<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"><base href="x-msg://286/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>Hi, Dennis. In general, static analyzer bugs should be reported through <a href="http://llvm.org/bugs/">http://llvm.org/bugs/</a>, under clang / Static Analyzer. In this case, though, the issue isn't the bitfields but the "reinterpret_cast" of the UINT32 into a struct. This is a known issue, tracked in <a href="http://llvm.org/bugs/show_bug.cgi?id=13919">PR13919</a> and <<a href="rdar://problem/11966749">rdar://problem/11966749</a>>. I'd suggest attaching a preprocessed file to the PR to make sure we check against your test case when we do get around to fixing this.</div><div><br></div><div>Thanks for the report,</div><div>Jordan</div><div><br></div><br><div><div>On Apr 16, 2013, at 14:30 , Dennis Cote <<a href="mailto:DennisC@harding.ca">DennisC@harding.ca</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div lang="EN-CA" link="blue" vlink="purple" style="font-family: Helvetica; font-size: medium; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class="WordSection1" style="page: WordSection1; "><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">Hi,<o:p></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">I have discovered another simple false positive report from the static analyzer that seems to be clearly wrong. I think it is related to not processing bit fields correctly.<o:p></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">I have attached the HTML report and copied the problematic function below (in case the attachment doesn’t work).<o:p></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">#pragma inline(Fpga_Xbus_Busy_Wait)<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">static void Fpga_Xbus_Busy_Wait(void)<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">{<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">#ifndef SOLUTION_ENGINE<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> /* Stores result of the XBUS busy request. */<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 rsp;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> </span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">#if DXL_DEBUG_ENABLE<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> /* Initialize the number of loops to 0. */<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UNSIGNED fpga_samples = 0;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">#endif<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> <o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> /* Make sure that the Xbus is idle. */<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> do {<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> rsp = PCI_Rd_Mem_Long(FPGA_PCI_MEM_ADDR+FPGA_STATUS_READ, 0);<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">#if DXL_DEBUG_ENABLE<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> fpga_samples++;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">#endif<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> } while(((fpga_status_t *) &rsp)->xbus_busy);<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> </span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">#if DXL_DEBUG_ENABLE<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> /* Determine if the longest FPGA XBUS wait has been exceeded. */<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> if(FPGA_longest < fpga_samples)<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> FPGA_longest = fpga_samples;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">#endif<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> </span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">#endif // ifndef SOLUTION ENGINE.<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">}<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">The analyzer reports the following error:<o:p></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">build\DXL\Intercom\src\init\fpga.c:119:13: warning: Branch condition evaluates to a garbage value<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> } while(((fpga_status_t *) &rsp)->xbus_busy);<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">The function reads from a PCI bus and assigns the value read to the 32 bit variable rsp inside the do loop. The loop condition takes the address of rsp and casts it to a structure pointer, then dereferences the pointer to access the field xbus_busy. The definition of the structure is copied below:<o:p></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">typedef struct<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">{<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 usb2_armed_status :1;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 usb1_armed_status :1;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 xbus_busy :1;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 :1;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 column :4;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 :1;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 keypad_configuration :2; <o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 cept_configuration :2; <o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 two_hundred_mhz_dsp :1; <o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 hwid :2;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; "> UINT32 version :16;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span style="font-family: Consolas; ">} fpga_status_t, fpga_configuration_t;<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">The analyzer seems to miss the fact that xbus_busy is a bit field in a single 32 bit variable, rather than a separate 32 variable in a structure. The error would make sense if the structure fields were independent 32 bit variables. Then xbus_busy would be a 32 bit field at offset 8 bytes past the start of the structure. This offset clearly doesn’t exist in the single 32 bit variable rsp.<o:p></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; ">HTH<o:p></o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span>--<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span>Dennis Cote<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span>Harding Instruments<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span>780-462-7100<o:p></o:p></span></div><div style="margin: 0cm 0cm 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><o:p> </o:p></div></div><span><report-030357.html></span>_______________________________________________<br>cfe-dev mailing list<br><a href="mailto:cfe-dev@cs.uiuc.edu" style="color: purple; text-decoration: underline; ">cfe-dev@cs.uiuc.edu</a><br><a href="http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev" style="color: purple; text-decoration: underline; ">http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev</a><br></div></blockquote></div><br></body></html>