageSize) {

+    if (((UINTN)RomHeader.Raw - (UINTN)*Rom) + Pcir->ImageLength * 512 > *ImageSize) {

       break;

     }

     

diff --git a/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsBoot.c b/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsBoot.c
index bba62a801a..628424d0e5 100644
--- a/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsBoot.c
+++ b/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsBoot.c
@@ -1,7 +1,7 @@
 /** @file

   BDS Lib functions which relate with create or process the boot option.

 

-Copyright (c) 2004 - 2016, Intel Corporation. All rights reserved.<BR>

+Copyright (c) 2004 - 2017, Intel Corporation. All rights reserved.<BR>

 This program and the accompanying materials

 are licensed and made available under the terms and conditions of the BSD License

 which accompanies this distribution.  The full text of the license may be found at

@@ -1034,7 +1034,7 @@ BdsCreateDevOrder (
   DevOrderPtr->Length  = (UINT16) (sizeof (UINT16) + BEVCount * sizeof (UINT16));

   DevOrderPtr          = (LEGACY_DEV_ORDER_ENTRY *) BdsFillDevOrderBuf (BbsTable, BBS_BEV_DEVICE, BbsCount, DevOrderPtr->Data);

 

-  ASSERT (TotalSize == (UINTN) ((UINT8 *) DevOrderPtr - (UINT8 *) DevOrder));

+  ASSERT (TotalSize == ((UINTN) DevOrderPtr - (UINTN) DevOrder));

 

   //

   // Save device order for legacy boot device to variable.

diff --git a/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsConsole.c b/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsConsole.c
index 1020e84c3d..8f273ff1b1 100644
--- a/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsConsole.c
+++ b/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsConsole.c
@@ -1,7 +1,7 @@
 /** @file

   BDS Lib functions which contain all the code to connect console device

 

-Copyright (c) 2004 - 2014, Intel Corporation. All rights reserved.<BR>

+Copyright (c) 2004 - 2017, Intel Corporation. All rights reserved.<BR>

 This program and the accompanying materials

 are licensed and made available under the terms and conditions of the BSD License

 which accompanies this distribution.  The full text of the license may be found at

@@ -873,7 +873,7 @@ ConvertBmpToGopBlt (
 

     }

 

-    ImageIndex = (UINTN) (Image - ImageHeader);

+    ImageIndex = (UINTN)Image - (UINTN)ImageHeader;

     if ((ImageIndex % 4) != 0) {

       //

       // Bmp Image starts each row on a 32-bit boundary!

diff --git a/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsMisc.c b/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsMisc.c
index 24c1998a14..2ba511aada 100644
--- a/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsMisc.c
+++ b/IntelFrameworkModulePkg/Library/GenericBdsLib/BdsMisc.c
@@ -1,7 +1,7 @@
 /** @file

   Misc BDS library function

 

-Copyright (c) 2004 - 2015, Intel Corporation. All rights reserved.<BR>

+Copyright (c) 2004 - 2017, Intel Corporation. All rights reserved.<BR>

 This program and the accompanying materials

 are licensed and made available under the terms and conditions of the BSD License

 which accompanies this distribution.  The full text of the license may be found at

@@ -669,7 +669,7 @@ BdsLibVariableToOption (
   // Get load opion data.

   //

   LoadOptions     = TempPtr;

-  LoadOptionsSize = (UINT32) (VariableSize - (UINTN) (TempPtr - Variable));

+  LoadOptionsSize = (UINT32) (VariableSize - ((UINTN)TempPtr - (UINTN)Variable));

 

   //

   // The Console variables may have multiple device paths, so make

diff --git a/IntelFrameworkModulePkg/Library/LegacyBootManagerLib/LegacyBm.c b/IntelFrameworkModulePkg/Library/LegacyBootManagerLib/LegacyBm.c
index c56a878639..080a436c71 100644
--- a/IntelFrameworkModulePkg/Library/LegacyBootManagerLib/LegacyBm.c
+++ b/IntelFrameworkModulePkg/Library/LegacyBootManagerLib/LegacyBm.c
@@ -3,7 +3,7 @@
   and manage the legacy boot option, all legacy boot option is getting from

   the legacy BBS table.

 

-Copyright (c) 2011 - 2016, Intel Corporation. All rights reserved.<BR>

+Copyright (c) 2011 - 2017, Intel Corporation. All rights reserved.<BR>

 This program and the accompanying materials

 are licensed and made available under the terms and conditions of the BSD License

 which accompanies this distribution.  The full text of the license may be found at

@@ -725,7 +725,7 @@ LegacyBmCreateDevOrder (
   DevOrderPtr->Length  = (UINT16) (sizeof (UINT16) + BEVCount * sizeof (UINT16));

   DevOrderPtr          = (LEGACY_DEV_ORDER_ENTRY *) LegacyBmFillDevOrderBuf (BbsTable, BBS_BEV_DEVICE, BbsCount, DevOrderPtr->Data);

 

-  ASSERT (TotalSize == (UINTN) ((UINT8 *) DevOrderPtr - (UINT8 *) DevOrder));

+  ASSERT (TotalSize == ((UINTN) DevOrderPtr - (UINTN) DevOrder));

 

   //

   // Save device order for legacy boot device to variable.

diff --git a/IntelFrameworkModulePkg/Universal/BdsDxe/BootMaint/BootOption.c b/IntelFrameworkModulePkg/Universal/BdsDxe/BootMaint/BootOption.c
index 5898fb31bb..6233a1145a 100644
--- a/IntelFrameworkModulePkg/Universal/BdsDxe/BootMaint/BootOption.c
+++ b/IntelFrameworkModulePkg/Universal/BdsDxe/BootMaint/BootOption.c
@@ -5,7 +5,7 @@
 

   Boot option manipulation

 

-Copyright (c) 2004 - 2015, Intel Corporation. All rights reserved.<BR>

+Copyright (c) 2004 - 2017, Intel Corporation. All rights reserved.<BR>

 This program and the accompanying materials

 are licensed and made available under the terms and conditions of the BSD License

 which accompanies this distribution.  The full text of the license may be found at

@@ -1124,7 +1124,7 @@ BOpt_AppendFileName (
       // that overlap.

       //

       StrCpyS (TmpStr, MaxLen, Ptr + 3);

-      StrCpyS (LastSlash, MaxLen - (UINTN) (LastSlash - Str), TmpStr);

+      StrCpyS (LastSlash, MaxLen - ((UINTN) LastSlash - (UINTN) Str) / sizeof (CHAR16), TmpStr);

       Ptr = LastSlash;

     } else if (*Ptr == '\\' && *(Ptr + 1) == '.' && *(Ptr + 2) == '\\') {

       //

@@ -1136,7 +1136,7 @@ BOpt_AppendFileName (
       // that overlap.

       //

       StrCpyS (TmpStr, MaxLen, Ptr + 2);

-      StrCpyS (Ptr, MaxLen - (UINTN) (Ptr - Str), TmpStr);

+      StrCpyS (Ptr, MaxLen - ((UINTN) Ptr - (UINTN) Str) / sizeof (CHAR16), TmpStr);

       Ptr = LastSlash;

     } else if (*Ptr == '\\') {

       LastSlash = Ptr;