<div dir="ltr">Shooting from the hip, it sounds like your StringRef is dangling (pointing to deallocated memory, etc). I'd suggest you try Valgrind to possibly get a better sense of what's going on.</div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, May 4, 2016 at 6:18 AM, 詹石岩 via cfe-dev <span dir="ltr"><<a href="mailto:cfe-dev@lists.llvm.org" target="_blank">cfe-dev@lists.llvm.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">I wrote a clang tool based on libtooling.
<br>This tool will insert some code into the source file through Rewriter.
<br><br>I encounted SIGBUS when insert a sentence after a SourceLocation.
<br>I debugged using CLion and found this SIGBUS happend here:
<br><br>Rewriter.cpp, Line 257 @Rewriter::InsertText(SourceLocation Loc, String Ref Str, bool InsertAfter, bool IndentNewLine)
<br><br>the code writes:
<br>while(isWhitespaceExceptNL(MB[i]) //the<b> MB[i]</b> will cause SIGBUS sometimes.
<br><br>The MB is a instance of StringRef
<br><br>I encounted this problem only for the main.c and utils.c from graph500-2.1.4, in the mpi folder.
<br><br>when processing main.c, the problem happens when trying to insert a '\n' after the for statement in line 45:
<br>for(i=0;i<n;++i) tmp+=x[i];
<br>-------------------^-----//try to insert here
<br><br>can anyone tells me how to check the problem?
<br><br>I used gcc4.8.4, Linux Mint 17.3, kernel version:3.13.0-24, core i7 4710M<br><br>here is my code:<br>(if I delete the code before <pre style="background-color:#ffffff;color:#000000;font-family:'DejaVu Sans Mono';font-size:9.0pt"><span style="color:#000080;font-weight:bold">if</span>(!isa<<span style="color:#008080">CompoundStmt</span>>(stmt))</pre> then the problem disappears)<br><br><pre style="background-color:#ffffff;color:#000000;font-family:'DejaVu Sans Mono';font-size:9.0pt"><span style="color:#1f542e;font-weight:bold">bool </span><span style="color:#008080">StmtHandler</span>::InsertText(<span style="color:#008080">Stmt </span>*stmt, <span style="color:#371f80">string </span>toInsert) {<br> <span style="color:#808080;font-style:italic">//get rewriter from buffer<br></span><span style="color:#808080;font-style:italic"> </span><span style="color:#008080">SourceLocation </span>slc = stmt->getLocStart();<br> <span style="color:#000080;font-weight:bold">unsigned int </span>fsl = <span style="color:#660e7a">TheContext</span>.getFullLoc(slc).getSpellingColumnNumber();<br><br> <span style="color:#371f80">string </span>filename = <span style="color:#660e7a">TheContext</span>.getSourceManager().getFilename(slc).str();<br> <span style="color:#371f80">FileIdMap</span>::<span style="color:#371f80">iterator </span>index = <span style="color:#660e7a">fileMap</span>.find(filename);<br> <span style="color:#008080">FileID </span>id = <span style="color:#660e7a">TheRewriter</span>.getSourceMgr().getFileID(slc);<br> <span style="color:#000080;font-weight:bold">if</span>(index <span style="color:#008080">== </span><span style="color:#660e7a">fileMap</span>.end()){<br> <span style="color:#660e7a">fileMap</span><span style="color:#008080">[</span>filename<span style="color:#008080">] </span>= id;<br> <span style="color:#808080;font-style:italic">//we need to judge whether the file was instrumented already<br></span><span style="color:#808080;font-style:italic"> </span><span style="color:#000080;font-weight:bold">const </span><span style="color:#008080">RewriteBuffer </span>&buffer = <span style="color:#660e7a">TheRewriter</span>.getEditBuffer(id);<br> <span style="color:#371f80">string </span>content(buffer.begin(), buffer.end());<br> <span style="color:#371f80">size_t </span>pos = content.find(<span style="color:#008000;font-weight:bold">'</span><span style="color:#000080;font-weight:bold">\n</span><span style="color:#008000;font-weight:bold">'</span>, <span style="color:#0000ff">0</span>);<br> <span style="color:#371f80">string </span>start = content.substr(<span style="color:#0000ff">0</span>, pos + <span style="color:#0000ff">1</span>);<br> <span style="color:#371f80">string </span>comp = <span style="color:#008000;font-weight:bold">"//instrumented "</span><span style="color:#008080">+</span><span style="color:#660e7a">namespace_origin</span><span style="color:#008080">+</span><span style="color:#008000;font-weight:bold">"</span><span style="color:#000080;font-weight:bold">\n</span><span style="color:#008000;font-weight:bold">"</span>;<br> <span style="color:#808080;font-style:italic">//if we can not write the file, we regard it as instrumented<br></span><span style="color:#808080;font-style:italic"> </span><span style="color:#008080">std</span>::<span style="color:#008080">error_code </span>OutErrorInfo;<br> <span style="color:#008080">std</span>::<span style="color:#008080">error_code </span>ok;<br> <span style="color:#008080">llvm</span>::<span style="color:#008080">raw_fd_ostream </span>tmpFile(filename, OutErrorInfo, <span style="color:#008080">llvm</span>::<span style="color:#008080">sys</span>::<span style="color:#008080">fs</span>::<span style="color:#660e7a;font-weight:bold;font-style:italic">F_RW</span>);<br> <span style="color:#000080;font-weight:bold">if</span>(OutErrorInfo <span style="color:#008080">!= </span>ok){<br> <span style="color:#660e7a">fileInstrumented</span><span style="color:#008080">[</span>id<span style="color:#008080">] </span>= <span style="color:#1f542e;font-weight:bold">true</span>;<br> <span style="color:#000080;font-weight:bold">return </span><span style="color:#1f542e;font-weight:bold">false</span>;<br> }<br> <span style="color:#808080;font-style:italic">//see if this file was ever instrumented<br></span><span style="color:#808080;font-style:italic"> </span><span style="color:#000080;font-weight:bold">if</span>(start <span style="color:#008080">!= </span>comp){<br> <span style="color:#660e7a">fileInstrumented</span><span style="color:#008080">[</span>id<span style="color:#008080">] </span>= <span style="color:#1f542e;font-weight:bold">false</span>;<br> <span style="color:#660e7a">TheRewriter</span>.InsertText(<span style="color:#660e7a">TheRewriter</span>.getSourceMgr().getLocForStartOfFile(id), comp,<span style="color:#1f542e;font-weight:bold">false</span>);<br> }<span style="color:#000080;font-weight:bold">else</span>{<br> <span style="color:#660e7a">fileInstrumented</span><span style="color:#008080">[</span>id<span style="color:#008080">] </span>= <span style="color:#1f542e;font-weight:bold">true</span>;<br> <span style="color:#008080">llvm</span>::errs()<span style="color:#008080"><<</span><span style="color:#008000;font-weight:bold">"file "</span><span style="color:#008080"><<</span>filename<span style="color:#008080"><<</span><span style="color:#008000;font-weight:bold">" was ignored.</span><span style="color:#000080;font-weight:bold">\n</span><span style="color:#008000;font-weight:bold">"</span>;<br> <span style="color:#000080;font-weight:bold">return </span><span style="color:#1f542e;font-weight:bold">false</span>;<br> }<br><br> }<span style="color:#000080;font-weight:bold">else</span>{<br> <span style="color:#000080;font-weight:bold">if</span>(<span style="color:#660e7a">fileInstrumented</span><span style="color:#008080">[</span>id<span style="color:#008080">]</span>)<br> <span style="color:#000080;font-weight:bold">return </span><span style="color:#1f542e;font-weight:bold">false</span>;<br> }<br><br> <span style="color:#000080;font-weight:bold">if</span>(!isa<<span style="color:#008080">CompoundStmt</span>>(stmt)){<br> <span style="color:#008080">SourceLocation </span>ST = stmt->getLocStart();<br><span style="color:#808080;font-style:italic"></span><span style="color:#808080;font-style:italic"><br></span><span style="color:#808080;font-style:italic"> </span><span style="color:#660e7a">TheRewriter</span>.InsertText(ST, <span style="color:#008000;font-weight:bold">"{</span><span style="color:#000080;font-weight:bold">\n</span><span style="color:#008000;font-weight:bold">"</span>, <span style="color:#1f542e;font-weight:bold">true</span>, <span style="color:#1f542e;font-weight:bold">true</span>);<br> <span style="color:#660e7a">TheRewriter</span>.InsertText(ST, toInsert <span style="color:#008080">+ </span><span style="color:#008000;font-weight:bold">"</span><span style="color:#000080;font-weight:bold">\n</span><span style="color:#008000;font-weight:bold">"</span>, <span style="color:#1f542e;font-weight:bold">true</span>, <span style="color:#1f542e;font-weight:bold">true</span>);<span style="color:#808080;font-style:italic"><br></span><span style="color:#808080;font-style:italic"> </span><span style="color:#008080">SourceLocation </span><span style="background-color:#ffe4ff">END</span> = stmt->getLocEnd();<span style="color:#808080;font-style:italic"><br> </span><span style="color:#000080;font-weight:bold">int </span>offset = <span style="color:#008080">Lexer</span>::MeasureTokenLength(<span style="background-color:#e4e4ff">END</span>,<br> <span style="color:#660e7a">TheRewriter</span>.getSourceMgr(),<br> <span style="color:#660e7a">TheRewriter</span>.getLangOpts()) + <span style="color:#0000ff">1</span>;<br><br> <span style="color:#008080">SourceLocation </span>END1 = <span style="background-color:#e4e4ff">END</span>.getLocWithOffset(offset);<br> <span style="color:#660e7a">TheRewriter</span>.InsertText(END1, <span style="color:#008000;font-weight:bold">"</span><span style="color:#000080;font-weight:bold">\n</span><span style="color:#008000;font-weight:bold">}"</span>, <span style="color:#1f542e;font-weight:bold">true</span>, <span style="color:#1f542e;font-weight:bold">true</span>);<br> }<br> <span style="color:#000080;font-weight:bold">else</span>{<br> <span style="color:#008080">CompoundStmt </span>*compstmt = cast<<span style="color:#008080">CompoundStmt</span>>(stmt);<br> <span style="color:#008080">SourceLocation </span>compLoc = compstmt->getLocStart();<br> <span style="color:#660e7a">TheRewriter</span>.InsertText(compLoc.getLocWithOffset(<span style="color:#0000ff">1</span>),<span style="color:#008000;font-weight:bold">"</span><span style="color:#000080;font-weight:bold">\n</span><span style="color:#008000;font-weight:bold">"</span><span style="color:#008080">+</span>toInsert<span style="color:#008080">+</span><span style="color:#008000;font-weight:bold">"</span><span style="color:#000080;font-weight:bold">\n</span><span style="color:#008000;font-weight:bold">"</span>, <span style="color:#1f542e;font-weight:bold">true</span>, <span style="color:#1f542e;font-weight:bold">true</span>);<br> }<br> <span style="color:#000080;font-weight:bold">return </span><span style="color:#1f542e;font-weight:bold">true</span>;<br>}</pre><br>_______________________________________________<br>
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<br></blockquote></div><br></div>