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authorHao Wu <hao.a.wu@intel.com>2017-02-24 10:01:34 +0800
committerHao Wu <hao.a.wu@intel.com>2017-03-06 14:33:20 +0800
commit16f6922709952c7ad468dcdee6ef94b3e5a3cd90 (patch)
tree999456e2e6812457d5c0b32b969ac0eed2b02149 /MdeModulePkg/Universal/FaultTolerantWriteDxe
parent95ba3d92dca2616715e2af89d2bbeca9577a3e2c (diff)
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MdeModulePkg: Refine casting expression result to bigger size
There are cases that the operands of an expression are all with rank less than UINT64/INT64 and the result of the expression is explicitly cast to UINT64/INT64 to fit the target size. An example will be: UINT32 a,b; // a and b can be any unsigned int type with rank less than UINT64, like // UINT8, UINT16, etc. UINT64 c; c = (UINT64) (a + b); Some static code checkers may warn that the expression result might overflow within the rank of "int" (integer promotions) and the result is then cast to a bigger size. The commit refines codes by the following rules: 1). When the expression is possible to overflow the range of unsigned int/ int: c = (UINT64)a + b; 2). When the expression will not overflow within the rank of "int", remove the explicit type casts: c = a + b; 3). When the expression will be cast to pointer of possible greater size: UINT32 a,b; VOID *c; c = (VOID *)(UINTN)(a + b); --> c = (VOID *)((UINTN)a + b); 4). When one side of a comparison expression contains only operands with rank less than UINT32: UINT8 a; UINT16 b; UINTN c; if ((UINTN)(a + b) > c) {...} --> if (((UINT32)a + b) > c) {...} For rule 4), if we remove the 'UINTN' type cast like: if (a + b > c) {...} The VS compiler will complain with warning C4018 (signed/unsigned mismatch, level 3 warning) due to promoting 'a + b' to type 'int'. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Hao Wu <hao.a.wu@intel.com> Reviewed-by: Feng Tian <feng.tian@intel.com>
Diffstat (limited to 'MdeModulePkg/Universal/FaultTolerantWriteDxe')
-rw-r--r--MdeModulePkg/Universal/FaultTolerantWriteDxe/UpdateWorkingBlock.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/MdeModulePkg/Universal/FaultTolerantWriteDxe/UpdateWorkingBlock.c b/MdeModulePkg/Universal/FaultTolerantWriteDxe/UpdateWorkingBlock.c
index d46a37fde3..b4327b5619 100644
--- a/MdeModulePkg/Universal/FaultTolerantWriteDxe/UpdateWorkingBlock.c
+++ b/MdeModulePkg/Universal/FaultTolerantWriteDxe/UpdateWorkingBlock.c
@@ -2,7 +2,7 @@
Internal functions to operate Working Block Space.
-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 of the BSD License
which accompanies this distribution. The full text of the license may be found at
@@ -55,7 +55,7 @@ InitializeLocalWorkSpaceHeader (
&gEdkiiWorkingBlockSignatureGuid,
sizeof (EFI_GUID)
);
- mWorkingBlockHeader.WriteQueueSize = (UINT64) (PcdGet32 (PcdFlashNvStorageFtwWorkingSize) - sizeof (EFI_FAULT_TOLERANT_WORKING_BLOCK_HEADER));
+ mWorkingBlockHeader.WriteQueueSize = PcdGet32 (PcdFlashNvStorageFtwWorkingSize) - sizeof (EFI_FAULT_TOLERANT_WORKING_BLOCK_HEADER);
//
// Crc is calculated with all the fields except Crc and STATE, so leave them as FTW_ERASED_BYTE.