malaperle-ericsson updated this revision to Diff 90774.
malaperle-ericsson added a comment.
[clangd] Fix not being able to attach a debugger on macOS
Clangd is often waiting for input on getline as it awaits requests.
If the getline is interrupted, it causes the system call (read) to
fail and the EINTR error to be set. This can be seen when attaching
a debugger such as LLDB on macOS. On macOS (and possibly other
operating systems), this system call is not restarted after
interruption but on Linux it is restarted which is why attaching a
debugger does work correctly there.
The solution is to work around the non-restarting system call by
checking the errno for EINTR when the stream fails and try again.
This should be safe on all Unixish platforms.
See also http://bugs.llvm.org/show_bug.cgi?id=32149 for some background
discussion.
https://reviews.llvm.org/D30476
Files:
clangd/ClangDMain.cpp
Index: clangd/ClangDMain.cpp
===================================================================
--- clangd/ClangDMain.cpp
+++ clangd/ClangDMain.cpp
@@ -67,6 +67,12 @@
// by \r\n.
std::string Line;
std::getline(std::cin, Line);
+#ifdef LLVM_ON_UNIX
+ if (!std::cin.good() && errno == EINTR) {
+ std::cin.clear();
+ continue;
+ }
+#endif
// Skip empty lines.
llvm::StringRef LineRef(Line);
Index: clangd/ClangDMain.cpp
===================================================================
--- clangd/ClangDMain.cpp
+++ clangd/ClangDMain.cpp
@@ -67,6 +67,12 @@
// by \r\n.
std::string Line;
std::getline(std::cin, Line);
+#ifdef LLVM_ON_UNIX
+ if (!std::cin.good() && errno == EINTR) {
+ std::cin.clear();
+ continue;
+ }
+#endif
// Skip empty lines.
llvm::StringRef LineRef(Line);
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