Generate more stack maps during native debugging.
Generate extra stack map at the start of each java statement.
The stack maps are later translated to DWARF which allows
LLDB to set breakpoints and view local variables.
Change-Id: If00ab875513308e4a1399d1e12e0fe8934a6f0c3
diff --git a/compiler/optimizing/builder.cc b/compiler/optimizing/builder.cc
index 1178d0f..4dd0d26 100644
--- a/compiler/optimizing/builder.cc
+++ b/compiler/optimizing/builder.cc
@@ -17,6 +17,8 @@
#include "builder.h"
#include "art_field-inl.h"
+#include "base/arena_bit_vector.h"
+#include "base/bit_vector-inl.h"
#include "base/logging.h"
#include "class_linker.h"
#include "dex/verified_method.h"
@@ -458,6 +460,19 @@
return false;
}
+ // Find locations where we want to generate extra stackmaps for native debugging.
+ // This allows us to generate the info only at interesting points (for example,
+ // at start of java statement) rather than before every dex instruction.
+ const bool native_debuggable = compiler_driver_ != nullptr &&
+ compiler_driver_->GetCompilerOptions().GetNativeDebuggable();
+ ArenaBitVector* native_debug_info_locations;
+ if (native_debuggable) {
+ const uint32_t num_instructions = code_item.insns_size_in_code_units_;
+ native_debug_info_locations = new (arena_) ArenaBitVector (arena_, num_instructions, false);
+ native_debug_info_locations->ClearAllBits();
+ FindNativeDebugInfoLocations(code_item, native_debug_info_locations);
+ }
+
CreateBlocksForTryCatch(code_item);
InitializeParameters(code_item.ins_size_);
@@ -467,6 +482,11 @@
// Update the current block if dex_pc starts a new block.
MaybeUpdateCurrentBlock(dex_pc);
const Instruction& instruction = *Instruction::At(code_ptr);
+ if (native_debuggable && native_debug_info_locations->IsBitSet(dex_pc)) {
+ if (current_block_ != nullptr) {
+ current_block_->AddInstruction(new (arena_) HNativeDebugInfo(dex_pc));
+ }
+ }
if (!AnalyzeDexInstruction(instruction, dex_pc)) {
return false;
}
@@ -507,6 +527,47 @@
current_block_ = block;
}
+void HGraphBuilder::FindNativeDebugInfoLocations(const DexFile::CodeItem& code_item,
+ ArenaBitVector* locations) {
+ // The callback gets called when the line number changes.
+ // In other words, it marks the start of new java statement.
+ struct Callback {
+ static bool Position(void* ctx, const DexFile::PositionInfo& entry) {
+ static_cast<ArenaBitVector*>(ctx)->SetBit(entry.address_);
+ return false;
+ }
+ };
+ dex_file_->DecodeDebugPositionInfo(&code_item, Callback::Position, locations);
+ // Add native debug info at the start of every basic block.
+ for (uint32_t pc = 0; pc < code_item.insns_size_in_code_units_; pc++) {
+ if (FindBlockStartingAt(pc) != nullptr) {
+ locations->SetBit(pc);
+ }
+ }
+ // Instruction-specific tweaks.
+ const Instruction* const begin = Instruction::At(code_item.insns_);
+ const Instruction* const end = begin->RelativeAt(code_item.insns_size_in_code_units_);
+ for (const Instruction* inst = begin; inst < end; inst = inst->Next()) {
+ switch (inst->Opcode()) {
+ case Instruction::MOVE_EXCEPTION:
+ case Instruction::MOVE_RESULT:
+ case Instruction::MOVE_RESULT_WIDE:
+ case Instruction::MOVE_RESULT_OBJECT: {
+ // The compiler checks that there are no instructions before those.
+ // So generate HNativeDebugInfo after them instead.
+ locations->ClearBit(inst->GetDexPc(code_item.insns_));
+ const Instruction* next = inst->Next();
+ if (next < end) {
+ locations->SetBit(next->GetDexPc(code_item.insns_));
+ }
+ break;
+ }
+ default:
+ break;
+ }
+ }
+}
+
bool HGraphBuilder::ComputeBranchTargets(const uint16_t* code_ptr,
const uint16_t* code_end,
size_t* number_of_branches) {