llvm/llvm-project

clang crashes on x86_64-linux-gnu with Assertion `power <= maxExponent' failed

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#28,406 opened on Jun 7, 2016

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bugzillaclang:frontendconfirmedcrash-on-invalidgood first issue

Description
Bugzilla Link 28032
Version trunk
OS All
Reporter LLVM Bugzilla Contributor
CC @ekatz,@fhahn,@RKSimon,@slacka

Extended Description

The current clang trunk crashes when compiling the following test case on x86_64-linux-gnu in both 32-bit and 64-bit modes.

It seems to be a 3.9 regression.

$ clang-trunk -v
clang version 3.9.0 (trunk 271256)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/i686-linux-gnu/5.3.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/3.4.6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.4.7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.6.4
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.8.5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/4.9.3
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.3.0
Found candidate GCC installation: /usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0
Found candidate GCC installation: /usr/local/bin/../lib/gcc/x86_64-unknown-linux-gnu/5.3.0
Selected GCC installation: /usr/local/bin/../lib/gcc/x86_64-pc-linux-gnu/6.1.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64

$ clang-trunk abc.c -c
clang-3.9: /home/absozero/trunk/llvm/lib/Support/APFloat.cpp:469: unsigned int powerOf5(integerPart *, unsigned int): Assertion `power <= maxExponent' failed.
#0 0x00000000019c9b28 llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x19c9b28)
#1 0x00000000019c7d26 llvm::sys::RunSignalHandlers() (/home/absozero/trunk/root-clang/bin/clang-3.9+0x19c7d26)
#2 0x00000000019ca1fe SignalHandler(int) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x19ca1fe)
#3 0x00007fbcb3301340 __restore_rt (/lib/x86_64-linux-gnu/libpthread.so.0+0x10340)
#4 0x00007fbcb24b3cc9 gsignal /build/buildd/eglibc-2.19/signal/../nptl/sysdeps/unix/sysv/linux/raise.c:56:0
#5 0x00007fbcb24b70d8 abort /build/buildd/eglibc-2.19/stdlib/abort.c:91:0
#6 0x00007fbcb24acb86 __assert_fail_base /build/buildd/eglibc-2.19/assert/assert.c:92:0
#7 0x00007fbcb24acc32 (/lib/x86_64-linux-gnu/libc.so.6+0x2fc32)
#8 0x0000000001948a33 (/home/absozero/trunk/root-clang/bin/clang-3.9+0x1948a33)
#9 0x0000000001948e66 llvm::APFloat::convertFromDecimalString(llvm::StringRef, llvm::APFloat::roundingMode) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x1948e66)
#10 0x0000000003215329 clang::NumericLiteralParser::GetFloatValue(llvm::APFloat&) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x3215329)
#11 0x0000000002a22808 BuildFloatingLiteral(clang::Sema&, clang::NumericLiteralParser&, clang::QualType, clang::SourceLocation) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x2a22808)
#12 0x0000000002a21bb6 clang::Sema::ActOnNumericConstant(clang::Token const&, clang::Scope*) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x2a21bb6)
#13 0x000000000265941c clang::Parser::ParseCastExpression(bool, bool, bool&, clang::Parser::TypeCastState) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x265941c)
#14 0x0000000002655a6c clang::Parser::ParseAssignmentExpression(clang::Parser::TypeCastState) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x2655a6c)
#15 0x000000000263062e clang::Parser::ParseDeclarationAfterDeclaratorAndAttributes(clang::Declarator&, clang::Parser::ParsedTemplateInfo const&, clang::Parser::ForRangeInit*) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x263062e)
#16 0x000000000262e451 clang::Parser::ParseDeclGroup(clang::ParsingDeclSpec&, unsigned int, clang::SourceLocation*, clang::Parser::ForRangeInit*) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x262e451)
#17 0x0000000002616262 clang::Parser::ParseDeclOrFunctionDefInternal(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec&, clang::AccessSpecifier) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x2616262)
#18 0x0000000002615c40 clang::Parser::ParseDeclarationOrFunctionDefinition(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec*, clang::AccessSpecifier) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x2615c40)
#19 0x0000000002614d24 clang::Parser::ParseExternalDeclaration(clang::Parser::ParsedAttributesWithRange&, clang::ParsingDeclSpec*) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x2614d24)
#20 0x0000000002614306 clang::Parser::ParseTopLevelDecl(clang::OpaquePtr<clang::DeclGroupRef>&) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x2614306)
#21 0x00000000026100ba clang::ParseAST(clang::Sema&, bool, bool) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x26100ba)
#22 0x0000000001ef9995 clang::FrontendAction::Execute() (/home/absozero/trunk/root-clang/bin/clang-3.9+0x1ef9995)
#23 0x0000000001ec1a41 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x1ec1a41)
#24 0x0000000001f93161 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x1f93161)
#25 0x000000000075c66e cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/absozero/trunk/root-clang/bin/clang-3.9+0x75c66e)
#26 0x000000000075ab20 main (/home/absozero/trunk/root-clang/bin/clang-3.9+0x75ab20)
#27 0x00007fbcb249eec5 __libc_start_main /build/buildd/eglibc-2.19/csu/libc-start.c:321:0
#28 0x00000000007580a2 _start (/home/absozero/trunk/root-clang/bin/clang-3.9+0x7580a2)
Stack dump:
0.	Program arguments: /home/absozero/trunk/root-clang/bin/clang-3.9 -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -mrelax-all -disable-free -main-file-name abc.c -mrelocation-model static -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column-info -debugger-tuning=gdb -coverage-file /home/absozero/projects/reduction/crash/abc.c -resource-dir /home/absozero/trunk/root-clang/bin/../lib/clang/3.9.0 -internal-isystem /usr/local/include -internal-isystem /home/absozero/trunk/root-clang/bin/../lib/clang/3.9.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fdebug-compilation-dir /home/absozero/projects/reduction/crash -ferror-limit 19 -fmessage-length 172 -fobjc-runtime=gcc -fdiagnostics-show-option -fcolor-diagnostics -o abc.o -x c abc.c
1.	abc.c:1:15: current parser token '1.82259976594123730126420296680970990819952540784678167186049024351418584431669886840478035431291360259862367367360176555098349281631101608498675403779490450274191129058896583928461263190281677987831078128299170536447015989677676363429562039997708640550775926919152302738435771122464765292985913410713131103376617773042203403962987686984411316948595140667733210597864690600010838133614601613871681951542280276489775942764960612766058558174381456923146501775692637508015664228929367328342904167452656185259699435199165429391997316125073430122973318829343522821181735512119859732943017878403356723899138210986814640887564778026842288063392332395425873162546186801975636139070797668304819972220170105852674422401098888180221895434381162451705845464727526614177730212750823552425549507762484741018808753638726079896241463208233641468961241718926107442376223082667022657044926746945053999973304249789647043354111258394904631316614206681676861518285530333635550805084849345427276340804672339278791177264322833523245464353153129378096510959641978734303986620037096633539629329212395162630085725125582600936685277823883492820153083593049415051104450437620211914690606070787926358977364081411635544299722928735751692643879771301240039585999097767207595829950175191441110017783298397938554546884420461552538187244104722816024213635806139907491818083029479760454178844362711626647761487494632027538147971912063924809690969103877295273058627398067023490884558283804713066036286365630374146882657021080984305152976459971071596872478304966869803153760915112192273767083898623101906331345170408354325877269319107750447803297770519645747631196394042357976659226774333324024028170376571419266465026123884210852547563237372731787743310739247077115755551931534219571260621965209529206118711148614230326874252623232432768485954951338025914378049849860538923653349006471371371975851619548239568383911087481548770985671906958133943927799958876422544137402326929408872363515336911744925148845142650068227520261364354697002916289429272868432749597813293152504173604381153301045168945974496048759541471080100519101973888604170033075957748634771829115251095545428834602408676747944708548838154240391870140692461377047103665770055763116743840798104372065112827921945625030361510289100654183705651174880622260739758549192434399417410164472062845437778260804090757560281944655628120766454222846704757309223464545058305531743779508241780347081470374488718989636990233738212174195604234593588461272325314215528265459543623864312796269176427251818027542711345978562318056661295241015095829415854218885612968394742320564741129353791774349282275541494026428939134920627812463726111753054622717119310116356020391377016695730659609458715794206834400971798313683173521572022151606820588780251530071841853198634516520873759366510045598375024838080906130739822646856203519935194543445776352574523286837269888247054743973982471908128830717347432604265401234817912837829289728424665952102694142190409017939355538720903773940059325978870813594819158491785411281829232728432185130930121677446908186036638626917272725653250577033788275532848525020676860268503396244010460868170366183668422400245220420698887085348274712352039989322593091109423678562877840971664204374301183812473393474181569023692824311977350780165916130639182603434989926970020331865584136555767033892083012035521577557018520518779278646965154203692177035106027598152525747997287067958495583828773920163969005601017367414626907539916022639742121376325089842645593155408913831923616011893504143113588169809756975685615156809718301077041526572845529202418627301258888257023010355646157596158820107337643411098344495769079824062658034841113036159712976090652715172861118398396463438153644617763942735713912193155539153353006222951965776408842015246576140657437291217544606529750759900127860216624160777572354875625503811168240060144404381782532731747344361636381195322953833511355431708115960517850363668467732859378452319744244754189705176591797980699728768894888776273098873237375908148750504573178096251637132279732290029080034917390851159718996069867384057524634361867451078210323154806935160062513887899020538632350719578957221218762625988338233522900425764882381207240722674803484256371990031477603784632430434075343952218821448873158758760259077397922975757953735064291924684701700383120505009176657075834209273037908753324078050945056651597552104952664855941872449222161542832136880323939394014264995176092751280620673551723331208577960453876924923755340564701453016713590166028324696751231085985884240222167593347334526263303037916609526590361628275094514687712979547371657019216768348669940844962684915105995807144581550267466768607900288997226458836794359699020464423731084729515154927619118848472118259301156549275391180883502559594450767573982988933806622483582100752977021911865196145152803953417231772013838628271297216496382745313147623777787545601193971231801073102166081571418283792593282745084673717170570311045377504502284479416196840733756305173220061186402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clang-3.9: error: unable to execute command: Aborted (core dumped)
clang-3.9: error: clang frontend command failed due to signal (use -v to see invocation)
clang version 3.9.0 (trunk 271256)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
clang-3.9: note: diagnostic msg: PLEASE submit a bug report to http://llvm.org/bugs/ and include the crash backtrace, preprocessed source, and associated run script.
clang-3.9: note: diagnostic msg:
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-3.9: note: diagnostic msg: /tmp/abc-67ee29.c
clang-3.9: note: diagnostic msg: /tmp/abc-67ee29.sh
clang-3.9: note: diagnostic msg:

********************

$ cat abc.c

long double a=1.8225997659412373012642029668097099081995254078467816718604902435141858443166988684047803543129136025986236736736017655509834928163110160849867540377949045027419112905889658392846126319028167798783107812829917053644701598967767636342956203999770864055077592691915230273843577112246476529298591341071313110337661777304220340396298768698441131694859514066773321059786469060001083813361460161387168195154228027648977594276496061276605855817438145692314650177569263750801566422892936732834290416745265618525969943519916542939199731612507343012297331882934352282118173551211985973294301787840335672389913821098681464088756477802684228806339233239542587316254618680197563613907079766830481997222017010585267442240109888818022189543438116245170584546472752661417773021275082355242554950776248474101880875363872607989624146320823364146896124171892610744237622308266702265704492674694505399997330424978964704335411125839490463131661420668167686151828553033363555080508484934542727634080467233927879117726432283352324546435315312937809651095964197873430398662003709663353962932921239516263008572512558260093668527782388349282015308359304941505110445043762021191469060607078792635897736408141163554429972292873575169264387977130124003958599909776720759582995017519144111001778329839793855454688442046155253818724410472281602421363580613990749181808302947976045417884436271162664776148749463202753814797191206392480969096910387729527305862739806702349088455828380471306603628636563037414688265702108098430515297645997107159687247830496686980315376091511219227376708389862310190633134517040835432587726931910775044780329777051964574763119639404235797665922677433332402402817037657141926646502612388421085254756323737273178774331073924707711575555193153421957126062196520952920611871114861423032687425262323243276848595495133802591437804984986053892365334900647137137197585161954823956838391108748154877098567190695813394392779995887642254413740232692940887236351533691174492514884514265006822752026136435469700291628942927286843274959781329315250417360438115330104516894597449604875954147108010051910197388860417003307595774863477182911525109554542883460240867674794470854883815424039187014069246137704710366577005576311674384079810437206511282792194562503036151028910065418370565117488062226073975854919243439941741016447206284543777826080409075756028194465562812076645422284670475730922346454505830553174377950824178034708147037448871898963699023373821217419560423459358846127232531421552826545954362386431279626917642725181802754271134597856231805666129524101509582941585421888561296839474232056474112935379177434928227554149402642893913492062781246372611175305462271711931011635602039137701669573065960945871579420683440097179831368317352157202215160682058878025153007184185319863451652087375936651004559837502483808090613073982264685620351993519454344577635257452328683726988824705474397398247190812883071734743260426540123481791283782928972842466595210269414219040901793935553872090377394005932597887081359481915849178541128182923272843218513093012167744690818603663862691727272565325057703378827553284852502067686026850339624401046086817036618366842240024522042069888708534827471235203998932259309110942367856287784097166420437430118381247339347418156902369282431197735078016591613063918260343498992697002033186558413655576703389208301203552157755701852051877927864696515420369217703510602759815252574799728706795849558382877392016396900560101736741462690753991602263974212137632508984264559315540891383192361601189350414311358816980975697568561515680971830107704152657284552920241862730125888825702301035564615759615882010733764341109834449576907982406265803484111303615971297609065271517286111839839646343815364461776394273571391219315553915335300622295196577640884201524657614065743729121754460652975075990012786021662416077757235487562550381116824006014440438178253273174734436163638119532295383351135543170811596051785036366846773285937845231974424475418970517659179798069972876889488877627309887323737590814875050457317809625163713227973229002908003491739085115971899606986738405752463436186745107821032315480693516006251388789902053863235071957895722121876262598833823352290042576488238120724072267480348425637199003147760378463243043407534395221882144887315875876025907739792297575795373506429192468470170038312050500917665707583420927303790875332407805094505665159755210495266485594187244922216154283213688032393939401426499517609275128062067355172333120857796045387692492375534056470145301671359016602832469675123108598588424022216759334733452626330303791660952659036162827509451468771297954737165701921676834866994084496268491510599580714458155026746676860790028899722645883679435969902046442373108472951515492761911884847211825930115654927539118088350255959445076757398298893380662248358210075297702191186519614515280395341723177201383862827129721649638274531314762377778754560119397123180107310216608157141828379259328274508467371717057031104537750450228447941619684073375630517322006118640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Contributor guide

Tech stack
cpp
Domain
backend
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
5
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
familiarity with LLVM's APFloat libraryunderstanding of floating point representationexperience with debugger and compiler internals
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
5
Research direction
The crash occurs in APFloat.cpp at line 469 in powerOf5 due to an assertion 'power <= maxExponent' failed. The reproduction involves compiling a file with an extremely long floating point literal. The first step is to obtain the full reduced test case, then examine the conversion from decimal string to APFloat. The bug appears to be a regression in clang 3.9. Investigate the change in APFloat that introduced the issue, possibly around handling of very large exponents or the powerOf5 function's bounds. Check the LLVM bug tracker for related patches or discussions in the comments.