[llvm] 62af02e - [XRay] Sanitize DOT labels in graph output
Nathan James via llvm-commits
llvm-commits at lists.llvm.org
Mon Mar 9 05:06:06 PDT 2020
Author: Alex Cameron
Date: 2020-03-09T12:05:57Z
New Revision: 62af02e76fe808134b06b75c8108a98c079ac8bc
URL: https://github.com/llvm/llvm-project/commit/62af02e76fe808134b06b75c8108a98c079ac8bc
DIFF: https://github.com/llvm/llvm-project/commit/62af02e76fe808134b06b75c8108a98c079ac8bc.diff
LOG: [XRay] Sanitize DOT labels in graph output
Summary:
Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=39701
This patch is to convert certain characters to their XML escape sequences when generating labels for a DOT graph.
I had trouble reproducing the exact issue described on the tracker. I ran `llvm-xray graph` on a log from a test program that included function templates but wasn't able to get the `dot` tool to complain about the `<` and `>` characters. The documentation also suggests that the escape sequences should only be necessary when using HTML string labels which XRay doesn't use (`label=<...>` as opposed to `label="..."`). Perhaps newer versions of Graphviz silently handle this in the case of quoted-string labels.
In any case, the generated labels still look correct after this patch and should also fix the reporter's issue.
I was a bit unsure how to add a test for this since the existing tests seem to only care about `func-id` rather than giving an actual name. If you could give me a hint on the best way to go about this, that'd be much appreciated!
Reviewers: dberris
Reviewed By: dberris
Subscribers: lebedev.ri, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69461
Added:
Modified:
llvm/tools/llvm-xray/xray-graph.cpp
Removed:
################################################################################
diff --git a/llvm/tools/llvm-xray/xray-graph.cpp b/llvm/tools/llvm-xray/xray-graph.cpp
index f836f9ba54fc..522609b938f2 100644
--- a/llvm/tools/llvm-xray/xray-graph.cpp
+++ b/llvm/tools/llvm-xray/xray-graph.cpp
@@ -163,6 +163,30 @@ static void updateStat(GraphRenderer::TimeStat &S, int64_t L) {
S.Sum += L;
}
+// Labels in a DOT graph must be legal XML strings so it's necessary to escape
+// certain characters.
+static std::string escapeString(StringRef Label) {
+ std::string Str;
+ Str.reserve(Label.size());
+ for (const auto C : Label) {
+ switch (C) {
+ case '&':
+ Str.append("&");
+ break;
+ case '<':
+ Str.append("<");
+ break;
+ case '>':
+ Str.append(">");
+ break;
+ default:
+ Str.push_back(C);
+ break;
+ }
+ }
+ return Str;
+}
+
// Evaluates an XRay record and performs accounting on it.
//
// If the record is an ENTER record it pushes the FuncID and TSC onto a
@@ -398,8 +422,9 @@ void GraphRenderer::exportGraphAsDOT(raw_ostream &OS, StatType ET, StatType EC,
if (V.first == 0)
continue;
OS << "F" << V.first << " [label=\"" << (VT != StatType::NONE ? "{" : "")
- << (VA.SymbolName.size() > 40 ? VA.SymbolName.substr(0, 40) + "..."
- : VA.SymbolName);
+ << escapeString(VA.SymbolName.size() > 40
+ ? VA.SymbolName.substr(0, 40) + "..."
+ : VA.SymbolName);
if (VT != StatType::NONE)
OS << "|" << VA.S.getString(VT) << "}\"";
else
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