[lldb][libc++] Adds chrono data formatters.

[Mordante]

Summary

This adds the data formatters for chrono duration typedefs.

[aprantl]

lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp

996

Nice!

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/chrono/TestDataFormatterLibcxxChrono.py

23

You probably copied & pasted this — this is no longer needed since every test function is now running in its own instance.

33

This is not guaranteed behavior and is highly specific on the actual compiler. I would probably just remove this first sets of tests.

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/chrono/main.cpp

17

can you change this to a function call like

std::cout()<<"break here\n";

It's not guaranteed that all compilers actually generate code for this line that results in a breakpoint opportunity.

[kastiglione]

Thanks for doing this!

Question to all: Should the summary string include the unit? lldb doesn't always show the type, so it could help comprehension if the unit is included. For example 60s instead of 60.

lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp

986–993

there's some regex grouping that doesn't seem to be needed.

[Mordante]

In D159127#4626311, @kastiglione wrote:

Thanks for doing this!

Question to all: Should the summary string include the unit? lldb doesn't always show the type, so it could help comprehension if the unit is included. For example 60s instead of 60.

I was wondering about that too, but I wasn't sure whether that was wanted. If we do that what do you prefer for micro seconds us or µs. The latter uses Unicode. The C++ Standard allows both http://eel.is/c++draft/time.duration.io.

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/chrono/TestDataFormatterLibcxxChrono.py

23

I indeed copy-pasted the vector code; it's the first time I look at these formatters.

[Mordante]

lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp

986–993

Earlier testing without grouping didn't work. Since the next iteration uses units here is a regex per type.

[Mordante]

Address review comments.

[Michael137]

Was looking at leftover reviews, would be nice to land this

[Mordante]

In D159127#4654774, @Michael137 wrote:

Was looking at leftover reviews, would be nice to land this

Thanks for the review!

[aprantl]

@Mordante @Michael137 This seems to fail on older versions of compiler/libcxx https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake-matrix/7247/ You can probably fix this by just requiring a minimum clang version in the tests

[Michael137]

In D159127#4655450, @aprantl wrote:

@Mordante @Michael137 This seems to fail on older versions of compiler/libcxx https://green.lab.llvm.org/green/view/LLDB/job/lldb-cmake-matrix/7247/ You can probably fix this by just requiring a minimum clang version in the tests

https://github.com/llvm/llvm-project/pull/70544

lldb/source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp

AddCXXSynthetic(
       true);
 
   AddCXXSynthetic(cpp_category_sp,
                   lldb_private::formatters::
                       LibCxxUnorderedMapIteratorSyntheticFrontEndCreator,
                   "std::unordered_map iterator synthetic children",
                   "^std::__[[:alnum:]]+::__hash_map_(const_)?iterator<.+>$",
                   stl_synth_flags, true);
+  // Chrono duration typedefs
+  cpp_category_sp->AddTypeSummary(
+      "^std::__[[:alnum:]]+::chrono::"
+      "(((nano)|(micro)|(milli)|())seconds)|"
+      "(minutes)|"
+      "(hours)|"
+      "(days)|"
+      "(weeks)|"
+      "(months)|"
+      "(years)",
+      eFormatterMatchRegex,
+      TypeSummaryImplSP(new StringSummaryFormat(
+          eTypeOptionHideChildren | eTypeOptionHideValue, "${var.__rep_}")));
 }
 
 static void LoadLibStdcppFormatters(lldb::TypeCategoryImplSP cpp_category_sp) {
   if (!cpp_category_sp)
     return;
 
   TypeSummaryImpl::Flags stl_summary_flags;
   stl_summary_flags.SetCascades(true)

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/chrono/Makefile

+CXX_SOURCES := main.cpp
+
+USE_LIBCPP := 1
+
+CXXFLAGS_EXTRAS := -std=c++20
+include Makefile.rules

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/chrono/TestDataFormatterLibcxxChrono.py

+"""
+Test lldb data formatter subsystem.
+"""
+
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class LibcxxChronoDataFormatterTestCase(TestBase):
+    @add_test_categories(["libc++"])
+    def test_with_run_command(self):
+        """Test that that file and class static variables display correctly."""
+        self.build()
+        (self.target, process, thread, bkpt) = lldbutil.run_to_source_breakpoint(
+            self, "break here", lldb.SBFileSpec("main.cpp", False)
+        )
+
+        # This is the function to remove the custom formats in order to have a
+        # clean slate for the next test case.
+        def cleanup():
+            self.runCmd("type format clear", check=False)
+            self.runCmd("type summary clear", check=False)
+            self.runCmd("type filter clear", check=False)
+            self.runCmd("type synth clear", check=False)
+            self.runCmd("settings set target.max-children-count 256", check=False)
+
+        # Execute the cleanup function during test case tear down.
+        self.addTearDownHook(cleanup)
+
+        # empty vectors (and storage pointers SHOULD BOTH BE NULL..)
+        self.expect("frame variable ns", substrs=["ns = 0"])
+        self.expect("frame variable us", substrs=["us = 0"])
+        self.expect("frame variable ms", substrs=["ms = 0"])
+        self.expect("frame variable s", substrs=["s = 0"])
+        self.expect("frame variable min", substrs=["min = 0"])
+        self.expect("frame variable h", substrs=["h = 0"])
+
+        self.expect("frame variable d", substrs=["d = 0"])
+        self.expect("frame variable w", substrs=["w = 0"])
+        self.expect("frame variable m", substrs=["m = 0"])
+        self.expect("frame variable y", substrs=["y = 0"])
+
+        lldbutil.continue_to_breakpoint(process, bkpt)
+        self.expect("frame variable ns", substrs=["ns = 1"])
+        self.expect("frame variable us", substrs=["us = 12"])
+        self.expect("frame variable ms", substrs=["ms = 123"])
+        self.expect("frame variable s", substrs=["s = 1234"])
+        self.expect("frame variable min", substrs=["min = 12345"])
+        self.expect("frame variable h", substrs=["h = 123456"])
+
+        self.expect("frame variable d", substrs=["d = 654321"])
+        self.expect("frame variable w", substrs=["w = 54321"])
+        self.expect("frame variable m", substrs=["m = 4321"])
+        self.expect("frame variable y", substrs=["y = 321"])
+

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libcxx/chrono/main.cpp

+#include <chrono>
+
+int main() {
+  // break here
+  std::chrono::nanoseconds ns{1};
+  std::chrono::microseconds us{12};
+  std::chrono::milliseconds ms{123};
+  std::chrono::seconds s{1234};
+  std::chrono::minutes min{12345};
+  std::chrono::hours h{123456};
+
+  std::chrono::days d{654321};
+  std::chrono::weeks w{54321};
+  std::chrono::months m{4321};
+  std::chrono::years y{321};
+
+  return 0; // break here
+}