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author | Hao Wu <hao.a.wu@intel.com> | 2017-01-23 11:24:50 +0800 |
---|---|---|
committer | Hao Wu <hao.a.wu@intel.com> | 2017-03-06 14:33:22 +0800 |
commit | aa5f60ae41f0fa1b4816071704ab6669b0fe94c1 (patch) | |
tree | 0128741729b8c42cbc90c73e242a69b4c0833fd3 /IntelFrameworkModulePkg/Universal/CpuIoDxe | |
parent | 64b25f5db17c3b16d2a898095a4a205404126b49 (diff) | |
download | edk2-aa5f60ae41f0fa1b4816071704ab6669b0fe94c1.tar.gz edk2-aa5f60ae41f0fa1b4816071704ab6669b0fe94c1.tar.bz2 edk2-aa5f60ae41f0fa1b4816071704ab6669b0fe94c1.zip |
IntelFrameworkModulePkg: 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: Jeff Fan <jeff.fan@intel.com>
Diffstat (limited to 'IntelFrameworkModulePkg/Universal/CpuIoDxe')
-rw-r--r-- | IntelFrameworkModulePkg/Universal/CpuIoDxe/CpuIo.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/IntelFrameworkModulePkg/Universal/CpuIoDxe/CpuIo.c b/IntelFrameworkModulePkg/Universal/CpuIoDxe/CpuIo.c index 9db9dbe974..9474606e20 100644 --- a/IntelFrameworkModulePkg/Universal/CpuIoDxe/CpuIo.c +++ b/IntelFrameworkModulePkg/Universal/CpuIoDxe/CpuIo.c @@ -1,7 +1,7 @@ /** @file
Uses the services of the I/O Library to produce the CPU I/O Protocol
-Copyright (c) 2004 - 2012, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2004 - 2017, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2017, AMD Incorporated. All rights reserved.<BR>
This program and the accompanying materials
@@ -141,7 +141,7 @@ CpuIoCheckParameter ( //
// Check to see if Address is aligned
//
- if ((Address & (UINT64)(mInStride[Width] - 1)) != 0) {
+ if ((Address & ((UINT64)mInStride[Width] - 1)) != 0) {
return EFI_UNSUPPORTED;
}
|