[flang-commits] [PATCH] D121124: [flang] Avoid crash case in provenance mapping
Peter Klausler via Phabricator via flang-commits
flang-commits at lists.llvm.org
Mon Mar 7 08:15:48 PST 2022
klausler created this revision.
klausler added a reviewer: mleair.
klausler added a project: Flang.
Herald added a subscriber: jdoerfert.
Herald added a project: All.
klausler requested review of this revision.
When a contiguous range of a cooked character stream is being
mapped to a range of source provenance, the code was assuming
that the "end()" position of the input range -- being the character
immediately after the range -- would also follow the range's
source provenance. This isn't always the case.
Modify the code to work with the true last character of the
input range (at end()-1) and to also cope with cases when that
last position truly maps to an earlier provenance, which can happen
when the prescanner has inserted a space into the cooked character
stream.
https://reviews.llvm.org/D121124
Files:
flang/lib/Parser/provenance.cpp
Index: flang/lib/Parser/provenance.cpp
===================================================================
--- flang/lib/Parser/provenance.cpp
+++ flang/lib/Parser/provenance.cpp
@@ -435,11 +435,15 @@
return std::nullopt;
}
ProvenanceRange first{provenanceMap_.Map(cookedRange.begin() - &data_[0])};
- if (cookedRange.size() <= first.size()) {
+ if (cookedRange.size() <= first.size()) { // always true when empty
return first.Prefix(cookedRange.size());
}
- ProvenanceRange last{provenanceMap_.Map(cookedRange.end() - &data_[0])};
- return {ProvenanceRange{first.start(), last.start() - first.start()}};
+ ProvenanceRange last{provenanceMap_.Map(cookedRange.end() - 1 - &data_[0])};
+ if (first.start() <= last.start()) {
+ return {ProvenanceRange{first.start(), last.start() - first.start() + 1}};
+ } else {
+ return std::nullopt;
+ }
}
std::optional<CharBlock> CookedSource::GetCharBlock(
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