VS2017 blocking on non-existing object files when debugging with pdb file

Question

We are in the process of switching Visual C++ projects to the vc141 toolchain (VS 2017). We have encountered a problem where Visual Studio is unable to use a .pdb file whose source .obj files don't exist anymore (for example because they have been compiled on a build server).

Let's take a very simple executable project:

#include <iostream>

int main() {
    std::cout << "Hello world\n";
    std::cin.ignore();
}

The .vcxproj file is all default, except for <GenerateDebugInformation>true</GenerateDebugInformation> to generate the pdb file.

Reproduction steps are, always using VS2017:

• Compiling the project
• Placing a breakpoint inside main
• Removing the intermediate Debug/ directory containing the .obj files
• Disabling build-on-run through the configuration manager (so it won't recreate them)
• Starting a debug session

This works fine with the vc100 (VS 2010) toolchain, and the breakpoint works, but it immediately triggers the following error with vc141:

Error: Unable to open file
<path>\Debug\main.obj. Error code = 0x80070003.

This very generic error code corresponds indeed to FACILITY_WIN32/ERROR_PATH_NOT_FOUND. The path to main.obj can be found inside both versions of the .pdb file, thus it is unclear to us why VS suddenly breaks down when it doesn't find it.

The "Modules" view shows that the .pdb file seems to be loaded correctly. Additionally, the breakpoint's tooltip shows the following error:

The breakpoint will not currently be hit. Unexpected symbol reader error while processing MyUser_141.exe.

What could be a solution or a workaround for this problem, given that we cannot debug on the machine that compiles the binaries in our real-case application?

Here is the full .vcxproj file:

<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <ItemGroup Label="ProjectConfigurations">
    <ProjectConfiguration Include="Debug|Win32">
      <Configuration>Debug</Configuration>
      <Platform>Win32</Platform>
    </ProjectConfiguration>
  </ItemGroup>
  <PropertyGroup Label="Globals">
    <VCProjectVersion>15.0</VCProjectVersion>
    <RootNamespace>MyUser_141</RootNamespace>
    <WindowsTargetPlatformVersion>10.0.17134.0</WindowsTargetPlatformVersion>
    <ProjectGuid>{90982029-29B8-4C9B-AFB7-B8F555F15C1E}</ProjectGuid>
  </PropertyGroup>
  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
    <ConfigurationType>Application</ConfigurationType>
    <UseDebugLibraries>true</UseDebugLibraries>
    <PlatformToolset>v141</PlatformToolset>
    <CharacterSet>MultiByte</CharacterSet>
  </PropertyGroup>
  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
  <ImportGroup Label="ExtensionSettings">
  </ImportGroup>
  <ImportGroup Label="Shared">
  </ImportGroup>
  <ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
  </ImportGroup>
  <PropertyGroup Label="UserMacros" />
  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
    <Link>
      <GenerateDebugInformation>true</GenerateDebugInformation>
    </Link>
  </ItemDefinitionGroup>
  <ItemGroup>
    <ClCompile Include="main.cpp" />
  </ItemGroup>
  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
  <ImportGroup Label="ExtensionTargets">
  </ImportGroup>
</Project>

---

Further research:

• We tried some other toolchain versions. The bug is not present in v14.0 (VS 2015), but is present as soon as 14.11 (VS2017 15.3).

• Using v141_xp, which as far as we can tell uses the same toolchain but older system libraries, works.

Answer 1

To fix this, make the following change in the property pages of the project(s) that build your executable(s) and DLL(s):

Configuration Properties -> Linker -> Debugging -> Generate Debug Info -> Generate Debug Information optimized for sharing and publishing

Static libraries, having no link step, don't need this. .EXEs and DLLs do.

Answer 2

When you specify /DEBUG with no additional options, the linker defaults to /DEBUG:FULL for command line and makefile builds, for release builds in the Visual Studio IDE, and for both debug and release builds in Visual Studio 2015 and earlier versions. Beginning in Visual Studio 2017, the build system in the IDE defaults to /DEBUG:FASTLINK when you specify the /DEBUG option for debug builds. Other defaults are unchanged to maintain backward compatibility. Source : https://developercommunity.visualstudio.com/content/problem/259283/error-unable-to-open-file-mainobj-error-code-0x800.html