On 09/13/17 08:43, Zeng, Star wrote: > Beyond the Rb (I do not want to block this patch series), I am curious about > one question. > > There may be more this kind of workarounds to fix the build failure. > Is it possible to disable the warning (like below example for VS) for > specific version of GCC for this kind of false alarm? > > > ProcessorBind.h: > #if defined(_MSC_EXTENSIONS) > > ... > > #if _MSC_VER == 1800 || _MSC_VER == 1900 > > // > // Disable these warnings for VS2013. > // > > // > // This warning is for potentially uninitialized local variable, and it may > cause false > // positive issues in VS2013 and VS2015 build > // > #pragma warning ( disable : 4701 ) > > // > // This warning is for potentially uninitialized local pointer variable, and > it may cause > // false positive issues in VS2013 and VS2015 build > // > #pragma warning ( disable : 4703 ) > > #endif > > #endif
I think starting with gcc-4.6, gcc supports the "diagnostics" pragma, which can be used to suppress warnings. Unfortunately, there's no pragma to suppress *only* the incorrect warnings :) So if we set the pragma, we could lose even those warnings that point out real bugs. Thanks Laszlo > > > Thanks, > Star > -----Original Message----- > From: Zeng, Star > Sent: Wednesday, September 13, 2017 2:34 PM > To: Laszlo Ersek <[email protected]>; edk2-devel-01 <[email protected]> > Cc: Ard Biesheuvel <[email protected]>; Dong, Eric > <[email protected]>; Paulo Alcantara <[email protected]>; Ni, Ruiyu > <[email protected]>; Zeng, Star <[email protected]> > Subject: RE: [PATCH 2/2] MdeModulePkg/UdfDxe: suppress incorrect compiler > warning in ReadFile() > > Reviewed-by: Star Zeng <[email protected]> > > -----Original Message----- > From: Laszlo Ersek [mailto:[email protected]] > Sent: Wednesday, September 13, 2017 6:26 AM > To: edk2-devel-01 <[email protected]> > Cc: Ard Biesheuvel <[email protected]>; Dong, Eric > <[email protected]>; Paulo Alcantara <[email protected]>; Ni, Ruiyu > <[email protected]>; Zeng, Star <[email protected]> > Subject: [PATCH 2/2] MdeModulePkg/UdfDxe: suppress incorrect compiler warning > in ReadFile() > > When building the driver for DEBUG/RELEASE, GCC48/GCC49 warn about > ReadFile() possibly using "BytesLeft" without initializing it first. > > This is not the case. The reads of "BytesLeft" are only reachable if > (ReadFileInfo->Flags == READ_FILE_SEEK_AND_READ). But, in that case, we also > set "BytesLeft" to "ReadFileInfo->FileDataSize", near the top of the function. > > Assign "BytesLeft" zero at the top, and add a comment that conforms to the > pending Coding Style Spec feature request at > <https://bugzilla.tianocore.org/show_bug.cgi?id=607>. > > This issue was reported by Ard's and Gerd's CI systems independently. > > Cc: Ard Biesheuvel <[email protected]> > Cc: Eric Dong <[email protected]> > Cc: Paulo Alcantara <[email protected]> > Cc: Ruiyu Ni <[email protected]> > Cc: Star Zeng <[email protected]> > Reported-by: Ard Biesheuvel <[email protected]> > Reported-by: Gerd Hoffmann <[email protected]> > Contributed-under: TianoCore Contribution Agreement 1.1 > Signed-off-by: Laszlo Ersek <[email protected]> > --- > MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c > b/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c > index 096fbb4452cb..392494b2eb3f 100644 > --- a/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c > +++ b/MdeModulePkg/Universal/Disk/UdfDxe/FileSystemOperations.c > @@ -893,6 +893,11 @@ ReadFile ( > LogicalBlockSize = LV_BLOCK_SIZE (Volume, UDF_DEFAULT_LV_NUM); > DoFreeAed = FALSE; > > + // > + // set BytesLeft to suppress incorrect compiler/analyzer warnings // > + BytesLeft = 0; > + > switch (ReadFileInfo->Flags) { > case READ_FILE_GET_FILESIZE: > case READ_FILE_ALLOCATE_AND_READ: > -- > 2.14.1.3.gb7cf6e02401b > _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
