JDevlieghere created this revision.
JDevlieghere added reviewers: labath, jasonmolenda.
Herald added a subscriber: abidh.
JDevlieghere updated this revision to Diff 250305.
JDevlieghere added a comment.
Share RLE-decoding logic.
The GDB replay server sanity-checks that every packet it receives matches what
it expects from the serialized packet log. This mechanism tripped for
`TestReproducerAttach.py` on Linux, because one of the packets (`jModulesInfo`)
uses run-length encoding. The replay server was comparing the expanded incoming
packet with the unexpanded packet in the log. As a result, it claimed to have
received an unexpected packet, which caused the test to fail.
This patch addresses that issue by expanding the run-length encoding before
comparing the packets.
https://reviews.llvm.org/D76163
Files:
lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationReplayServer.cpp
lldb/test/API/functionalities/reproducers/attach/TestReproducerAttach.py
Index: lldb/test/API/functionalities/reproducers/attach/TestReproducerAttach.py
===================================================================
--- lldb/test/API/functionalities/reproducers/attach/TestReproducerAttach.py
+++ lldb/test/API/functionalities/reproducers/attach/TestReproducerAttach.py
@@ -15,7 +15,6 @@
mydir = TestBase.compute_mydir(__file__)
NO_DEBUG_INFO_TESTCASE = True
- @skipIfLinux # Reproducer received unexpected packet.
@skipIfFreeBSD
@skipIfNetBSD
@skipIfWindows
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationReplayServer.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationReplayServer.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationReplayServer.cpp
@@ -131,22 +131,26 @@
GDBRemotePacket entry = m_packet_history.back();
m_packet_history.pop_back();
+ // Decode run-length encoding.
+ const std::string expanded_data =
+ GDBRemoteCommunication::ExpandRLE(entry.packet.data);
+
// We've handled the handshake implicitly before. Skip the packet and move
// on.
if (entry.packet.data == "+")
continue;
if (entry.type == GDBRemotePacket::ePacketTypeSend) {
- if (unexpected(entry.packet.data, packet.GetStringRef())) {
+ if (unexpected(expanded_data, packet.GetStringRef())) {
LLDB_LOG(log,
"GDBRemoteCommunicationReplayServer expected packet: '{0}'",
- entry.packet.data);
+ expanded_data);
LLDB_LOG(log, "GDBRemoteCommunicationReplayServer actual packet: '{0}'",
packet.GetStringRef());
#ifndef NDEBUG
// This behaves like a regular assert, but prints the expected and
// received packet before aborting.
- printf("Reproducer expected packet: '%s'\n", entry.packet.data.c_str());
+ printf("Reproducer expected packet: '%s'\n", expanded_data.c_str());
printf("Reproducer received packet: '%s'\n",
packet.GetStringRef().data());
llvm::report_fatal_error("Encountered unexpected packet during replay");
@@ -155,7 +159,7 @@
}
// Ignore QEnvironment packets as they're handled earlier.
- if (entry.packet.data.find("QEnvironment") == 1) {
+ if (expanded_data.find("QEnvironment") == 1) {
assert(m_packet_history.back().type ==
GDBRemotePacket::ePacketTypeRecv);
m_packet_history.pop_back();
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h
@@ -142,6 +142,9 @@
static llvm::Error ConnectLocally(GDBRemoteCommunication &client,
GDBRemoteCommunication &server);
+ /// Expand GDB run-length encoding.
+ static std::string ExpandRLE(std::string);
+
protected:
std::chrono::seconds m_packet_timeout;
uint32_t m_echo_number;
Index: lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -810,31 +810,9 @@
GDBRemotePacket::ePacketTypeRecv, total_length);
// Copy the packet from m_bytes to packet_str expanding the run-length
- // encoding in the process. Reserve enough byte for the most common case
- // (no RLE used)
- std ::string packet_str;
- packet_str.reserve(m_bytes.length());
- for (std::string::const_iterator c = m_bytes.begin() + content_start;
- c != m_bytes.begin() + content_end; ++c) {
- if (*c == '*') {
- // '*' indicates RLE. Next character will give us the repeat count
- // and previous character is what is to be repeated.
- char char_to_repeat = packet_str.back();
- // Number of time the previous character is repeated
- int repeat_count = *++c + 3 - ' ';
- // We have the char_to_repeat and repeat_count. Now push it in the
- // packet.
- for (int i = 0; i < repeat_count; ++i)
- packet_str.push_back(char_to_repeat);
- } else if (*c == 0x7d) {
- // 0x7d is the escape character. The next character is to be XOR'd
- // with 0x20.
- char escapee = *++c ^ 0x20;
- packet_str.push_back(escapee);
- } else {
- packet_str.push_back(*c);
- }
- }
+ // encoding in the process.
+ std ::string packet_str =
+ ExpandRLE(m_bytes.substr(content_start, content_end - content_start));
packet = StringExtractorGDBRemote(packet_str);
if (m_bytes[0] == '$' || m_bytes[0] == '%') {
@@ -1382,3 +1360,30 @@
break;
}
}
+
+std::string GDBRemoteCommunication::ExpandRLE(std::string packet) {
+ // Reserve enough byte for the most common case (no RLE used).
+ std::string decoded;
+ decoded.reserve(packet.size());
+ for (std::string::const_iterator c = packet.begin(); c != packet.end(); ++c) {
+ if (*c == '*') {
+ // '*' indicates RLE. Next character will give us the repeat count and
+ // previous character is what is to be repeated.
+ char char_to_repeat = decoded.back();
+ // Number of time the previous character is repeated.
+ int repeat_count = *++c + 3 - ' ';
+ // We have the char_to_repeat and repeat_count. Now push it in the
+ // packet.
+ for (int i = 0; i < repeat_count; ++i)
+ decoded.push_back(char_to_repeat);
+ } else if (*c == 0x7d) {
+ // 0x7d is the escape character. The next character is to be XOR'd with
+ // 0x20.
+ char escapee = *++c ^ 0x20;
+ decoded.push_back(escapee);
+ } else {
+ decoded.push_back(*c);
+ }
+ }
+ return decoded;
+}
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