vsk updated this revision to Diff 160224.
vsk added a comment.
Herald added a subscriber: mgrang.
Rebase, and update the patch to use DW_AT_call_return_pc information.
https://reviews.llvm.org/D50478
Files:
lldb/include/lldb/Symbol/Block.h
lldb/include/lldb/Symbol/Function.h
lldb/include/lldb/Symbol/SymbolFile.h
lldb/include/lldb/Target/StackFrame.h
lldb/include/lldb/Target/StackFrameList.h
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/TODO
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail.cc
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail2.cc
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail3.cc
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail4.cc
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail5.cc
lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/test.sh
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
lldb/source/Symbol/Block.cpp
lldb/source/Symbol/Function.cpp
lldb/source/Target/StackFrameList.cpp
Index: lldb/source/Target/StackFrameList.cpp
===================================================================
--- lldb/source/Target/StackFrameList.cpp
+++ lldb/source/Target/StackFrameList.cpp
@@ -27,6 +27,7 @@
#include "lldb/Target/Thread.h"
#include "lldb/Target/Unwind.h"
#include "lldb/Utility/Log.h"
+#include "llvm/ADT/SmallPtrSet.h"
//#define DEBUG_STACK_FRAMES 1
@@ -240,6 +241,134 @@
m_frames.resize(num_frames);
}
+/// Find the unique path through the call graph from \p begin (at PC offset
+/// \p call_pc) to \p end. On success this path is stored into \p path, and on
+/// failure \p path is unchanged.
+static void FindInterveningFrames(Function &begin, Function &end,
+ addr_t call_pc, std::vector<Function *> &path,
+ ModuleList &images, Log *log) {
+ LLDB_LOG(log, "Finding frames between {0} and {1}, call-pc={2:x}",
+ begin.GetDisplayName(), end.GetDisplayName(), call_pc);
+
+ // Find a non-tail calling edge with the first return PC greater than the
+ // call PC.
+ auto first_level_edges = begin.GetCallEdges();
+ auto first_edge_it =
+ std::lower_bound(first_level_edges.begin(), first_level_edges.end(),
+ call_pc, [=](const CallEdge &edge, addr_t target_pc) {
+ return edge.GetReturnPCAddress() < target_pc;
+ });
+ if (first_edge_it == first_level_edges.end())
+ return;
+ CallEdge &first_edge = const_cast<CallEdge &>(*first_edge_it);
+ if (first_edge.GetReturnPCAddress() == LLDB_INVALID_ADDRESS)
+ return;
+
+ // The first callee may not be resolved, or there may be nothing to fill in.
+ Function *first_callee = first_edge.GetCallee(images);
+ if (!first_callee || first_callee == &end)
+ return;
+
+ // Run DFS on the tail-calling edges out of the first callee to find \p end.
+ struct DFS {
+ std::vector<Function *> active_path = {};
+ llvm::SmallPtrSet<Function *, 2> visited_nodes = {};
+ bool ambiguous = false;
+ Function *end;
+ ModuleList &images;
+
+ DFS(Function *end, ModuleList &images) : end(end), images(images) {}
+
+ void search(Function *first_callee, std::vector<Function *> &path) {
+ if (dfs(first_callee) && !ambiguous)
+ path = std::move(active_path);
+ }
+
+ bool dfs(Function *callee) {
+ if (callee == end)
+ return true;
+
+ // Terminate the search when tail recursion is detected.
+ if (!visited_nodes.insert(callee).second) {
+ ambiguous = true;
+ return false;
+ }
+
+ active_path.push_back(callee);
+ for (CallEdge &edge : callee->GetTailCallingEdges()) {
+ Function *next_callee = edge.GetCallee(images);
+ if (!next_callee)
+ continue;
+
+ if (dfs(next_callee) && !ambiguous)
+ return true;
+
+ if (ambiguous)
+ return false;
+ }
+ active_path.pop_back();
+ return false;
+ }
+ };
+
+ DFS(&end, images).search(first_callee, path);
+}
+
+/// Given that \p next_frame will be appended to the frame list, synthesize
+/// tail call frames between the current end of the list and \p next_frame.
+/// If any frames are added, adjust the frame index of \p next_frame.
+void StackFrameList::SynthesizeTailCallFrames(StackFrame &next_frame) {
+ lldb::RegisterContextSP next_reg_ctx_sp = next_frame.GetRegisterContext();
+ if (!next_reg_ctx_sp)
+ return;
+
+ Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
+
+ assert(!m_frames.empty() && "Cannot synthesize frames in an empty stack");
+ StackFrame &prev_frame = *m_frames.back().get();
+
+ // Find the functions prev_frame and next_frame are stopped in. The function
+ // objects are needed to search the lazy call graph for intervening frames.
+ Function *prev_func =
+ prev_frame.GetSymbolContext(eSymbolContextFunction).function;
+ if (!prev_func)
+ return;
+ Function *next_func =
+ next_frame.GetSymbolContext(eSymbolContextFunction).function;
+ if (!next_func)
+ return;
+
+ // Try to find the unique sequence of (tail) calls which led from next_frame
+ // to prev_frame.
+ std::vector<Function *> path;
+ addr_t call_pc = next_reg_ctx_sp->GetPC();
+ ModuleList &images = next_frame.CalculateTarget()->GetImages();
+ FindInterveningFrames(*next_func, *prev_func, call_pc, path, images, log);
+
+ // Push synthetic tail call frames.
+ for (Function *callee : llvm::reverse(path)) {
+ uint32_t frame_idx = m_frames.size();
+ uint32_t concrete_frame_idx = next_frame.GetConcreteFrameIndex();
+ addr_t cfa = LLDB_INVALID_ADDRESS;
+ bool cfa_is_valid = false;
+ addr_t pc = callee->GetAddressRange().GetBaseAddress().GetOffset();
+ uint32_t stop_id = 0;
+ bool stop_id_is_valid = false;
+ bool is_history_frame = false;
+ SymbolContext sc;
+ callee->CalculateSymbolContext(&sc);
+ StackFrameSP synth_frame{new StackFrame(
+ m_thread.shared_from_this(), frame_idx, concrete_frame_idx, cfa,
+ cfa_is_valid, pc, stop_id, stop_id_is_valid, is_history_frame, &sc)};
+ m_frames.push_back(synth_frame);
+ LLDB_LOG(log, "Pushed frame {0}", callee->GetDisplayName());
+ }
+
+ // If any frames were created, adjust next_frame's index.
+ if (!path.empty())
+ next_frame.SetFrameIndex(m_frames.size());
+}
+
void StackFrameList::GetFramesUpTo(uint32_t end_idx) {
// Do not fetch frames for an invalid thread.
if (!m_thread.IsValid())
@@ -320,6 +449,12 @@
unwind_frame_sp.reset(new StackFrame(
m_thread.shared_from_this(), m_frames.size(), idx, cfa, cfa_is_valid,
pc, 0, stop_id_is_valid, is_history_frame, nullptr));
+
+ // Create synthetic tail call frames between the previous frame and the
+ // newly-found frame. The new frame's index may change after this call,
+ // although its concrete index will stay the same.
+ SynthesizeTailCallFrames(*unwind_frame_sp.get());
+
m_frames.push_back(unwind_frame_sp);
}
Index: lldb/source/Symbol/Function.cpp
===================================================================
--- lldb/source/Symbol/Function.cpp
+++ lldb/source/Symbol/Function.cpp
@@ -10,14 +10,16 @@
#include "lldb/Symbol/Function.h"
#include "lldb/Core/Disassembler.h"
#include "lldb/Core/Module.h"
+#include "lldb/Core/ModuleList.h"
#include "lldb/Core/Section.h"
#include "lldb/Host/Host.h"
#include "lldb/Symbol/CompileUnit.h"
#include "lldb/Symbol/CompilerType.h"
#include "lldb/Symbol/LineTable.h"
#include "lldb/Symbol/SymbolFile.h"
#include "lldb/Symbol/SymbolVendor.h"
#include "lldb/Target/Language.h"
+#include "lldb/Utility/Log.h"
#include "llvm/Support/Casting.h"
using namespace lldb;
@@ -128,6 +130,54 @@
return FunctionInfo::MemorySize() + m_mangled.MemorySize();
}
+//----------------------------------------------------------------------
+//
+//----------------------------------------------------------------------
+CallEdge::CallEdge(const char *mangled_name, lldb::addr_t return_pc)
+ : resolved(false), return_pc(return_pc) {
+ lazy_callee.mangled_name = mangled_name;
+}
+
+void CallEdge::ParseSymbolFileAndResolve(ModuleList &images) {
+ if (resolved)
+ return;
+
+ Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
+ LLDB_LOG(log, "CallEdge: Lazily parsing the call graph for {0}",
+ lazy_callee.mangled_name);
+
+ lazy_callee.def = [&]() -> Function * {
+ ConstString callee_name{lazy_callee.mangled_name};
+ SymbolContextList sc_list;
+ size_t num_matches =
+ images.FindFunctionSymbols(callee_name, eFunctionNameTypeAuto, sc_list);
+ if (num_matches != 1 || !sc_list[0].symbol) {
+ LLDB_LOG(log, "CallEdge: Found {0} symbols for {1}, cannot resolve it",
+ num_matches, callee_name);
+ return nullptr;
+ }
+ Address callee_addr = sc_list[0].symbol->GetAddress();
+ if (!callee_addr.IsValid()) {
+ LLDB_LOG(log, "CallEdge: Invalid symbol address");
+ return nullptr;
+ }
+ Function *f = callee_addr.CalculateSymbolContextFunction();
+ if (!f) {
+ LLDB_LOG(log, "CallEdge: Could not find complete function");
+ return nullptr;
+ }
+ return f;
+ }();
+ resolved = true;
+}
+
+Function *CallEdge::GetCallee(ModuleList &images) {
+ ParseSymbolFileAndResolve(images);
+ return lazy_callee.def;
+}
+
+lldb::addr_t CallEdge::GetReturnPCAddress() const { return return_pc; }
+
//----------------------------------------------------------------------
//
//----------------------------------------------------------------------
@@ -192,6 +242,38 @@
}
}
+llvm::MutableArrayRef<CallEdge> Function::GetCallEdges() {
+ if (m_call_edges_resolved)
+ return m_call_edges;
+
+ m_call_edges_resolved = true;
+
+ // Find the SymbolFile which provided this function's definition.
+ Block &block = GetBlock(/*can_create*/true);
+ SymbolFile *sym_file = block.GetSymbolFile();
+ if (!sym_file)
+ return llvm::None;
+
+ // Lazily read call site information from the SymbolFile.
+ m_call_edges = sym_file->ParseCallEdgesInFunction(GetID());
+
+ // Sort the call edges to speed up return_pc lookups.
+ std::sort(m_call_edges.begin(), m_call_edges.end(),
+ [](const CallEdge &LHS, const CallEdge &RHS) {
+ return LHS.GetReturnPCAddress() < RHS.GetReturnPCAddress();
+ });
+
+ return m_call_edges;
+}
+
+llvm::MutableArrayRef<CallEdge> Function::GetTailCallingEdges() {
+ // Call edges are sorted by return PC, and tail calling edges have invalid
+ // return PCs. Find them at the end of the list.
+ return GetCallEdges().drop_until([](const CallEdge &edge) {
+ return edge.GetReturnPCAddress() == LLDB_INVALID_ADDRESS;
+ });
+}
+
Block &Function::GetBlock(bool can_create) {
if (!m_block.BlockInfoHasBeenParsed() && can_create) {
SymbolContext sc;
Index: lldb/source/Symbol/Block.cpp
===================================================================
--- lldb/source/Symbol/Block.cpp
+++ lldb/source/Symbol/Block.cpp
@@ -444,19 +444,16 @@
return num_variables_added;
}
-CompilerDeclContext Block::GetDeclContext() {
- ModuleSP module_sp = CalculateSymbolContextModule();
-
- if (module_sp) {
- SymbolVendor *sym_vendor = module_sp->GetSymbolVendor();
-
- if (sym_vendor) {
- SymbolFile *sym_file = sym_vendor->GetSymbolFile();
+SymbolFile *Block::GetSymbolFile() {
+ if (ModuleSP module_sp = CalculateSymbolContextModule())
+ if (SymbolVendor *sym_vendor = module_sp->GetSymbolVendor())
+ return sym_vendor->GetSymbolFile();
+ return nullptr;
+}
- if (sym_file)
- return sym_file->GetDeclContextForUID(GetID());
- }
- }
+CompilerDeclContext Block::GetDeclContext() {
+ if (SymbolFile *sym_file = GetSymbolFile())
+ return sym_file->GetDeclContextForUID(GetID());
return CompilerDeclContext();
}
Index: lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
===================================================================
--- lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
+++ lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.h
@@ -316,6 +316,9 @@
DIEInDeclContext(const lldb_private::CompilerDeclContext *parent_decl_ctx,
const DWARFDIE &die);
+ std::vector<lldb_private::CallEdge>
+ ParseCallEdgesInFunction(UserID func_id) override;
+
void Dump(lldb_private::Stream &s) override;
protected:
Index: lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
===================================================================
--- lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
+++ lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp
@@ -3736,6 +3736,59 @@
return vars_added;
}
+/// Collect call graph edges present in a function DIE.
+static std::vector<lldb_private::CallEdge>
+CollectCallEdges(DWARFDIE function_die) {
+ // Check if the function has a supported call site-related attribute.
+ // TODO: In the future it may be worthwhile to support call_all_source_calls.
+ uint64_t has_call_edges =
+ function_die.GetAttributeValueAsUnsigned(DW_AT_call_all_calls, 0);
+ if (!has_call_edges)
+ return {};
+
+ Log *log(lldb_private::GetLogIfAllCategoriesSet(LIBLLDB_LOG_STEP));
+ LLDB_LOG(log, "CollectCallEdges: Found call site info in {0}",
+ function_die.GetPubname());
+
+ // Scan the DIE for TAG_call_site entries.
+ // TODO: A recursive scan of all blocks in the subprogram is needed in order
+ // to be DWARF5-compliant. This may need to be done lazily to be performant.
+ // For now, assume that all entries are nested directly under the subprogram
+ // (this is the kind of DWARF LLVM produces) and parse them eagerly.
+ std::vector<CallEdge> call_edges;
+ for (DWARFDIE child = function_die.GetFirstChild(); child.IsValid();
+ child = child.GetSibling()) {
+ if (child.Tag() != DW_TAG_call_site)
+ continue;
+
+ // Extract DW_AT_call_origin (the call target's DIE).
+ DWARFDIE call_origin = child.GetReferencedDIE(DW_AT_call_origin);
+ if (!call_origin.IsValid()) {
+ LLDB_LOG(log, "CollectCallEdges: Invalid call origin in {0}",
+ function_die.GetPubname());
+ continue;
+ }
+
+ // Extract DW_AT_call_return_pc (the PC the call returns to) if it's
+ // available.
+ addr_t return_pc = child.GetAttributeValueAsAddress(DW_AT_call_return_pc,
+ LLDB_INVALID_ADDRESS);
+
+ LLDB_LOG(log, "CollectCallEdges: Found call origin: {0} (return PC = {1})",
+ call_origin.GetPubname(), return_pc);
+ call_edges.emplace_back(call_origin.GetMangledName(), return_pc);
+ }
+ return call_edges;
+}
+
+std::vector<lldb_private::CallEdge>
+SymbolFileDWARF::ParseCallEdgesInFunction(UserID func_id) {
+ DWARFDIE func_die = GetDIEFromUID(func_id.GetID());
+ if (func_die.IsValid())
+ return CollectCallEdges(func_die);
+ return {};
+}
+
//------------------------------------------------------------------
// PluginInterface protocol
//------------------------------------------------------------------
Index: lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/test.sh
===================================================================
--- /dev/null
+++ lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/test.sh
@@ -0,0 +1,12 @@
+#!/bin/bash -x
+
+BIN=/Users/vsk/src/builds/llvm-project-tailcall-RA/bin/
+CXX=$BIN/clang++
+LLDB=$BIN/lldb
+
+for F in $(ls *.cc); do
+ $CXX $F -o $F.out \
+ -g -mllvm -callsite-debuginfo-experimental=true -O2
+
+ $LLDB -o "b sink" -o "r" -o "log enable -f $F.log lldb step" -o "bt" -o "quit" $F.out
+done
Index: lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail5.cc
===================================================================
--- /dev/null
+++ lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail5.cc
@@ -0,0 +1,6 @@
+volatile int x;
+void __attribute__((noinline)) sink() { x++; }
+void __attribute__((noinline)) D() { sink(); /* tail */ }
+void __attribute__((disable_tail_calls, noinline)) C() { D(); /* regular */ }
+void __attribute__((noinline)) B() { C(); /* tail */ }
+int __attribute__((disable_tail_calls)) main() { B(); /* regular */ }
Index: lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail4.cc
===================================================================
--- /dev/null
+++ lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail4.cc
@@ -0,0 +1,5 @@
+volatile int x;
+void __attribute__((noinline)) sink() { x++; } // Two possible paths to sink.
+void __attribute__((noinline)) foo() { sink(); /* tail */ }
+void __attribute__((noinline)) bar() { sink(); /* tail */ }
+int __attribute__((disable_tail_calls)) main() { foo(); bar(); /* regular */ }
Index: lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail3.cc
===================================================================
--- /dev/null
+++ lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail3.cc
@@ -0,0 +1,5 @@
+volatile int x;
+void __attribute__((noinline)) sink() { x++; }
+void __attribute__((disable_tail_calls, noinline)) bar() { sink(); /* regular */ }
+void __attribute__((noinline)) foo() { bar(); /* tail */ }
+int __attribute__((disable_tail_calls)) main() { foo(); /* regular */ }
Index: lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail2.cc
===================================================================
--- /dev/null
+++ lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail2.cc
@@ -0,0 +1,8 @@
+volatile int x;
+void __attribute__((noinline)) sink() { x++; }
+void __attribute__((noinline)) bar() { x++; }
+void __attribute__((noinline)) foo() {
+ bar(); /* tail */
+ sink(); /* tail */
+}
+int __attribute__((disable_tail_calls)) main() { foo(); /* regular */}
Index: lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail.cc
===================================================================
--- /dev/null
+++ lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/tail.cc
@@ -0,0 +1,20 @@
+volatile int x;
+
+void __attribute__((noinline)) sink() {
+ // The stack just contains a return address inside of main().
+ //
+ // Note that it wouldn't be possible to disambiguate sink() from another
+ // immediate callee of bar() without DW_AT_return_pc.
+ x++;
+}
+
+void __attribute__((noinline)) bar() {
+ // Note that no return address in sink() is pushed onto the stack.
+ sink(); // tail (`jmp _sink`)
+}
+
+int main() {
+ bar(); // tail (`callq _bar`)
+ bar(); // tail (`callq _bar`)
+ return 0;
+}
Index: lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/TODO
===================================================================
--- /dev/null
+++ lldb/packages/Python/lldbsuite/test/functionalities/tail_call_frames/TODO
@@ -0,0 +1,4 @@
+I've updated this to use DW_AT_call_return_pc information. Now, the missing
+pieces are tests and better pretty-printing of synthetic frames. Re: testing,
+particular emphasis is needed on tail recursion, and for functions with more
+than one tail call (e.g https://godbolt.org/g/24DSdH).
Index: lldb/include/lldb/Target/StackFrameList.h
===================================================================
--- lldb/include/lldb/Target/StackFrameList.h
+++ lldb/include/lldb/Target/StackFrameList.h
@@ -99,6 +99,8 @@
void GetOnlyConcreteFramesUpTo(uint32_t end_idx, Unwind *unwinder);
+ void SynthesizeTailCallFrames(StackFrame &next_frame);
+
bool GetAllFramesFetched() { return m_concrete_frames_fetched == UINT32_MAX; }
void SetAllFramesFetched() { m_concrete_frames_fetched = UINT32_MAX; }
Index: lldb/include/lldb/Target/StackFrame.h
===================================================================
--- lldb/include/lldb/Target/StackFrame.h
+++ lldb/include/lldb/Target/StackFrame.h
@@ -412,6 +412,11 @@
//------------------------------------------------------------------
uint32_t GetFrameIndex() const;
+ //------------------------------------------------------------------
+ /// Set this frame's synthetic frame index.
+ //------------------------------------------------------------------
+ void SetFrameIndex(uint32_t index) { m_frame_index = index; }
+
//------------------------------------------------------------------
/// Query this frame to find what frame it is in this Thread's
/// StackFrameList, not counting inlined frames.
Index: lldb/include/lldb/Symbol/SymbolFile.h
===================================================================
--- lldb/include/lldb/Symbol/SymbolFile.h
+++ lldb/include/lldb/Symbol/SymbolFile.h
@@ -14,6 +14,7 @@
#include "lldb/Symbol/CompilerDecl.h"
#include "lldb/Symbol/CompilerDeclContext.h"
#include "lldb/Symbol/CompilerType.h"
+#include "lldb/Symbol/Function.h"
#include "lldb/Symbol/Type.h"
#include "lldb/lldb-private.h"
@@ -194,6 +195,10 @@
ObjectFile *GetObjectFile() { return m_obj_file; }
const ObjectFile *GetObjectFile() const { return m_obj_file; }
+ virtual std::vector<CallEdge> ParseCallEdgesInFunction(UserID func_id) {
+ return {};
+ }
+
//------------------------------------------------------------------
/// Notify the SymbolFile that the file addresses in the Sections
/// for this module have been changed.
Index: lldb/include/lldb/Symbol/Function.h
===================================================================
--- lldb/include/lldb/Symbol/Function.h
+++ lldb/include/lldb/Symbol/Function.h
@@ -16,6 +16,7 @@
#include "lldb/Symbol/Block.h"
#include "lldb/Symbol/Declaration.h"
#include "lldb/Utility/UserID.h"
+#include "llvm/ADT/ArrayRef.h"
namespace lldb_private {
@@ -290,6 +291,49 @@
Declaration m_call_decl;
};
+class Function;
+
+//----------------------------------------------------------------------
+/// @class CallEdge Function.h "lldb/Symbol/Function.h"
+///
+/// Represent a call made within a Function. This can be used to find a path
+/// in the call graph between two functions.
+//----------------------------------------------------------------------
+class CallEdge {
+public:
+ CallEdge(const char *mangled_name, lldb::addr_t return_pc);
+
+ CallEdge(CallEdge &&) = default;
+ CallEdge &operator=(CallEdge &&) = default;
+
+ /// Get the callee's definition.
+ ///
+ /// Note that this might lazily invoke the DWARF parser.
+ Function *GetCallee(ModuleList &images);
+
+ /// Get the PC address of the instruction which executes after the call
+ /// returns. Returns LLDB_INVALID_ADDRESS iff this is a tail call.
+ lldb::addr_t GetReturnPCAddress() const;
+
+private:
+ void ParseSymbolFileAndResolve(ModuleList &images);
+
+ /// Whether or not an attempt was made to find the callee's definition.
+ bool resolved;
+
+ /// Either the callee's mangled name or its definition, discriminated by
+ /// \ref resolved.
+ union {
+ const char *mangled_name;
+ Function *def;
+ } lazy_callee;
+
+ /// An invalid address if this is a tail call. Otherwise, the return PC.
+ lldb::addr_t return_pc;
+
+ DISALLOW_COPY_AND_ASSIGN(CallEdge);
+};
+
//----------------------------------------------------------------------
/// @class Function Function.h "lldb/Symbol/Function.h"
/// A class that describes a function.
@@ -396,6 +440,20 @@
//------------------------------------------------------------------
void GetEndLineSourceInfo(FileSpec &source_file, uint32_t &line_no);
+ //------------------------------------------------------------------
+ /// Get the outgoing call edges from this function, sorted by their return
+ /// PC addresses (in increasing order).
+ ///
+ /// @return A mutable array reference with the same lifetime as `this`.
+ //------------------------------------------------------------------
+ llvm::MutableArrayRef<CallEdge> GetCallEdges();
+
+ //------------------------------------------------------------------
+ /// Get the outgoing tail-callling edges from this function. If none exist,
+ /// return None.
+ //------------------------------------------------------------------
+ llvm::MutableArrayRef<CallEdge> GetTailCallingEdges();
+
//------------------------------------------------------------------
/// Get accessor for the block list.
///
@@ -587,6 +645,10 @@
Flags m_flags;
uint32_t
m_prologue_byte_size; ///< Compute the prologue size once and cache it
+
+ bool m_call_edges_resolved = false; ///< Whether call site info has been
+ /// parsed.
+ std::vector<CallEdge> m_call_edges; ///< Outgoing call edges.
private:
DISALLOW_COPY_AND_ASSIGN(Function);
};
Index: lldb/include/lldb/Symbol/Block.h
===================================================================
--- lldb/include/lldb/Symbol/Block.h
+++ lldb/include/lldb/Symbol/Block.h
@@ -327,6 +327,14 @@
return m_inlineInfoSP.get();
}
+ //------------------------------------------------------------------
+ /// Get the symbol file which contains debug info for this block's
+ /// symbol context module.
+ ///
+ /// @return A pointer to the symbol file or nullptr.
+ //------------------------------------------------------------------
+ SymbolFile *GetSymbolFile();
+
CompilerDeclContext GetDeclContext();
//------------------------------------------------------------------
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