Add libc++ data formatter for std::function
- Added LibcxxFunctionSummaryProvider
- Removed LibcxxFunctionFrontEnd
- Modified data formatter tests to test new summary functionality
Patch by Shafik Yaghmour!
Differential Revision: https://reviews.llvm.org/D50864
llvm-svn: 340543
diff --git a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
index 56dce5c..27b0f11 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxx.cpp
@@ -12,6 +12,7 @@
// C Includes
// C++ Includes
// Other libraries and framework includes
+#include "llvm/ADT/ScopeExit.h"
// Project includes
#include "lldb/Core/Debugger.h"
#include "lldb/Core/FormatEntity.h"
@@ -23,6 +24,7 @@
#include "lldb/DataFormatters/VectorIterator.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Target/ProcessStructReader.h"
+#include "lldb/Target/SectionLoadList.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/DataBufferHeap.h"
#include "lldb/Utility/Endian.h"
@@ -55,6 +57,226 @@
return true;
}
+bool lldb_private::formatters::LibcxxFunctionSummaryProvider(
+ ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
+
+ ValueObjectSP valobj_sp(valobj.GetNonSyntheticValue());
+
+ if (!valobj_sp)
+ return false;
+
+ // Member __f_ has type __base*, the contents of which will hold:
+ // 1) a vtable entry which may hold type information needed to discover the
+ // lambda being called
+ // 2) possibly hold a pointer to the callable object
+ // e.g.
+ //
+ // (lldb) frame var -R f_display
+ // (std::__1::function<void (int)>) f_display = {
+ // __buf_ = {
+ // …
+ // }
+ // __f_ = 0x00007ffeefbffa00
+ // }
+ // (lldb) memory read -fA 0x00007ffeefbffa00
+ // 0x7ffeefbffa00: ... `vtable for std::__1::__function::__func<void (*) ...
+ // 0x7ffeefbffa08: ... `print_num(int) at std_function_cppreference_exam ...
+ //
+ // We will be handling five cases below, std::function is wrapping:
+ //
+ // 1) a lambda we know at compile time. We will obtain the name of the lambda
+ // from the first template pameter from __func's vtable. We will look up
+ // the lambda's operator()() and obtain the line table entry.
+ // 2) a lambda we know at runtime. A pointer to the lambdas __invoke method
+ // will be stored after the vtable. We will obtain the lambdas name from
+ // this entry and lookup operator()() and obtain the line table entry.
+ // 3) a callable object via operator()(). We will obtain the name of the
+ // object from the first template parameter from __func's vtable. We will
+ // look up the objectc operator()() and obtain the line table entry.
+ // 4) a member function. A pointer to the function will stored after the
+ // we will obtain the name from this pointer.
+ // 5) a free function. A pointer to the function will stored after the vtable
+ // we will obtain the name from this pointer.
+ ValueObjectSP member__f_(
+ valobj_sp->GetChildMemberWithName(ConstString("__f_"), true));
+ lldb::addr_t member__f_pointer_value = member__f_->GetValueAsUnsigned(0);
+
+ ExecutionContext exe_ctx(valobj_sp->GetExecutionContextRef());
+ Process *process = exe_ctx.GetProcessPtr();
+
+ if (process == nullptr)
+ return false;
+
+ uint32_t address_size = process->GetAddressByteSize();
+ Status status;
+
+ // First item pointed to by __f_ should be the pointer to the vtable for
+ // a __base object.
+ lldb::addr_t vtable_address =
+ process->ReadPointerFromMemory(member__f_pointer_value, status);
+
+ if (status.Fail())
+ return false;
+
+ bool found_wrapped_function = false;
+
+ // Using scoped exit so we can use early return and still execute the default
+ // action in case we don't find the wrapper function. Otherwise we can't use
+ // early exit without duplicating code.
+ auto default_print_on_exit = llvm::make_scope_exit(
+ [&found_wrapped_function, &stream, &member__f_pointer_value]() {
+ if (!found_wrapped_function)
+ stream.Printf(" __f_ = %llu", member__f_pointer_value);
+ });
+
+ lldb::addr_t address_after_vtable = member__f_pointer_value + address_size;
+ // As commened above we may not have a function pointer but if we do we will
+ // need it.
+ lldb::addr_t possible_function_address =
+ process->ReadPointerFromMemory(address_after_vtable, status);
+
+ if (status.Fail())
+ return false;
+
+ Target &target = process->GetTarget();
+
+ if (target.GetSectionLoadList().IsEmpty())
+ return false;
+
+ Address vtable_addr_resolved;
+ SymbolContext sc;
+ Symbol *symbol;
+
+ if (!target.GetSectionLoadList().ResolveLoadAddress(vtable_address,
+ vtable_addr_resolved))
+ return false;
+
+ target.GetImages().ResolveSymbolContextForAddress(
+ vtable_addr_resolved, eSymbolContextEverything, sc);
+ symbol = sc.symbol;
+
+ if (symbol == NULL)
+ return false;
+
+ llvm::StringRef vtable_name(symbol->GetName().GetCString());
+ bool found_expected_start_string =
+ vtable_name.startswith("vtable for std::__1::__function::__func<");
+
+ if (!found_expected_start_string)
+ return false;
+
+ // Given case 1 or 3 we have a vtable name, we are want to extract the first
+ // template parameter
+ //
+ // ... __func<main::$_0, std::__1::allocator<main::$_0> ...
+ // ^^^^^^^^^
+ //
+ // We do this by find the first < and , and extracting in between.
+ //
+ // This covers the case of the lambda known at compile time.
+ //
+ size_t first_open_angle_bracket = vtable_name.find('<') + 1;
+ size_t first_comma = vtable_name.find_first_of(',');
+
+ llvm::StringRef first_template_parameter =
+ vtable_name.slice(first_open_angle_bracket, first_comma);
+
+ Address function_address_resolved;
+
+ // Setup for cases 2, 4 and 5 we have a pointer to a function after the
+ // vtable. We will use a process of elimination to drop through each case
+ // and obtain the data we need.
+ if (target.GetSectionLoadList().ResolveLoadAddress(
+ possible_function_address, function_address_resolved)) {
+ target.GetImages().ResolveSymbolContextForAddress(
+ function_address_resolved, eSymbolContextEverything, sc);
+ symbol = sc.symbol;
+ }
+
+ auto get_name = [&first_template_parameter, &symbol]() {
+ // Given case 1:
+ //
+ // main::$_0
+ //
+ // we want to append ::operator()()
+ if (first_template_parameter.contains("$_"))
+ return llvm::Regex::escape(first_template_parameter.str()) +
+ R"(::operator\(\)\(.*\))";
+
+ if (symbol != NULL &&
+ symbol->GetName().GetStringRef().contains("__invoke")) {
+
+ llvm::StringRef symbol_name = symbol->GetName().GetStringRef();
+ size_t pos2 = symbol_name.find_last_of(':');
+
+ // Given case 2:
+ //
+ // main::$_1::__invoke(...)
+ //
+ // We want to slice off __invoke(...) and append operator()()
+ std::string lambda_operator =
+ llvm::Regex::escape(symbol_name.slice(0, pos2 + 1).str()) +
+ R"(operator\(\)\(.*\))";
+
+ return lambda_operator;
+ }
+
+ // Case 3
+ return first_template_parameter.str() + R"(::operator\(\)\(.*\))";
+ ;
+ };
+
+ std::string func_to_match = get_name();
+
+ SymbolContextList scl;
+
+ target.GetImages().FindFunctions(RegularExpression{func_to_match}, true, true,
+ true, scl);
+
+ // Case 1,2 or 3
+ if (scl.GetSize() >= 1) {
+ SymbolContext sc2 = scl[0];
+
+ AddressRange range;
+ sc2.GetAddressRange(eSymbolContextEverything, 0, false, range);
+
+ Address address = range.GetBaseAddress();
+
+ Address addr;
+ if (target.ResolveLoadAddress(address.GetCallableLoadAddress(&target),
+ addr)) {
+ LineEntry line_entry;
+ addr.CalculateSymbolContextLineEntry(line_entry);
+
+ found_wrapped_function = true;
+ if (first_template_parameter.contains("$_") ||
+ (symbol != NULL &&
+ symbol->GetName().GetStringRef().contains("__invoke"))) {
+ // Case 1 and 2
+ stream.Printf(" Lambda in File %s at Line %u",
+ line_entry.file.GetFilename().GetCString(),
+ line_entry.line);
+ } else {
+ // Case 3
+ stream.Printf(" Function in File %s at Line %u",
+ line_entry.file.GetFilename().GetCString(),
+ line_entry.line);
+ }
+
+ return true;
+ }
+ }
+
+ // Case 4 or 5
+ if (!symbol->GetName().GetStringRef().startswith("vtable for")) {
+ found_wrapped_function = true;
+ stream.Printf(" Function = %s ", symbol->GetName().GetCString());
+ return true;
+ }
+
+ return false;
+}
+
bool lldb_private::formatters::LibcxxSmartPointerSummaryProvider(
ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
ValueObjectSP valobj_sp(valobj.GetNonSyntheticValue());
@@ -588,22 +810,3 @@
return true;
}
-
-class LibcxxFunctionFrontEnd : public SyntheticValueProviderFrontEnd {
-public:
- LibcxxFunctionFrontEnd(ValueObject &backend)
- : SyntheticValueProviderFrontEnd(backend) {}
-
- lldb::ValueObjectSP GetSyntheticValue() override {
- static ConstString g___f_("__f_");
- return m_backend.GetChildMemberWithName(g___f_, true);
- }
-};
-
-SyntheticChildrenFrontEnd *
-lldb_private::formatters::LibcxxFunctionFrontEndCreator(
- CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
- if (valobj_sp)
- return new LibcxxFunctionFrontEnd(*valobj_sp);
- return nullptr;
-}