[trace][intel pt] Add a nice parser for the trace size

[wallace]

Summary

Thanks to [e-mail] for coming up with these changes.

This diff adds support for passing units in the trace size inputs. For example,
it's now possible to specify 64KB as the trace size, instead of the
problematic 65536. This makes the user experience a bit friendlier.

As an example, I was able to trace a program with the following command

process trace start -s 64Kb

and then I saw this printed in the trace information

thread trace dump info                                                   

thread #1: tid = 469643
  Total number of trace items: 179982

  Memory usage:
    Raw trace size: 64 KiB

[wallace]

format

[jj10306]

lldb/source/Plugins/Trace/intel-pt/CommandObjectTraceStartIntelPT.cpp

174

nit

175–181

nit: this may be overkill but consider using constants here

lldb/source/Plugins/Trace/intel-pt/CommandObjectTraceStartIntelPT.h

 
 protected:
   bool DoExecute(Args &command, CommandReturnObject &result) override;
 
   TraceIntelPT &m_trace;
   CommandOptions m_options;
 };
 
+namespace ParsingUtils {
+/// Convert an integral size expression like 12KiB or 4MB into bytes. The units
+/// are taken loosely to help users input sizes into LLDB, e.g. KiB and KB are
+/// considered the same (2^20 bytes) for simplicity.
+///
+/// \param[in] size_expression
+///     String expression which is an integral number plus a unit that can be
+///     lower or upper case. Supported units: K, KB and KiB for 2^10 bytes; M,
+///     MB and MiB for 2^20 bytes; and B for bytes. A single integral number is
+///     considered bytes.
+/// \return
+///   The converted number of bytes or \a llvm::None if the expression is
+///   invalid.
+llvm::Optional<uint64_t>
+ParseUserFriendlySizeExpression(llvm::StringRef size_expression);
+} // namespace ParsingUtils
+
 } // namespace trace_intel_pt
 } // namespace lldb_private
 
 #endif // LLDB_SOURCE_PLUGINS_TRACE_INTEL_PT_COMMANDOBJECTTRACESTARTINTELPT_H

lldb/source/Plugins/Trace/intel-pt/CommandObjectTraceStartIntelPT.cpp

 Status CommandObjectThreadTraceStartIntelPT::CommandOptions::SetOptionValue(
     uint32_t option_idx, llvm::StringRef option_arg,
     ExecutionContext *execution_context) {
   Status error;
   const int short_option = m_getopt_table[option_idx].val;
 
   switch (short_option) {
   case 's': {
-    int64_t ipt_trace_size;
-    if (option_arg.empty() || option_arg.getAsInteger(0, ipt_trace_size) ||
-        ipt_trace_size < 0)
-      error.SetErrorStringWithFormat("invalid integer value for option '%s'",
-                                     option_arg.str().c_str());
+    if (Optional<uint64_t> bytes =
+            ParsingUtils::ParseUserFriendlySizeExpression(option_arg))
+      m_ipt_trace_size = *bytes;
     else
-      m_ipt_trace_size = ipt_trace_size;
+      error.SetErrorStringWithFormat("invalid bytes expression for '%s'",
+                                     option_arg.str().c_str());
     break;
   }
   case 't': {
     m_enable_tsc = true;
     break;
   }
   case 'p': {
     int64_t psb_period;

 Status CommandObjectProcessTraceStartIntelPT::CommandOptions::SetOptionValue(
     uint32_t option_idx, llvm::StringRef option_arg,
     ExecutionContext *execution_context) {
   Status error;
   const int short_option = m_getopt_table[option_idx].val;
 
   switch (short_option) {
   case 's': {
-    int64_t ipt_trace_size;
-    if (option_arg.empty() || option_arg.getAsInteger(0, ipt_trace_size) ||
-        ipt_trace_size < 0)
-      error.SetErrorStringWithFormat("invalid integer value for option '%s'",
-                                     option_arg.str().c_str());
+    if (Optional<uint64_t> bytes =
+            ParsingUtils::ParseUserFriendlySizeExpression(option_arg))
+      m_ipt_trace_size = *bytes;
     else
-      m_ipt_trace_size = ipt_trace_size;
+      error.SetErrorStringWithFormat("invalid bytes expression for '%s'",
+                                     option_arg.str().c_str());
     break;
   }
   case 'l': {
-    int64_t process_buffer_size_limit;
-    if (option_arg.empty() ||
-        option_arg.getAsInteger(0, process_buffer_size_limit) ||
-        process_buffer_size_limit < 0)
-      error.SetErrorStringWithFormat("invalid integer value for option '%s'",
-                                     option_arg.str().c_str());
+    if (Optional<uint64_t> bytes =
+            ParsingUtils::ParseUserFriendlySizeExpression(option_arg))
+      m_process_buffer_size_limit = *bytes;
     else
-      m_process_buffer_size_limit = process_buffer_size_limit;
+      error.SetErrorStringWithFormat("invalid bytes expression for '%s'",
+                                     option_arg.str().c_str());
     break;
   }
   case 't': {
     m_enable_tsc = true;
     break;
   }
   case 'c': {
     m_per_cpu_tracing = true;
if (Error err = m_trace.Start(m_options.m_ipt_trace_size,
                                 m_options.m_enable_tsc, m_options.m_psb_period,
                                 m_options.m_per_cpu_tracing))
     result.SetError(Status(std::move(err)));
   else
     result.SetStatus(eReturnStatusSuccessFinishResult);
 
   return result.Succeeded();
 }
+
+Optional<uint64_t>
+ParsingUtils::ParseUserFriendlySizeExpression(llvm::StringRef size_expression) {
+  if (size_expression.empty()) {
+    return llvm::None;
+  }
+
+  std::map<std::string, uint64_t> multipliers = {{"mib", 1024 * 1024},
+                                                 {"mb", 1024 * 1024},
+                                                 {"m", 1024 * 1024},
+                                                 {"kib", 1024},
+                                                 {"kb", 1024},
+                                                 {"k", 1024},
+                                                 {"b", 1},
+                                                 {"", 1}};
+
+  const auto non_digit_index = size_expression.find_first_not_of("0123456789");
+  if (non_digit_index == 0) { // expression starts from from non-digit char.
+    return llvm::None;
+  }
+
+  const llvm::StringRef number_part =
+      non_digit_index == llvm::StringRef::npos
+          ? size_expression
+          : size_expression.substr(0, non_digit_index);
+  uint64_t parsed_number;
+  if (number_part.getAsInteger(10, parsed_number)) {
+    return llvm::None;
+  }
+
+  if (non_digit_index != llvm::StringRef::npos) { // if expression has units.
+    const auto multiplier = size_expression.substr(non_digit_index).lower();
+
+    if (!multipliers.count(multiplier)) {
+      return llvm::None;
+    }
+
+    return parsed_number * multipliers.at(multiplier);
+  } else {
+    return parsed_number;
+  }
+}

lldb/source/Plugins/Trace/intel-pt/TraceIntelPT.cpp

 Error TraceIntelPT::Start(llvm::ArrayRef<lldb::tid_t> tids,
                           StructuredData::ObjectSP configuration) {
   uint64_t ipt_trace_size = kDefaultIptTraceSize;
   bool enable_tsc = kDefaultEnableTscValue;
   Optional<uint64_t> psb_period = kDefaultPsbPeriod;
 
   if (configuration) {
     if (StructuredData::Dictionary *dict = configuration->GetAsDictionary()) {
+      llvm::StringRef ipt_trace_size_not_parsed;
+      if (dict->GetValueForKeyAsString("iptTraceSize",
+                                       ipt_trace_size_not_parsed)) {
+        if (Optional<uint64_t> bytes =
+                ParsingUtils::ParseUserFriendlySizeExpression(
+                    ipt_trace_size_not_parsed))
+          ipt_trace_size = *bytes;
+        else
+          return createStringError(inconvertibleErrorCode(),
+                                   "iptTraceSize is wrong bytes expression");
+      } else {
         dict->GetValueForKeyAsInteger("iptTraceSize", ipt_trace_size);
+      }
+
       dict->GetValueForKeyAsBoolean("enableTsc", enable_tsc);
       dict->GetValueForKeyAsInteger("psbPeriod", psb_period);
     } else {
       return createStringError(inconvertibleErrorCode(),
                                "configuration object is not a dictionary");
     }
   }
 

lldb/source/Plugins/Trace/intel-pt/TraceIntelPTOptions.td

 include "../../../../source/Commands/OptionsBase.td"
 
 // The information of the start commands here should match the description of
 // the intel-pt section of the jLLDBTraceStart packet in the
 // lldb/docs/lldb-gdb-remote.txt documentation file. Similarly, it should match
 // the API help message of TraceIntelPT::GetStartConfigurationHelp().
 
 let Command = "thread trace start intel pt" in {
   def thread_trace_start_intel_pt_size: Option<"size", "s">,
     Group<1>,
     Arg<"Value">,
     Desc<"Trace size in bytes per thread. It must be a power of 2 greater "
          "than or equal to 4096 (2^12). The trace is circular keeping "
-         "the most recent data. Defaults to 4096 bytes.">;
+         "the most recent data. Defaults to 4096 bytes. It's possible to "
+         "specify size using multiples of unit bytes, e.g., 4KB, 1MB, 1MiB, "
+         "where 1K is 1024 bytes and 1M is 1048576 bytes.">;
   def thread_trace_start_intel_pt_tsc: Option<"tsc", "t">,
     Group<1>,
     Desc<"Enable the use of TSC timestamps. This is supported on all devices "
          "that support intel-pt.">;
   def thread_trace_start_intel_pt_psb_period: Option<"psb-period", "p">,
     Group<1>,
     Arg<"Value">,
     Desc<"This value defines the period in which PSB packets will be "

 }
 
 let Command = "process trace start intel pt" in {
   def process_trace_start_intel_pt_buffer_size: Option<"buffer-size", "s">,
     Group<1>,
     Arg<"Value">,
     Desc<"Size in bytes used by each individual per-thread or per-cpu trace "
          "buffer. It must be a power of 2 greater than or equal to 4096 (2^12) "
-         "bytes.">;
+         "bytes. It's possible to specify a unit for these bytes, like 4KB, "
+         "16KiB or 1MB. Lower case units are allowed for convenience.">;
   def process_trace_start_intel_pt_per_cpu_tracing:
     Option<"per-cpu-tracing", "c">,
     Group<1>,
     Desc<"Instead of having an individual trace buffer per thread, which uses "
          "a number trace buffers proportional to the number of running "
          "threads, this option triggers the collection on a per cpu core "
          "basis. This effectively traces the entire activity on all cpus "
          "using a limited amount of trace buffers regardless of the number of "
          "threads. This might cause data loss for less frequent threads. This "
          "option forces the capture of TSC timestamps (see --tsc). Also, this "
          "option can't be used simulatenously with any other trace sessions "
          "because of its system-wide nature.">;
-  def process_trace_start_intel_pt_process_size_limit: Option<"total-size-limit", "l">,
+  def process_trace_start_intel_pt_process_size_limit:
+    Option<"total-size-limit", "l">,
     Group<1>,
     Arg<"Value">,
     Desc<"Maximum total trace size per process in bytes. This limit applies to "
          "the sum of the sizes of all thread and cpu traces of this process, "
          "excluding the ones created with the \"thread trace start\" command. "
          "Whenever a thread is attempted to be traced due to this command and "
          "the limit would be reached, the process is stopped with a "
          "\"processor trace\" reason, so that the user can retrace the process "
-         "if needed. Defaults to 500MB.">;
+         "if needed. Defaults to 500MB. It's possible to specify a unit for "
+         "these bytes, like 4KB, 16KiB or 1MB. Lower case units are allowed "
+         "for convenience.">;
   def process_trace_start_intel_pt_tsc: Option<"tsc", "t">,
     Group<1>,
     Desc<"Enable the use of TSC timestamps. This is supported on all devices "
          "that support intel-pt.">;
   def process_trace_start_intel_pt_psb_period: Option<"psb-period", "p">,
     Group<1>,
     Arg<"Value">,
     Desc<"This value defines the period in which PSB packets will be "

lldb/test/API/commands/trace/TestTraceStartStop.py

def testStartSessionWithWrongSize(self):
             substrs=["The intel pt trace size must be a power of 2", "It was 5000"])
 
         self.traceStartThread(
             error=True, iptTraceSize=0,
             substrs=["The intel pt trace size must be a power of 2", "It was 0"])
 
         self.traceStartThread(iptTraceSize=1048576)
 
+    @testSBAPIAndCommands
+    def testStartSessionWithSizeDeclarationInUnits(self):
+        self.expect("file " + os.path.join(self.getSourceDir(), "intelpt-trace", "a.out"))
+        self.expect("b main")
+        self.expect("r")
+
+        self.traceStartThread(
+            error=True, iptTraceSize="abc",
+            substrs=["invalid bytes expression for 'abc'"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="123.12",
+            substrs=["invalid bytes expression for '123.12'"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="\"\"",
+            substrs=["invalid bytes expression for ''"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="2000B",
+            substrs=["The intel pt trace size must be a power of 2 greater than or equal to 4096 (2^12) bytes. It was 2000"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="3MB",
+            substrs=["The intel pt trace size must be a power of 2 greater than or equal to 4096 (2^12) bytes. It was 3145728"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="3MiB",
+            substrs=["The intel pt trace size must be a power of 2 greater than or equal to 4096 (2^12) bytes. It was 3145728"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="3mib",
+            substrs=["The intel pt trace size must be a power of 2 greater than or equal to 4096 (2^12) bytes. It was 3145728"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="3M",
+            substrs=["The intel pt trace size must be a power of 2 greater than or equal to 4096 (2^12) bytes. It was 3145728"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="3KB",
+            substrs=["The intel pt trace size must be a power of 2 greater than or equal to 4096 (2^12) bytes. It was 3072"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="3KiB",
+            substrs=["The intel pt trace size must be a power of 2 greater than or equal to 4096 (2^12) bytes. It was 3072"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="3K",
+            substrs=["The intel pt trace size must be a power of 2 greater than or equal to 4096 (2^12) bytes. It was 3072"])
+
+        self.traceStartThread(
+            error=True, iptTraceSize="3MS",
+            substrs=["invalid bytes expression for '3MS'"])
+
+        self.traceStartThread(iptTraceSize="1048576")
+
     @skipIf(oslist=no_match(['linux']), archs=no_match(['i386', 'x86_64']))
     def testSBAPIHelp(self):
         self.expect("file " + os.path.join(self.getSourceDir(), "intelpt-trace", "a.out"))
         self.expect("b main")
         self.expect("r")
 
         help = self.getTraceOrCreate().GetStartConfigurationHelp()
         self.assertIn("iptTraceSize", help)