Bug#831809: g++-5: exceptions thrown from callback with va_list not caugth on at least armhf and powerpc

[Gert Wollny]

Package: g++-5
Version: 5.4.0-6
Severity: important
Tags: upstream

Dear Maintainer,

in the attached program the exception is not caught on armhf and powerpc.

The compilation command line is

  g++ test_tiff_throw.cc -o test-tiff-throw -ltiff

I've tested the compilers:

powerpc:

  g++ (Debian 5.4.0-6) 5.4.0 20160609
  g++-6 (Debian 6.1.1-9) 6.1.1 20160705

armhf:
  g++ (Ubuntu/Linaro 5.3.1-14ubuntu2.1) 5.3.1 20160413

and optimization levels -O0, -O1, and -O2.

In each case the program aborts with

   terminate called after throwing an instance of 'std::runtime_error'
     what():  should_not_exists.tif: No such file or directory
   Aborted

The code works as expected on amd64 with:

  g++ (Debian 5.4.0-6) 5.4.0 20160609
  g++ (Gentoo 5.4.0 p1.0, pie-0.6.5) 5.4.0

and i386:
  g++ (Debian 5.4.0-6) 5.4.0 20160609

In this case the program prints:

  "error: should_not_exists.tif: No such file or directory"

I was not able to create a simpler test case. Specifically:

Normally throw-catch works fine, i.e. the exception is caught even when using a
callback funtion that makes use of the va_list based constructs, but everything
resides in the same translation unit. The only way I can get this error
reproducible is by using libtiff that internally uses the va_* constructs to
forwards the error function to the user supplied function.

Tested libtiff5-dev:
   4.0.6-2 (powerpc, amd64)
   4.0.6-1 (armhf, i386)

Best regards,
Gert










-- System Information:
Debian Release: stretch/sid
  APT prefers unstable-debug
  APT policy: (500, 'unstable-debug'), (500, 'unstable'), (500, 'testing'), (1, 
'experimental')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.6.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages g++-5 depends on:
ii  gcc-5            5.4.0-6
ii  gcc-5-base       5.4.0-6
ii  libc6            2.23-1
ii  libgmp10         2:6.1.1+dfsg-1
ii  libisl15         0.17.1-1
ii  libmpc3          1.0.3-1
ii  libmpfr4         3.1.4-2
ii  libstdc++-5-dev  5.4.0-6
ii  zlib1g           1:1.2.8.dfsg-2+b1

g++-5 recommends no packages.

Versions of packages g++-5 suggests:
pn  g++-5-multilib    <none>
pn  gcc-5-doc         <none>
pn  libstdc++6-5-dbg  <none>

-- no debconf information

#include <tiffio.h>
#include <exception>
#include <iostream>

typedef TIFF * PTIFF;
void MyErrorHandler(const char *module, const char *fmt,  va_list ap)
{
	char buf[16384];

	vsnprintf(buf,16384, fmt, ap);
	throw std::runtime_error(buf);
}

struct CErrorHandlerReplacer {
	CErrorHandlerReplacer():
		m_old_handler(TIFFSetErrorHandler(MyErrorHandler))
	{
	}
	~CErrorHandlerReplacer() {
		TIFFSetErrorHandler(m_old_handler);
	}
private:
	TIFFErrorHandler m_old_handler;
};


struct CTiffFile {
	CTiffFile(const char *name, const char *flags):
		handle(TIFFOpen(name, flags))
	{
	}

	~CTiffFile()
	{
		if (handle)
			TIFFClose(handle);
	}
	operator PTIFF() {
		return handle;
	}
private:
	TIFF *handle;
};

int main(int argc, char **args)
{
	CErrorHandlerReplacer error_replace;

	try {
		CTiffFile tif("should_not_exists.tif", "r");
		if (tif) {
			std::cerr << "File 'should_not_exists.tif' existed\n"; 
		}
		
	}catch (const std::runtime_error& x) {
		std::cerr << "error: " << x.what() << "\n"; 
	}

	return 0; 
}