[llvm] r282422 - [llvm-cov] Silence a warning from the MSVC runtime (NFC)
Vedant Kumar via llvm-commits
llvm-commits at lists.llvm.org
Mon Sep 26 10:57:13 PDT 2016
Author: vedantk
Date: Mon Sep 26 12:57:13 2016
New Revision: 282422
URL: http://llvm.org/viewvc/llvm-project?rev=282422&view=rev
Log:
[llvm-cov] Silence a warning from the MSVC runtime (NFC)
Rework getLongestCommonPrefixLen() so that it doesn't access string null
terminators. The old version with std::mismatch would do this:
|
v
Strings[0] = ['a', nil]
Strings[1] = ['a', 'a', nil]
^
|
This should silence a warning from the MSVC runtime (PR30515). As
before, I tested this out by preparing a coverage report for FileCheck.
Thanks to Yaron Keren for the report!
Modified:
llvm/trunk/tools/llvm-cov/CoverageReport.cpp
Modified: llvm/trunk/tools/llvm-cov/CoverageReport.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-cov/CoverageReport.cpp?rev=282422&r1=282421&r2=282422&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-cov/CoverageReport.cpp (original)
+++ llvm/trunk/tools/llvm-cov/CoverageReport.cpp Mon Sep 26 12:57:13 2016
@@ -123,10 +123,12 @@ raw_ostream::Colors determineCoveragePer
unsigned getLongestCommonPrefixLen(ArrayRef<std::string> Strings) {
unsigned LCP = Strings[0].size();
for (unsigned I = 1, E = Strings.size(); LCP > 0 && I < E; ++I) {
- auto Mismatch =
- std::mismatch(Strings[0].begin(), Strings[0].end(), Strings[I].begin())
- .first;
- LCP = std::min(LCP, (unsigned)std::distance(Strings[0].begin(), Mismatch));
+ unsigned Cursor;
+ StringRef S = Strings[I];
+ for (Cursor = 0; Cursor < LCP && Cursor < S.size(); ++Cursor)
+ if (Strings[0][Cursor] != S[Cursor])
+ break;
+ LCP = std::min(LCP, Cursor);
}
return LCP;
}
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