src: print more debug info when LLNODE_DEBUG=true

PR-URL: #151
Refs: nodejs/post-mortem#50
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

Author: joyeecheung

Makefile

@@ -1,32 +1,53 @@
+TEST_LLDB_BINARY ?= $(shell which lldb-3.9)
+
+.PHONY: all
 all:
 	@echo "Please take a look at README.md"
 
+.PHONY: install-osx
 install-osx:
 	mkdir -p ~/Library/Application\ Support/LLDB/PlugIns/
 	cp -rf ./out/Release/llnode.dylib \
 		~/Library/Application\ Support/LLDB/PlugIns/
 
+.PHONY: uninstall-osx
 uninstall-osx:
 	rm ~/Library/Application\ Support/LLDB/PlugIns/llnode.dylib
 
+.PHONY: install-linux
 install-linux:
 	mkdir -p /usr/lib/lldb/plugins
 	cp -rf ./out/Release/lib.target/llnode.so /usr/lib/lldb/plugins
 
+.PHONY: uninstall-linux
 uninstall-linux:
 	rm /usr/lib/lldb/plugins/llnode.so
 
+.PHONY: format
 format:
 	clang-format -i src/*
 
-configure: scripts/configure.js
+# This depends on the system setting e.g. $PATH so can't actually be skipped
+.PHONY: configure
+configure:
 	node scripts/configure.js
+	./gyp_llnode
 
+.PHONY: plugin
 plugin: configure
-	./gyp_llnode
 	$(MAKE) -C out/
-
-_travis: plugin
-	TEST_LLDB_BINARY=`which lldb-3.9` TEST_LLNODE_DEBUG=true npm test
-
-.PHONY: all
+	node scripts/cleanup.js
+
+.PHONY: _travis
+_travis:
+	TEST_LLDB_BINARY="$(TEST_LLDB_BINARY)" \
+	TEST_LLNODE_DEBUG=true \
+	LLNODE_DEBUG=true \
+	npm test
+
+.PHONY: clean
+clean:
+	$(RM) -r out
+	$(RM) options.gypi
+	$(RM) lldb
+	$(RM) llnode.so llnode.dylib

package.json

@@ -21,6 +21,7 @@
     "url": "git+ssh://git@github.com/nodejs/llnode.git"
   },
   "files": [
+    "Makefile",
     "llnode.gyp.json",
     "gyp_llnode",
     "common.gypi",

src/llnode.cc

@@ -299,11 +299,24 @@ bool ListCmd::DoExecute(SBDebugger d, char** cmd,
   return true;
 }
 
+
+void InitDebugMode() {
+  bool is_debug_mode = false;
+  char* var = getenv("LLNODE_DEBUG");
+  if (var != nullptr && strlen(var) != 0) {
+    is_debug_mode = true;
+  }
+
+  v8::Error::SetDebugMode(is_debug_mode);
+}
+
 }  // namespace llnode
 
 namespace lldb {
 
 bool PluginInitialize(SBDebugger d) {
+  llnode::InitDebugMode();
+
   SBCommandInterpreter interpreter = d.GetCommandInterpreter();
 
   SBCommand v8 = interpreter.AddMultiwordCommand("v8", "Node.js helpers");

src/llv8-constants.cc

@@ -1,6 +1,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <cinttypes>
 #include <string>
 
 #include <lldb/API/SBExpressionOptions.h>
@@ -23,14 +24,6 @@ using lldb::addr_t;
 
 static std::string kConstantPrefix = "v8dbg_";
 
-static bool IsDebugMode() {
-  char* var = getenv("LLNODE_DEBUG");
-  if (var == nullptr) return false;
-
-  return strlen(var) != 0;
-}
-
-
 void Module::Assign(SBTarget target, Common* common) {
   loaded_ = false;
   target_ = target;
@@ -46,20 +39,20 @@ static int64_t LookupConstant(SBTarget target, const char* name, int64_t def,
 
   SBSymbolContextList context_list = target.FindSymbols(name);
   if (!context_list.IsValid() || context_list.GetSize() == 0) {
-    err = Error::Failure("Failed to find symbol");
+    err = Error::Failure("Failed to find symbol %s", name);
     return res;
   }
 
   SBSymbolContext context = context_list.GetContextAtIndex(0);
   SBSymbol symbol = context.GetSymbol();
   if (!symbol.IsValid()) {
-    err = Error::Failure("Failed to fetch symbol");
+    err = Error::Failure("Failed to fetch symbol %s", name);
     return res;
   }
 
   SBAddress start = symbol.GetStartAddress();
   SBAddress end = symbol.GetEndAddress();
-  size_t size = end.GetOffset() - start.GetOffset();
+  uint32_t size = end.GetOffset() - start.GetOffset();
 
   SBError sberr;
 
@@ -79,12 +72,13 @@ static int64_t LookupConstant(SBTarget target, const char* name, int64_t def,
     int8_t tmp = process.ReadUnsignedFromMemory(addr, size, sberr);
     res = static_cast<int64_t>(tmp);
   } else {
-    err = Error::Failure("Unexpected symbol size");
+    err = Error::Failure("Unexpected symbol size %" PRIu32 " of symbol %s",
+                         size, name);
     return res;
   }
 
   if (sberr.Fail())
-    err = Error::Failure("Failed to load symbol");
+    err = Error::Failure("Failed to load symbol %s", name);
   else
     err = Error::Ok();
 
@@ -95,7 +89,9 @@ static int64_t LookupConstant(SBTarget target, const char* name, int64_t def,
 int64_t Module::LoadRawConstant(const char* name, int64_t def) {
   Error err;
   int64_t v = LookupConstant(target_, name, def, err);
-  if (err.Fail() && IsDebugMode()) fprintf(stderr, "Failed to load %s\n", name);
+  if (err.Fail()) {
+    Error::PrintInDebugMode("Failed to load raw constant %s", name);
+  }
 
   return v;
 }
@@ -105,7 +101,9 @@ int64_t Module::LoadConstant(const char* name, int64_t def) {
   Error err;
   int64_t v =
       LookupConstant(target_, (kConstantPrefix + name).c_str(), def, err);
-  if (err.Fail() && IsDebugMode()) fprintf(stderr, "Failed to load %s\n", name);
+  if (err.Fail()) {
+    Error::PrintInDebugMode("Failed to load constant %s", name);
+  }
 
   return v;
 }
@@ -118,7 +116,10 @@ int64_t Module::LoadConstant(const char* name, const char* fallback,
       LookupConstant(target_, (kConstantPrefix + name).c_str(), def, err);
   if (err.Fail())
     v = LookupConstant(target_, (kConstantPrefix + fallback).c_str(), def, err);
-  if (err.Fail() && IsDebugMode()) fprintf(stderr, "Failed to load %s\n", name);
+  if (err.Fail()) {
+    Error::PrintInDebugMode("Failed to load constant %s, fallback %s", name,
+                            fallback);
+  }
 
   return v;
 }

src/llv8-inl.h

@@ -1,6 +1,7 @@
 #ifndef SRC_LLV8_INL_H_
 #define SRC_LLV8_INL_H_
 
+#include <cinttypes>
 #include "llv8.h"
 
 namespace llnode {
@@ -19,7 +20,9 @@ inline T LLV8::LoadValue(int64_t addr, Error& err) {
 
   T res = T(this, ptr);
   if (!res.Check()) {
-    err = Error::Failure("Invalid value");
+    // TODO(joyeecheung): use Error::Failure() to report information when
+    // there is less noise from here.
+    err = Error(true, "Invalid value");
     return T();
   }
 
@@ -63,7 +66,8 @@ inline T HeapObject::LoadFieldValue(int64_t off, Error& err) {
   T res = v8()->LoadValue<T>(LeaField(off), err);
   if (err.Fail()) return T();
   if (!res.Check()) {
-    err = Error::Failure("Invalid value");
+    err = Error::Failure("Invalid field value %s at 0x%016" PRIx64,
+                         T::ClassName(), off);
     return T();
   }