import-trace: record stats on failed register mappings

The import-trace tool now systematically collects statistics on which
LLVM -> FAIL* register ID mappings failed during import, and presents
those after the import finished.

Change-Id: Ied67853d754483277868fe21bf2c6efeaeb60f09

src/core/util/llvmdisassembler/LLVMDisassembler.cpp

@@ -15,8 +15,6 @@ static std::ostream& operator<<(std::ostream& stream, const llvm::StringRef& s)
 
 LLVMtoFailTranslator *LLVMDisassembler::getTranslator() {
 	if (ltofail == 0) {
-		std::cout << "ArchType: " << llvm::Triple::getArchTypeName(	 llvm::Triple::ArchType(object->getArch())	) << std::endl;
-
 		switch ( llvm::Triple::ArchType(object->getArch()) ) {
 		case llvm::Triple::x86:
 		case llvm::Triple::x86_64:
@@ -26,7 +24,9 @@ LLVMtoFailTranslator *LLVMDisassembler::getTranslator() {
 			ltofail = new LLVMtoFailGem5(this);
 			break;
 		default:
-			std::cout << " not supported :(";
+			std::cerr << "ArchType "
+				<< llvm::Triple::getArchTypeName(llvm::Triple::ArchType(object->getArch()))
+				<< " not supported\n";
 			exit(1);
 		}
 	}

tools/import-trace/RegisterImporter.cc

@@ -182,9 +182,9 @@ bool RegisterImporter::handle_ip_event(fail::simtime_t curtime, instruction_coun
 		 it != opcode.reg_uses.end(); ++it) {
 		const LLVMtoFailTranslator::reginfo_t &info = m_ltof->getFailRegisterInfo(*it);
 		if (&info == &m_ltof->notfound) {
-			LOG << "Could not find a mapping for LLVM input register #" << std::dec << *it
+			// record failed translation, report later
-			    << " at IP " << std::hex << ev.ip()
+			m_regnotfound[*it].count++;
-			    << ", skipping" << std::endl;
+			m_regnotfound[*it].address.insert(ev.ip());
 			continue;
 		}
 
@@ -202,9 +202,9 @@ bool RegisterImporter::handle_ip_event(fail::simtime_t curtime, instruction_coun
 		 it != opcode.reg_defs.end(); ++it) {
 		const LLVMtoFailTranslator::reginfo_t &info = m_ltof->getFailRegisterInfo(*it);
 		if (&info == &m_ltof->notfound) {
-			LOG << "Could not find a mapping for LLVM output register #" << std::dec << *it
+			// record failed translation, report later
-			    << " at IP " << std::hex << ev.ip()
+			m_regnotfound[*it].count++;
-			    << ", skipping" << std::endl;
+			m_regnotfound[*it].address.insert(ev.ip());
 			continue;
 		}
 
@@ -219,3 +219,30 @@ bool RegisterImporter::handle_ip_event(fail::simtime_t curtime, instruction_coun
 
 	return true;
 }
+
+bool RegisterImporter::trace_end_reached()
+{
+	// report failed LLVM -> FAIL* register mappings, if any
+	if (m_regnotfound.empty()) {
+		return true;
+	}
+
+	LOG << "WARNING: Some LLVM -> FAIL* register mappings failed during import, these will not be injected into:" << std::endl;
+	for (auto it = m_regnotfound.cbegin(); it != m_regnotfound.cend(); ++it) {
+		const LLVMDisassembler::register_t id = it->first;
+		const RegNotFound& rnf = it->second;
+		LOG << "LLVM register " << std::dec << id
+			<< " \"" << disas->getRegisterInfo().getName(id) << "\": "
+			<< "seen " << rnf.count << " times in the trace" << std::endl;
+		std::ostream& o = LOG << "   corresponding instruction addresses in ELF binary: " << std::hex;
+		for (auto addr_it = rnf.address.cbegin(); addr_it != rnf.address.cend(); ++addr_it) {
+			if (addr_it != rnf.address.cbegin()) {
+				o << ", ";
+			}
+			o << "0x" << *addr_it;
+		}
+		o << std::endl;
+	}
+
+	return true;
+}

tools/import-trace/RegisterImporter.hpp

@@ -24,6 +24,15 @@ class RegisterImporter : public Importer {
 	std::set<unsigned> m_register_ids;
 	unsigned m_ip_register_id;
 
+	// Data structures for recording failed LLVM -> FAIL* register mappings,
+	// including occurrence counts in the trace (to give an estimate on the
+	// impact) and instruction addresses (for debugging purposes).
+	struct RegNotFound {
+		uint64_t count = 0;
+		std::set<fail::guest_address_t> address;
+	};
+	std::map<fail::LLVMDisassembler::register_t, RegNotFound> m_regnotfound;
+
 public:
 	RegisterImporter() : Importer(), do_gp(true), do_flags(false), do_ip(false),
 						 do_split_registers(true), m_ip_register_id(0) {}
@@ -42,6 +51,8 @@ protected:
 		return true;
 	}
 
+	virtual bool trace_end_reached();
+
 	virtual void open_unused_ec_intervals() {
 		/* empty, Memory Map has a different meaning in this importer */
 	}