wallace updated this revision to Diff 299236.
wallace marked 3 inline comments as done.
wallace added a comment.
Addressed almost all changes.
What's left to discuss:
- I tried to use obj2yaml, but it creates files much larger than the binaries,
so in terms of space, I'd rather keep the binaries. Besides, I removed ld.so,
and the binaries that are left are tiny. I imagine that the binaries that will
be committed in the future will also be tiny ones depicting specific edge cases.
- Showing the disassembly of the instructions, requested by Greg, is not yet
done.
- I'm representing now all decoding errors as instructions, which in fact
simplifies the API a good deal. However, I'm still not happy with the API,
right now we have
class Trace {
void TraverseInstructions(Thread, callback, ...);
int GetInstructionsCount(Thread...);
}
Right now these methods are not doing anything (or returning 0) if the provided
Thread is not traced by the Trace instance. Which is kind of what
ThreadList::GetThreadAtIndex does, as well as many other APIs. To keep
consistency with most of LLDB core APIs, we could leave the code as it is,
which simplifies a lot the API.
class Trace {
TracedThreadSP GetTraceForThread(Thread ...);
}
class TracedThread {
void TraverseInstructions(callback, ...);
int GetInstructionsCount()
}
This creates a level of indirection that forces the caller to check if the
returned TracedTrace is a valid pointer or not. If the pointer is invalid, the
caller can show an error message or fail silenty, otherwise,
TraverseInstructions and GetInstructionsCount will perform valid operations.
This might become useful to avoid errors in complex scenarios as the API grows.
But then, how often will someone invoke these methods with the wrong thread?
The first form of the API looks simpler without that level of indirection,
which is cool.
What do you guys think?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D89283/new/
https://reviews.llvm.org/D89283
Files:
lldb/include/lldb/Target/ProcessTrace.h
lldb/include/lldb/Target/Trace.h
lldb/source/Plugins/Trace/intel-pt/CMakeLists.txt
lldb/source/Plugins/Trace/intel-pt/DecodedThread.cpp
lldb/source/Plugins/Trace/intel-pt/DecodedThread.h
lldb/source/Plugins/Trace/intel-pt/IntelPTDecoder.cpp
lldb/source/Plugins/Trace/intel-pt/IntelPTDecoder.h
lldb/source/Plugins/Trace/intel-pt/TraceIntelPT.cpp
lldb/source/Plugins/Trace/intel-pt/TraceIntelPT.h
lldb/source/Target/ProcessTrace.cpp
lldb/source/Target/Trace.cpp
lldb/source/Target/TraceSessionFileParser.cpp
lldb/test/API/commands/trace/TestTraceDumpInstructions.py
lldb/test/API/commands/trace/intelpt-trace-multi-file/a.out
lldb/test/API/commands/trace/intelpt-trace-multi-file/bar.cpp
lldb/test/API/commands/trace/intelpt-trace-multi-file/bar.h
lldb/test/API/commands/trace/intelpt-trace-multi-file/foo.cpp
lldb/test/API/commands/trace/intelpt-trace-multi-file/foo.h
lldb/test/API/commands/trace/intelpt-trace-multi-file/libbar.so
lldb/test/API/commands/trace/intelpt-trace-multi-file/libfoo.so
lldb/test/API/commands/trace/intelpt-trace-multi-file/main.cpp
lldb/test/API/commands/trace/intelpt-trace-multi-file/multi-file-no-ld.json
lldb/test/API/commands/trace/intelpt-trace-multi-file/multi-file.trace
lldb/test/API/commands/trace/intelpt-trace/trace_bad_image.json
lldb/test/API/commands/trace/intelpt-trace/trace_wrong_cpu.json
Index: lldb/test/API/commands/trace/intelpt-trace/trace_wrong_cpu.json
===================================================================
--- /dev/null
+++ lldb/test/API/commands/trace/intelpt-trace/trace_wrong_cpu.json
@@ -0,0 +1,31 @@
+{
+ "trace": {
+ "type": "intel-pt",
+ "pt_cpu": {
+ "vendor": "intel",
+ "family": 2123123,
+ "model": 12123123,
+ "stepping": 1231231
+ }
+ },
+ "processes": [
+ {
+ "pid": 1234,
+ "triple": "x86_64-*-linux",
+ "threads": [
+ {
+ "tid": 3842849,
+ "traceFile": "3842849.trace"
+ }
+ ],
+ "modules": [
+ {
+ "file": "a.out",
+ "systemPath": "a.out",
+ "loadAddress": "0x0000000000400000",
+ "uuid": "6AA9A4E2-6F28-2F33-377D-59FECE874C71-5B41261A"
+ }
+ ]
+ }
+ ]
+}
Index: lldb/test/API/commands/trace/intelpt-trace/trace_bad_image.json
===================================================================
--- /dev/null
+++ lldb/test/API/commands/trace/intelpt-trace/trace_bad_image.json
@@ -0,0 +1,31 @@
+{
+ "trace": {
+ "type": "intel-pt",
+ "pt_cpu": {
+ "vendor": "intel",
+ "family": 6,
+ "model": 79,
+ "stepping": 1
+ }
+ },
+ "processes": [
+ {
+ "pid": 1234,
+ "triple": "x86_64-*-linux",
+ "threads": [
+ {
+ "tid": 3842849,
+ "traceFile": "3842849.trace"
+ }
+ ],
+ "modules": [
+ {
+ "file": "a.out",
+ "systemPath": "a.out",
+ "loadAddress": "0x0000000000FFFFF0",
+ "uuid": "6AA9A4E2-6F28-2F33-377D-59FECE874C71-5B41261A"
+ }
+ ]
+ }
+ ]
+}
Index: lldb/test/API/commands/trace/intelpt-trace-multi-file/multi-file-no-ld.json
===================================================================
--- /dev/null
+++ lldb/test/API/commands/trace/intelpt-trace-multi-file/multi-file-no-ld.json
@@ -0,0 +1,43 @@
+{
+ "trace": {
+ "type": "intel-pt",
+ "pt_cpu": {
+ "vendor": "intel",
+ "family": 6,
+ "model": 79,
+ "stepping": 1
+ }
+ },
+ "processes": [
+ {
+ "pid": 815455,
+ "triple": "x86_64-*-linux",
+ "threads": [
+ {
+ "tid": 815455,
+ "traceFile": "multi-file.trace"
+ }
+ ],
+ "modules": [
+ {
+ "file": "a.out",
+ "systemPath": "a.out",
+ "loadAddress": "0x0000000000400000",
+ "uuid": "729BF711-43CB-0017-AADF-83304FEA5EC4-D46B45DD"
+ },
+ {
+ "file": "libfoo.so",
+ "systemPath": "libfoo.so",
+ "loadAddress": "0x00007ffff7bd9000",
+ "uuid": "B30FFEDA-8BB2-3D08-4580-C5937ED11E2B-21BE778C"
+ },
+ {
+ "file": "libbar.so",
+ "systemPath": "libbar.so",
+ "loadAddress": "0x00007ffff79d7000",
+ "uuid": "6633B038-EA73-D1A6-FF9A-7D0C0EDF733D-95FEA2CC"
+ }
+ ]
+ }
+ ]
+}
Index: lldb/test/API/commands/trace/intelpt-trace-multi-file/main.cpp
===================================================================
--- /dev/null
+++ lldb/test/API/commands/trace/intelpt-trace-multi-file/main.cpp
@@ -0,0 +1,7 @@
+#include "foo.h"
+
+int main() {
+ int res = foo();
+ res++;
+ return res;
+}
Index: lldb/test/API/commands/trace/intelpt-trace-multi-file/foo.h
===================================================================
--- /dev/null
+++ lldb/test/API/commands/trace/intelpt-trace-multi-file/foo.h
@@ -0,0 +1 @@
+int foo();
Index: lldb/test/API/commands/trace/intelpt-trace-multi-file/foo.cpp
===================================================================
--- /dev/null
+++ lldb/test/API/commands/trace/intelpt-trace-multi-file/foo.cpp
@@ -0,0 +1,7 @@
+#include "bar.h"
+
+int foo() {
+ int y = bar();
+ y++;
+ return y;
+}
Index: lldb/test/API/commands/trace/intelpt-trace-multi-file/bar.h
===================================================================
--- /dev/null
+++ lldb/test/API/commands/trace/intelpt-trace-multi-file/bar.h
@@ -0,0 +1 @@
+int bar();
Index: lldb/test/API/commands/trace/intelpt-trace-multi-file/bar.cpp
===================================================================
--- /dev/null
+++ lldb/test/API/commands/trace/intelpt-trace-multi-file/bar.cpp
@@ -0,0 +1,5 @@
+int bar() {
+ int x = 1;
+ x++;
+ return x;
+}
Index: lldb/test/API/commands/trace/TestTraceDumpInstructions.py
===================================================================
--- lldb/test/API/commands/trace/TestTraceDumpInstructions.py
+++ lldb/test/API/commands/trace/TestTraceDumpInstructions.py
@@ -12,7 +12,7 @@
TestBase.setUp(self)
if 'intel-pt' not in configuration.enabled_plugins:
self.skipTest("The intel-pt test plugin is not enabled")
-
+
def testErrorMessages(self):
# We first check the output when there are no targets
self.expect("thread trace dump instructions",
@@ -39,18 +39,41 @@
substrs=["intel-pt"])
self.expect("thread trace dump instructions",
- substrs=['thread #1: tid = 3842849, total instructions = 1000',
- 'would print 20 instructions from position 0'])
+ substrs=['''thread #1: tid = 3842849, total instructions = 21
+ [ 0] 0x40052d
+ [ 1] 0x400529
+ [ 2] 0x400525
+ [ 3] 0x400521
+ [ 4] 0x40052d
+ [ 5] 0x400529
+ [ 6] 0x400525
+ [ 7] 0x400521
+ [ 8] 0x40052d
+ [ 9] 0x400529
+ [10] 0x400525
+ [11] 0x400521
+ [12] 0x40052d
+ [13] 0x400529
+ [14] 0x400525
+ [15] 0x400521
+ [16] 0x40052d
+ [17] 0x400529
+ [18] 0x40051f
+ [19] 0x400518'''])
# We check if we can pass count and offset
self.expect("thread trace dump instructions --count 5 --start-position 10",
- substrs=['thread #1: tid = 3842849, total instructions = 1000',
- 'would print 5 instructions from position 10'])
+ substrs=['''thread #1: tid = 3842849, total instructions = 21
+ [10] 0x400525
+ [11] 0x400521
+ [12] 0x40052d
+ [13] 0x400529
+ [14] 0x400525'''])
# We check if we can access the thread by index id
self.expect("thread trace dump instructions 1",
- substrs=['thread #1: tid = 3842849, total instructions = 1000',
- 'would print 20 instructions from position 0'])
+ substrs=['''thread #1: tid = 3842849, total instructions = 21
+ [ 0] 0x40052d'''])
# We check that we get an error when using an invalid thread index id
self.expect("thread trace dump instructions 10", error=True,
@@ -61,32 +84,103 @@
self.expect("trace load -v " + os.path.join(self.getSourceDir(), "intelpt-trace", "trace_2threads.json"))
# We print the instructions of two threads simultaneously
- self.expect("thread trace dump instructions 1 2",
- substrs=['''thread #1: tid = 3842849, total instructions = 1000
- would print 20 instructions from position 0
-thread #2: tid = 3842850, total instructions = 1000
- would print 20 instructions from position 0'''])
+ self.expect("thread trace dump instructions 1 2 --count 2",
+ substrs=['''thread #1: tid = 3842849, total instructions = 21
+ [0] 0x40052d
+ [1] 0x400529
+thread #2: tid = 3842850, total instructions = 21
+ [0] 0x40052d
+ [1] 0x400529'''])
# We use custom --count and --start-position, saving the command to history for later
ci = self.dbg.GetCommandInterpreter()
result = lldb.SBCommandReturnObject()
- ci.HandleCommand("thread trace dump instructions 1 2 --count 12 --start-position 5", result, True)
- self.assertIn('''thread #1: tid = 3842849, total instructions = 1000
- would print 12 instructions from position 5
-thread #2: tid = 3842850, total instructions = 1000
- would print 12 instructions from position 5''', result.GetOutput())
+ ci.HandleCommand("thread trace dump instructions 1 2 --count 4 --start-position 5", result, True)
+ self.assertIn('''thread #1: tid = 3842849, total instructions = 21
+ [5] 0x400529
+ [6] 0x400525
+ [7] 0x400521
+ [8] 0x40052d
+thread #2: tid = 3842850, total instructions = 21
+ [5] 0x400529
+ [6] 0x400525
+ [7] 0x400521
+ [8] 0x40052d''', result.GetOutput())
# We use a repeat command and ensure the previous count is used and the start-position has moved to the next position
+
result = lldb.SBCommandReturnObject()
ci.HandleCommand("", result)
- self.assertIn('''thread #1: tid = 3842849, total instructions = 1000
- would print 12 instructions from position 17
-thread #2: tid = 3842850, total instructions = 1000
- would print 12 instructions from position 17''', result.GetOutput())
+ self.assertIn('''thread #1: tid = 3842849, total instructions = 21
+ [ 9] 0x400529
+ [10] 0x400525
+ [11] 0x400521
+ [12] 0x40052d
+thread #2: tid = 3842850, total instructions = 21
+ [ 9] 0x400529
+ [10] 0x400525
+ [11] 0x400521
+ [12] 0x40052d''', result.GetOutput())
+ result = lldb.SBCommandReturnObject()
ci.HandleCommand("", result)
- self.assertIn('''thread #1: tid = 3842849, total instructions = 1000
- would print 12 instructions from position 29
-thread #2: tid = 3842850, total instructions = 1000
- would print 12 instructions from position 29''', result.GetOutput())
+ self.assertIn('''thread #1: tid = 3842849, total instructions = 21
+ [13] 0x400529
+ [14] 0x400525
+ [15] 0x400521
+ [16] 0x40052d
+thread #2: tid = 3842850, total instructions = 21
+ [13] 0x400529
+ [14] 0x400525
+ [15] 0x400521
+ [16] 0x40052d''', result.GetOutput())
+
+ def testInvalidBounds(self):
+ self.expect("trace load -v " + os.path.join(self.getSourceDir(), "intelpt-trace", "trace.json"))
+
+ # The output should be truncated if asking for too many instructions
+ self.expect("thread trace dump instructions --count 20 --start-position 20",
+ substrs=['''thread #1: tid = 3842849, total instructions = 21
+ [20] 0x400511'''])
+
+ # Should print no instructions if the start-position is out of bounds
+ self.expect("thread trace dump instructions --start-position 23",
+ endstr='thread #1: tid = 3842849, total instructions = 21\n')
+
+ # Should fail with negative bounds
+ self.expect("thread trace dump instructions --start-position -1", error=True)
+ self.expect("thread trace dump instructions --count -1", error=True)
+
+ def testWrongImage(self):
+ self.expect("trace load " + os.path.join(self.getSourceDir(), "intelpt-trace", "trace_bad_image.json"))
+ self.expect("thread trace dump instructions",
+ substrs=['''thread #1: tid = 3842849, total instructions = 2
+ [0] error: no memory mapped at this address 0x400518
+ [1] error: no memory mapped at this address 0x400511'''])
+
+ def testWrongCPU(self):
+ self.expect("trace load " + os.path.join(self.getSourceDir(), "intelpt-trace", "trace_wrong_cpu.json"))
+ self.expect("thread trace dump instructions",
+ substrs=['''thread #1: tid = 3842849, total instructions = 1
+ [0] error: unknown cpu'''])
+
+ def testMultiFileTraceWithMissingModule(self):
+ self.expect("trace load " + os.path.join(self.getSourceDir(), "intelpt-trace-multi-file", "multi-file-no-ld.json"))
+
+ # The trace will be composed of the first and last instructions of main.cpp, with an unmapped region in between
+ # corresponding to the dynamic linker, which is missing in the json file. Because of this error, the decoder moves
+ # to the next synchronization point, skipping the instructions of bar.cpp and foo.cpp.
+ self.expect("thread trace dump instructions",
+ substrs=['''thread #1: tid = 815455, total instructions = 11
+ [ 0] 0x40065f
+ [ 1] 0x40065a
+ [ 2] 0x400657
+ [ 3] 0x400654
+ [ 4] error: no memory mapped at this address 0x7ffff7df1950
+ [ 5] 0x400516
+ [ 6] 0x400510
+ [ 7] 0x40054b
+ [ 8] 0x400546
+ [ 9] 0x400540
+ [10] 0x40064f'''])
Index: lldb/source/Target/TraceSessionFileParser.cpp
===================================================================
--- lldb/source/Target/TraceSessionFileParser.cpp
+++ lldb/source/Target/TraceSessionFileParser.cpp
@@ -37,7 +37,6 @@
ModuleSpec module_spec;
module_spec.GetFileSpec() = local_file_spec;
module_spec.GetPlatformFileSpec() = system_file_spec;
- module_spec.SetObjectOffset(module.load_address.value);
if (module.uuid.hasValue())
module_spec.GetUUID().SetFromStringRef(*module.uuid);
@@ -45,7 +44,14 @@
Status error;
ModuleSP module_sp =
target_sp->GetOrCreateModule(module_spec, /*notify*/ false, &error);
- return error.ToError();
+
+ if (error.Fail())
+ return error.ToError();
+
+ bool load_addr_changed = false;
+ module_sp->SetLoadAddress(*target_sp, module.load_address.value, false,
+ load_addr_changed);
+ return llvm::Error::success();
}
Error TraceSessionFileParser::CreateJSONError(json::Path::Root &root,
Index: lldb/source/Target/Trace.cpp
===================================================================
--- lldb/source/Target/Trace.cpp
+++ lldb/source/Target/Trace.cpp
@@ -8,8 +8,6 @@
#include "lldb/Target/Trace.h"
-#include <sstream>
-
#include "llvm/Support/Format.h"
#include "lldb/Core/PluginManager.h"
@@ -79,10 +77,34 @@
return createInvalidPlugInError(name);
}
+static int GetNumberOfDigits(size_t num) {
+ return num == 0 ? 1 : static_cast<int>(log10(num)) + 1;
+}
+
void Trace::DumpTraceInstructions(Thread &thread, Stream &s, size_t count,
- size_t start_position) const {
- s.Printf("thread #%u: tid = %" PRIu64 ", total instructions = 1000\n",
- thread.GetIndexID(), thread.GetID());
- s.Printf(" would print %zu instructions from position %zu\n", count,
- start_position);
+ size_t start_position) {
+ s.Printf("thread #%u: tid = %" PRIu64 "", thread.GetIndexID(),
+ thread.GetID());
+ if (count == 0)
+ return;
+
+ size_t instructions_count = GetInstructionCount(thread);
+ s.Printf(", total instructions = %zu\n", instructions_count);
+
+ // Used for formatting the instruction indices
+ int digits_count =
+ GetNumberOfDigits(std::min(instructions_count, start_position + count));
+
+ TraverseInstructions(
+ thread, start_position, TraceDirection::Backwards,
+ [&](size_t index, Expected<lldb::addr_t> load_address) -> bool {
+ s.Printf(" [%*zu]", digits_count, index);
+ if (load_address)
+ s.Printf(" 0x%" PRIx64, *load_address);
+ else
+ s.Printf(" %s", toString(load_address.takeError()).c_str());
+ s.Printf("\n");
+
+ return --count > 0;
+ });
}
Index: lldb/source/Target/ProcessTrace.cpp
===================================================================
--- lldb/source/Target/ProcessTrace.cpp
+++ lldb/source/Target/ProcessTrace.cpp
@@ -12,6 +12,8 @@
#include "lldb/Core/Module.h"
#include "lldb/Core/PluginManager.h"
+#include "lldb/Core/Section.h"
+#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/Target.h"
using namespace lldb;
@@ -121,5 +123,9 @@
size_t ProcessTrace::DoReadMemory(addr_t addr, void *buf, size_t size,
Status &error) {
- return 0;
+ Address resolved_address;
+ GetTarget().GetSectionLoadList().ResolveLoadAddress(addr, resolved_address);
+
+ return GetTarget().ReadMemoryFromFileCache(resolved_address, buf, size,
+ error);
}
Index: lldb/source/Plugins/Trace/intel-pt/TraceIntelPT.h
===================================================================
--- lldb/source/Plugins/Trace/intel-pt/TraceIntelPT.h
+++ lldb/source/Plugins/Trace/intel-pt/TraceIntelPT.h
@@ -9,12 +9,8 @@
#ifndef LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_TRACEINTELPT_H
#define LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_TRACEINTELPT_H
-#include "intel-pt.h"
-#include "llvm/ADT/Optional.h"
-
+#include "IntelPTDecoder.h"
#include "TraceIntelPTSessionFileParser.h"
-#include "lldb/Target/Trace.h"
-#include "lldb/lldb-private.h"
namespace lldb_private {
namespace trace_intel_pt {
@@ -59,6 +55,13 @@
llvm::StringRef GetSchema() override;
+ void TraverseInstructions(
+ const Thread &thread, size_t position, TraceDirection direction,
+ std::function<bool(size_t index, llvm::Expected<lldb::addr_t> load_addr)>
+ callback) override;
+
+ size_t GetInstructionCount(const Thread &thread) override;
+
private:
friend class TraceIntelPTSessionFileParser;
@@ -68,8 +71,20 @@
TraceIntelPT(const pt_cpu &pt_cpu,
const std::vector<std::shared_ptr<ThreadTrace>> &traced_threads);
+ /// Decode the trace of the given thread that, i.e. recontruct the traced
+ /// instructions. That trace must be managed by this class.
+ ///
+ /// \param[in] thread
+ /// If \a thread is a \a ThreadTrace, then its internal trace file will be
+ /// decoded. Live threads are not currently supported.
+ ///
+ /// \return
+ /// A \a DecodedThread instance if decoding was successful, or a \b nullptr
+ /// if the thread's trace is not managed by this class.
+ const DecodedThread *Decode(const Thread &thread);
+
pt_cpu m_pt_cpu;
- std::map<std::pair<lldb::pid_t, lldb::tid_t>, std::shared_ptr<ThreadTrace>>
+ std::map<std::pair<lldb::pid_t, lldb::tid_t>, ThreadTraceDecoder>
m_trace_threads;
};
Index: lldb/source/Plugins/Trace/intel-pt/TraceIntelPT.cpp
===================================================================
--- lldb/source/Plugins/Trace/intel-pt/TraceIntelPT.cpp
+++ lldb/source/Plugins/Trace/intel-pt/TraceIntelPT.cpp
@@ -64,5 +64,40 @@
: m_pt_cpu(pt_cpu) {
for (const std::shared_ptr<ThreadTrace> &thread : traced_threads)
m_trace_threads.emplace(
- std::make_pair(thread->GetProcess()->GetID(), thread->GetID()), thread);
+ std::piecewise_construct,
+ std::forward_as_tuple(thread->GetProcess()->GetID(), thread->GetID()),
+ std::forward_as_tuple(thread, pt_cpu));
+}
+
+const DecodedThread *TraceIntelPT::Decode(const Thread &thread) {
+ auto it = m_trace_threads.find(
+ std::make_pair(thread.GetProcess()->GetID(), thread.GetID()));
+ if (it == m_trace_threads.end())
+ return nullptr;
+ return &it->second.Decode();
+}
+
+void TraceIntelPT::TraverseInstructions(
+ const Thread &thread, size_t position, TraceDirection direction,
+ std::function<bool(size_t index, Expected<lldb::addr_t> load_addr)>
+ callback) {
+ const DecodedThread *decoded_thread = Decode(thread);
+ if (!decoded_thread) {
+ return;
+ }
+
+ ArrayRef<IntelPTInstruction> instructions = decoded_thread->GetInstructions();
+
+ ssize_t delta = direction == TraceDirection::Forwards ? -1 : 1;
+ for (ssize_t i = position; i < (ssize_t)instructions.size() && i >= 0;
+ i += delta)
+ if (!callback(i, instructions[i].GetLoadAddress()))
+ break;
+}
+
+size_t TraceIntelPT::GetInstructionCount(const Thread &thread) {
+ if (const DecodedThread *decoded_thread = Decode(thread))
+ return decoded_thread->GetInstructions().size();
+ else
+ return 0;
}
Index: lldb/source/Plugins/Trace/intel-pt/IntelPTDecoder.h
===================================================================
--- /dev/null
+++ lldb/source/Plugins/Trace/intel-pt/IntelPTDecoder.h
@@ -0,0 +1,76 @@
+//===-- IntelPTDecoder.h --======--------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_DECODER_H
+#define LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_DECODER_H
+
+#include "intel-pt.h"
+
+#include "DecodedThread.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Utility/FileSpec.h"
+
+namespace lldb_private {
+namespace trace_intel_pt {
+
+class IntelPTDecoder {
+public:
+ /// \param[in] process
+ /// The process associated with the traces to decode.
+ ///
+ /// \param[in] pt_cpu
+ /// The libipt \a pt_cpu information of the CPU where the traces were
+ /// recorded.
+ IntelPTDecoder(Process &process, const pt_cpu &pt_cpu)
+ : m_process(process), m_pt_cpu(pt_cpu) {}
+
+ /// Decode a single-thread trace file.
+ ///
+ /// \param[in] trace_file
+ /// The binary trace file obtained from tracing a thread.
+ ///
+ /// \return
+ /// A \a DecodedTrace instance, or an error if decoding failed.
+ DecodedThread DecodeSingleThreadTraceFile(const FileSpec &trace_file);
+
+private:
+ Process &m_process;
+ pt_cpu m_pt_cpu;
+};
+
+/// \a lldb_private::ThreadTrace decoder that stores the output from decoding,
+/// avoiding recomputations, as decoding is expensive.
+class ThreadTraceDecoder {
+public:
+ /// \param[in] trace_thread
+ /// The thread whose trace file will be decoded.
+ ///
+ /// \param[in] pt_cpu
+ /// The libipt cpu used when recording the trace.
+ ThreadTraceDecoder(const std::shared_ptr<ThreadTrace> &trace_thread,
+ const pt_cpu &pt_cpu)
+ : m_trace_thread(trace_thread), m_pt_cpu(pt_cpu), m_decoded_thread() {}
+
+ /// Decode the thread and store the result internally.
+ ///
+ /// \return
+ /// A \a DecodedThread instance.
+ const DecodedThread &Decode();
+
+private:
+ ThreadTraceDecoder(const ThreadTraceDecoder &other) = delete;
+
+ std::shared_ptr<ThreadTrace> m_trace_thread;
+ pt_cpu m_pt_cpu;
+ llvm::Optional<DecodedThread> m_decoded_thread;
+};
+
+} // namespace trace_intel_pt
+} // namespace lldb_private
+
+#endif // LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_DECODER_H
Index: lldb/source/Plugins/Trace/intel-pt/IntelPTDecoder.cpp
===================================================================
--- /dev/null
+++ lldb/source/Plugins/Trace/intel-pt/IntelPTDecoder.cpp
@@ -0,0 +1,217 @@
+//===-- IntelPTDecoder.cpp --------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "IntelPTDecoder.h"
+
+#include "llvm/Support/MemoryBuffer.h"
+
+#include "lldb/Core/Module.h"
+#include "lldb/Core/Section.h"
+#include "lldb/Target/Target.h"
+#include "lldb/Target/ThreadTrace.h"
+
+using namespace lldb;
+using namespace lldb_private;
+using namespace lldb_private::trace_intel_pt;
+using namespace llvm;
+
+namespace {
+
+/// Move the decoder forward to the next synchronization point (i.e. next PSB
+/// packet).
+///
+/// Once the decoder is at that sync. point, it can start decoding instructions.
+///
+/// \return
+/// A negative number with the libipt error if we couldn't synchronize.
+/// Otherwise, a positive number with the synchronization status will be
+/// returned.
+int FindNextSynchronizationPoint(pt_insn_decoder &decoder) {
+ // Try to sync the decoder. If it fails, then get
+ // the decoder_offset and try to sync again from
+ // the next synchronization point. If the
+ // new_decoder_offset is same as decoder_offset
+ // then we can't move to the next synchronization
+ // point. Otherwise, keep resyncing until either
+ // end of trace stream (eos) is reached or
+ // pt_insn_sync_forward() passes.
+ int errcode = pt_insn_sync_forward(&decoder);
+
+ if (errcode != -pte_eos && errcode < 0) {
+ uint64_t decoder_offset = 0;
+ int errcode_off = pt_insn_get_offset(&decoder, &decoder_offset);
+ if (errcode_off >= 0) { // we could get the offset
+ while (true) {
+ errcode = pt_insn_sync_forward(&decoder);
+ if (errcode >= 0 || errcode == -pte_eos)
+ break;
+
+ uint64_t new_decoder_offset = 0;
+ errcode_off = pt_insn_get_offset(&decoder, &new_decoder_offset);
+ if (errcode_off < 0)
+ break; // We can't further synchronize.
+ else if (new_decoder_offset <= decoder_offset) {
+ // We tried resyncing the decoder and
+ // decoder didn't make any progress because
+ // the offset didn't change. We will not
+ // make any progress further. Hence,
+ // stopping in this situation.
+ break;
+ }
+ // We'll try again starting from a new offset.
+ decoder_offset = new_decoder_offset;
+ }
+ }
+ }
+
+ return errcode;
+}
+
+/// Before querying instructions, we need to query the events associated that
+/// instruction e.g. timing events like ptev_tick, or paging events like
+/// ptev_paging.
+///
+/// \return
+/// 0 if there were no errors processing the events, or a negative libipt
+/// error code in case of errors.
+int ProcessPTEvents(pt_insn_decoder &decoder, int errcode) {
+ while (errcode & pts_event_pending) {
+ pt_event event;
+ errcode = pt_insn_event(&decoder, &event, sizeof(event));
+ if (errcode < 0)
+ return errcode;
+ }
+ return 0;
+};
+
+/// Decode all the instructions from a configured decoder.
+/// The decoding flow is based on
+/// https://github.com/intel/libipt/blob/master/doc/howto_libipt.md#the-instruction-flow-decode-loop
+/// but with some relaxation to allow for gaps in the trace.
+///
+/// Error codes returned by libipt while decoding are:
+/// - negative: actual errors
+/// - positive or zero: not an error, but a list of bits signaling the status of
+/// the decoder
+///
+/// \param[in] decoder
+/// A configured libipt \a pt_insn_decoder.
+///
+/// \return
+/// The decoded instructions.
+std::vector<IntelPTInstruction> DecodeInstructions(pt_insn_decoder &decoder) {
+ std::vector<IntelPTInstruction> instructions;
+
+ while (true) {
+ int errcode = FindNextSynchronizationPoint(decoder);
+ if (errcode == -pte_eos)
+ break;
+
+ if (errcode < 0) {
+ instructions.emplace_back(errcode);
+ break;
+ }
+
+ // We have synchronized, so we can start decoding
+ // instructions and events.
+ while (true) {
+ errcode = ProcessPTEvents(decoder, errcode);
+ if (errcode < 0) {
+ instructions.emplace_back(errcode);
+ break;
+ }
+ pt_insn insn;
+
+ errcode = pt_insn_next(&decoder, &insn, sizeof(insn));
+ if (errcode == -pte_eos)
+ break;
+
+ if (errcode < 0) {
+ instructions.emplace_back(insn, errcode);
+ break;
+ }
+
+ instructions.emplace_back(insn);
+ }
+ }
+
+ return instructions;
+}
+
+/// Callback used by libipt for reading the process memory.
+///
+/// More information can be found in
+/// https://github.com/intel/libipt/blob/master/doc/man/pt_image_set_callback.3.md
+int ReadProcessMemory(uint8_t *buffer, size_t size,
+ const pt_asid * /* unused */, uint64_t pc,
+ void *context) {
+ Process *process = static_cast<Process *>(context);
+
+ Status error;
+ int bytes_read = process->ReadMemory(pc, buffer, size, error);
+ if (error.Fail())
+ return -pte_nomap;
+ return bytes_read;
+}
+
+std::vector<IntelPTInstruction>
+CreateDecoderAndDecode(Process &process, const pt_cpu &pt_cpu,
+ const FileSpec &trace_file) {
+ ErrorOr<std::unique_ptr<MemoryBuffer>> trace_or_error =
+ MemoryBuffer::getFile(trace_file.GetPath());
+ if (std::error_code err = trace_or_error.getError())
+ return {IntelPTInstruction(errorCodeToError(err))};
+
+ MemoryBuffer &trace = **trace_or_error;
+
+ pt_config config;
+ pt_config_init(&config);
+ config.cpu = pt_cpu;
+
+ if (int errcode = pt_cpu_errata(&config.errata, &config.cpu))
+ return {IntelPTInstruction(errcode)};
+
+ // The libipt library does not modify the trace buffer, hence the following
+ // cast is safe.
+ config.begin =
+ reinterpret_cast<uint8_t *>(const_cast<char *>(trace.getBufferStart()));
+ config.end =
+ reinterpret_cast<uint8_t *>(const_cast<char *>(trace.getBufferEnd()));
+
+ pt_insn_decoder *decoder = pt_insn_alloc_decoder(&config);
+ if (!decoder)
+ return {IntelPTInstruction(-pte_nomem)};
+
+ pt_image *image = pt_insn_get_image(decoder);
+ assert(pt_image_set_callback(image, ReadProcessMemory, &process) == 0);
+
+ std::vector<IntelPTInstruction> instructions = DecodeInstructions(*decoder);
+ // We'll need the instructions in reverse order chronologically, so we
+ // reverse them now
+ std::reverse(instructions.begin(), instructions.end());
+
+ pt_insn_free_decoder(decoder);
+ return instructions;
+}
+
+} // namespace
+
+DecodedThread
+IntelPTDecoder::DecodeSingleThreadTraceFile(const FileSpec &trace_file) {
+ return DecodedThread(CreateDecoderAndDecode(m_process, m_pt_cpu, trace_file));
+}
+
+const DecodedThread &ThreadTraceDecoder::Decode() {
+ if (!m_decoded_thread.hasValue()) {
+ IntelPTDecoder decoder(*m_trace_thread->GetProcess(), m_pt_cpu);
+ m_decoded_thread =
+ decoder.DecodeSingleThreadTraceFile(m_trace_thread->GetTraceFile());
+ }
+
+ return *m_decoded_thread;
+}
Index: lldb/source/Plugins/Trace/intel-pt/DecodedThread.h
===================================================================
--- /dev/null
+++ lldb/source/Plugins/Trace/intel-pt/DecodedThread.h
@@ -0,0 +1,93 @@
+//===-- DecodedThread.h -----------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_DECODEDTHREAD_H
+#define LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_DECODEDTHREAD_H
+
+#include <vector>
+
+#include "llvm/Support/Error.h"
+
+#include "lldb/Target/Trace.h"
+
+#include "intel-pt.h"
+
+namespace lldb_private {
+namespace trace_intel_pt {
+
+/// \class IntelPTInstruction
+/// An instruction obtained from decoding a trace. It is either an actual
+/// instruction or an error indicating a gap in the trace.
+///
+/// Gaps in the trace can come in a few flavors:
+/// - tracing gaps (e.g. tracing was paused and then resumed)
+/// - tracing errors (e.g. buffer overflow)
+/// - decoding errors (e.g. some memory region couldn't be decoded)
+/// As mentioned, any gap is represented as an error in this class.
+class IntelPTInstruction {
+public:
+ IntelPTInstruction() = delete;
+
+ IntelPTInstruction(const pt_insn &pt_insn, int libipt_error_code = 0)
+ : m_pt_insn(pt_insn), m_libipt_error_code(libipt_error_code),
+ m_custom_error() {}
+
+ IntelPTInstruction(int libipt_error_code)
+ : m_pt_insn(), m_libipt_error_code(libipt_error_code), m_custom_error() {}
+
+ IntelPTInstruction(llvm::Error custom_error)
+ : m_pt_insn(), m_libipt_error_code(0),
+ m_custom_error(llvm::toString(std::move(custom_error))) {}
+
+ /// Check if this object represents an error (i.e. a gap).
+ ///
+ /// \return
+ /// Whether this object represents an error.
+ bool IsError() const;
+
+ /// Get the instruction pointer if this is not an error.
+ ///
+ /// \return
+ /// The instruction pointer address.
+ llvm::Expected<lldb::addr_t> GetLoadAddress() const;
+
+ /// Return a descriptive error message if this is an error.
+ ///
+ /// \return
+ /// The error message.
+ std::string GetErrorMessage() const;
+
+private:
+ pt_insn m_pt_insn;
+ int m_libipt_error_code;
+ std::string m_custom_error;
+};
+
+/// \class DecodedThread
+/// Class holding the instructions and function call hierarchy obtained from
+/// decoding a trace.
+class DecodedThread {
+public:
+ DecodedThread(std::vector<IntelPTInstruction> &&instructions)
+ : m_instructions(std::move(instructions)) {}
+
+ /// Get the instructions from the decoded trace. Some of them might indicate
+ /// errors (i.e. gaps) in the trace.
+ ///
+ /// \return
+ /// The instructions of the trace.
+ llvm::ArrayRef<IntelPTInstruction> GetInstructions() const;
+
+private:
+ std::vector<IntelPTInstruction> m_instructions;
+};
+
+} // namespace trace_intel_pt
+} // namespace lldb_private
+
+#endif // LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_DECODEDTHREAD_H
Index: lldb/source/Plugins/Trace/intel-pt/DecodedThread.cpp
===================================================================
--- /dev/null
+++ lldb/source/Plugins/Trace/intel-pt/DecodedThread.cpp
@@ -0,0 +1,47 @@
+//===-- DecodedThread.cpp -------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "DecodedThread.h"
+
+#include <sstream>
+
+#include "lldb/Utility/StreamString.h"
+
+using namespace lldb_private;
+using namespace lldb_private::trace_intel_pt;
+using namespace llvm;
+
+bool IntelPTInstruction::IsError() const {
+ return m_libipt_error_code < 0 || !m_custom_error.empty();
+}
+
+Expected<lldb::addr_t> IntelPTInstruction::GetLoadAddress() const {
+ if (IsError())
+ return createStringError(std::errc::invalid_argument,
+ GetErrorMessage().data());
+ return m_pt_insn.ip;
+}
+
+std::string IntelPTInstruction::GetErrorMessage() const {
+ StreamString message;
+ message.Printf("error: ");
+
+ if (!m_custom_error.empty())
+ message << m_custom_error;
+ else {
+ message << pt_errstr(pt_errcode(m_libipt_error_code));
+ if (m_libipt_error_code == -pte_nomap)
+ message.Printf(" 0x%" PRIx64, m_pt_insn.ip);
+ }
+
+ return message.GetData();
+}
+
+ArrayRef<IntelPTInstruction> DecodedThread::GetInstructions() const {
+ return makeArrayRef(m_instructions);
+}
Index: lldb/source/Plugins/Trace/intel-pt/CMakeLists.txt
===================================================================
--- lldb/source/Plugins/Trace/intel-pt/CMakeLists.txt
+++ lldb/source/Plugins/Trace/intel-pt/CMakeLists.txt
@@ -10,6 +10,8 @@
find_library(LIBIPT_LIBRARY ipt PATHS ${LIBIPT_LIBRARY_PATH} REQUIRED)
add_lldb_library(lldbPluginTraceIntelPT PLUGIN
+ DecodedThread.cpp
+ IntelPTDecoder.cpp
TraceIntelPT.cpp
TraceIntelPTSessionFileParser.cpp
Index: lldb/include/lldb/Target/Trace.h
===================================================================
--- lldb/include/lldb/Target/Trace.h
+++ lldb/include/lldb/Target/Trace.h
@@ -35,6 +35,11 @@
class Trace : public PluginInterface,
public std::enable_shared_from_this<Trace> {
public:
+ enum class TraceDirection {
+ Forwards = 0,
+ Backwards,
+ };
+
/// Dump the trace data that this plug-in has access to.
///
/// This function will dump all of the trace data for all threads in a user
@@ -117,7 +122,49 @@
/// \param[in] start_position
/// The position of the first instruction to print.
void DumpTraceInstructions(Thread &thread, Stream &s, size_t count,
- size_t start_position) const;
+ size_t start_position);
+
+ /// Run the provided callback on the instructions of the trace of the given
+ /// thread.
+ ///
+ /// The instructions will be traversed starting at the \a from position
+ /// sequentially until the callback returns \b false, in which case no more
+ /// instructions are inspected.
+ ///
+ /// The purpose of this method is to allow inspecting traced instructions
+ /// without exposing the internal representation of how they are stored on
+ /// memory.
+ ///
+ /// \param[in] thread
+ /// The thread whose trace will be traversed.
+ ///
+ /// \param[in] position
+ /// The instruction position to start iterating on.
+ ///
+ /// \param[in] direction
+ /// If \b TraceDirection::Forwards, then then instructions will be
+ /// traversed forwards chronologically, i.e. with decrementing indices. If
+ /// \b TraceDirection::Backwards, the traversal is done backwards
+ /// chronologically, i.e. with incrementing indices.
+ ///
+ /// \param[in] callback
+ /// The callback to execute on each instruction. If it returns \b true for
+ /// the \a i-th instruction, then the instruction with index \a i + 1 will
+ /// be inspected. If it returns \b false, no more instructions will be
+ /// inspected.
+ virtual void TraverseInstructions(
+ const Thread &thread, size_t position, TraceDirection direction,
+ std::function<bool(size_t index, llvm::Expected<lldb::addr_t> load_addr)>
+ callback) = 0;
+
+ /// Get the number of available instructions in the trace of the given thread.
+ ///
+ /// \param[in] thread
+ /// The thread whose trace will be inspected.
+ ///
+ /// \return
+ /// The total number of instructions in the trace.
+ virtual size_t GetInstructionCount(const Thread &thread) = 0;
};
} // namespace lldb_private
Index: lldb/include/lldb/Target/ProcessTrace.h
===================================================================
--- lldb/include/lldb/Target/ProcessTrace.h
+++ lldb/include/lldb/Target/ProcessTrace.h
@@ -9,6 +9,7 @@
#ifndef LLDB_TARGET_PROCESSTRACE_H
#define LLDB_TARGET_PROCESSTRACE_H
+#include "lldb/Target/MemoryRegionInfo.h"
#include "lldb/Target/Process.h"
#include "lldb/Utility/ConstString.h"
#include "lldb/Utility/Status.h"
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