patches/exceptions.diff

Make GMP compile in a noexcept environment

GMP throws exceptions to indicate errors like failed allocation or negative
factorials. Change these to print a terse error message and SIGABRT.

Ideally, these would `LOG(FATAL)`. However, giving GMP an Abseil dependency
breaks Haskell binaries. (The problematic dependency chain appears to be
Haskell -> GMP -> Abseil -> libunwind.) Instead, just log using `std::cerr` and
call `std::abort`; the abnormal termination will trigger a stack trace in
google3 binaries anyway.

This is an updated version of cl/50915228.

--- a/gmpxx.h
+++ b/gmpxx.h
@@ -39,7 +39,12 @@ see https://www.gnu.org/licenses/.  */
 #include <utility>
 #include <algorithm>  /* swap */
 #include <string>
+#ifdef __EXCEPTIONS
 #include <stdexcept>
+#else
+#include <cstdlib>
+#include <iostream>
+#endif
 #include <cfloat>
 #include <gmp.h>
 
@@ -1240,7 +1245,14 @@ struct __gmp_fac_function
   static void eval(mpz_ptr z, signed long l)
   {
     if (l < 0)
+#ifdef __EXCEPTIONS
       throw std::domain_error ("factorial(negative)");
+#else
+      {
+        std::cerr << "std::domain_error: factorial(negative)\n";
+        std::abort();
+      }
+#endif
     eval(z, static_cast<unsigned long>(l));
   }
   static void eval(mpz_ptr z, mpz_srcptr w)
@@ -1248,9 +1260,23 @@ struct __gmp_fac_function
     if (!mpz_fits_ulong_p(w))
       {
 	if (mpz_sgn(w) < 0)
+#ifdef __EXCEPTIONS
 	  throw std::domain_error ("factorial(negative)");
+#else
+         {
+	    std::cerr << "std::domain_error: factorial(negative)\n";
+           std::abort();
+         }
+#endif
 	else
+#ifdef __EXCEPTIONS
 	  throw std::bad_alloc(); // or std::overflow_error ("factorial")?
+#else
+         {
+	    std::cerr << "std::bad_alloc\n";
+           std::abort();
+         }
+#endif
       }
     eval(z, mpz_get_ui(w));
   }
@@ -1264,7 +1290,14 @@ struct __gmp_primorial_function
   static void eval(mpz_ptr z, signed long l)
   {
     if (l < 0)
+#ifdef __EXCEPTIONS
       throw std::domain_error ("primorial(negative)");
+#else
+      {
+        std::cerr << "std::domain_error: primorial(negative)\n";
+        std::abort();
+      }
+#endif
     eval(z, static_cast<unsigned long>(l));
   }
   static void eval(mpz_ptr z, mpz_srcptr w)
@@ -1272,9 +1305,23 @@ struct __gmp_primorial_function
     if (!mpz_fits_ulong_p(w))
       {
 	if (mpz_sgn(w) < 0)
+#ifdef __EXCEPTIONS
 	  throw std::domain_error ("primorial(negative)");
+#else
+         {
+	    std::cerr << "std::domain_error: primorial(negative)\n";
+           std::abort();
+         }
+#endif
 	else
+#ifdef __EXCEPTIONS
 	  throw std::bad_alloc(); // or std::overflow_error ("primorial")?
+#else
+         {
+	    std::cerr << "std::bad_alloc\n";
+           std::abort();
+         }
+#endif
       }
     eval(z, mpz_get_ui(w));
   }
@@ -1299,7 +1346,14 @@ struct __gmp_fib_function
   static void eval(mpz_ptr z, mpz_srcptr w)
   {
     if (!mpz_fits_slong_p(w))
+#ifdef __EXCEPTIONS
       throw std::bad_alloc(); // or std::overflow_error ("fibonacci")?
+#else
+      {
+        std::cerr << "std::bad_alloc\n";
+        std::abort();
+      }
+#endif
     eval(z, mpz_get_si(w));
   }
   static void eval(mpz_ptr z, double d)
@@ -1650,7 +1704,14 @@ public:
     if (mpz_init_set_str (mp, s, base) != 0)
       {
         mpz_clear (mp);
+#ifdef __EXCEPTIONS
         throw std::invalid_argument ("mpz_set_str");
+#else
+        {
+          std::cerr << "std::invalid_argument: mpz_set_str\n";
+          std::abort();
+        }
+#endif
       }
   }
   explicit __gmp_expr(const std::string &s, int base = 0)
@@ -1658,7 +1719,14 @@ public:
     if (mpz_init_set_str(mp, s.c_str(), base) != 0)
       {
         mpz_clear (mp);
+#ifdef __EXCEPTIONS
         throw std::invalid_argument ("mpz_set_str");
+#else
+        {
+          std::cerr << "std::invalid_argument: mpz_set_str\n";
+          std::abort();
+        }
+#endif
       }
   }
 
@@ -1685,13 +1753,27 @@ public:
   __gmp_expr & operator=(const char *s)
   {
     if (mpz_set_str (mp, s, 0) != 0)
+#ifdef __EXCEPTIONS
       throw std::invalid_argument ("mpz_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpz_set_str\n";
+        std::abort();
+      }
+#endif
     return *this;
   }
   __gmp_expr & operator=(const std::string &s)
   {
     if (mpz_set_str(mp, s.c_str(), 0) != 0)
+#ifdef __EXCEPTIONS
       throw std::invalid_argument ("mpz_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpz_set_str\n";
+        std::abort();
+      }
+#endif
     return *this;
   }
 
@@ -1828,7 +1910,14 @@ public:
     else if (mpq_set_str(mp, s, base) != 0)
       {
         mpq_clear (mp);
+#ifdef __EXCEPTIONS
         throw std::invalid_argument ("mpq_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpq_set_str\n";
+        std::abort();
+      }
+#endif
       }
   }
   explicit __gmp_expr(const std::string &s, int base = 0)
@@ -1837,7 +1926,14 @@ public:
     if (mpq_set_str (mp, s.c_str(), base) != 0)
       {
         mpq_clear (mp);
+#ifdef __EXCEPTIONS
         throw std::invalid_argument ("mpq_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpq_set_str\n";
+        std::abort();
+      }
+#endif
       }
   }
   explicit __gmp_expr(mpq_srcptr q)
@@ -1874,13 +1970,27 @@ public:
   __gmp_expr & operator=(const char *s)
   {
     if (mpq_set_str (mp, s, 0) != 0)
+#ifdef __EXCEPTIONS
       throw std::invalid_argument ("mpq_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpq_set_str\n";
+        std::abort();
+      }
+#endif
     return *this;
   }
   __gmp_expr & operator=(const std::string &s)
   {
     if (mpq_set_str(mp, s.c_str(), 0) != 0)
+#ifdef __EXCEPTIONS
       throw std::invalid_argument ("mpq_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpq_set_str\n";
+        std::abort();
+      }
+#endif
     return *this;
   }
 
@@ -2038,7 +2148,14 @@ public:
     if (mpf_init_set_str (mp, s, 0) != 0)
       {
         mpf_clear (mp);
+#ifdef __EXCEPTIONS
         throw std::invalid_argument ("mpf_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpf_set_str\n";
+        std::abort();
+      }
+#endif
       }
   }
   __gmp_expr(const char *s, mp_bitcnt_t prec, int base = 0)
@@ -2047,7 +2164,14 @@ public:
     if (mpf_set_str(mp, s, base) != 0)
       {
         mpf_clear (mp);
+#ifdef __EXCEPTIONS
         throw std::invalid_argument ("mpf_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpf_set_str\n";
+        std::abort();
+      }
+#endif
       }
   }
   explicit __gmp_expr(const std::string &s)
@@ -2055,7 +2179,14 @@ public:
     if (mpf_init_set_str(mp, s.c_str(), 0) != 0)
       {
         mpf_clear (mp);
+#ifdef __EXCEPTIONS
         throw std::invalid_argument ("mpf_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpf_set_str\n";
+        std::abort();
+      }
+#endif
       }
   }
   __gmp_expr(const std::string &s, mp_bitcnt_t prec, int base = 0)
@@ -2064,7 +2195,14 @@ public:
     if (mpf_set_str(mp, s.c_str(), base) != 0)
       {
         mpf_clear (mp);
+#ifdef __EXCEPTIONS
         throw std::invalid_argument ("mpf_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpf_set_str\n";
+        std::abort();
+      }
+#endif
       }
   }
 
@@ -2093,13 +2231,27 @@ public:
   __gmp_expr & operator=(const char *s)
   {
     if (mpf_set_str (mp, s, 0) != 0)
+#ifdef __EXCEPTIONS
       throw std::invalid_argument ("mpf_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpf_set_str\n";
+        std::abort();
+      }
+#endif
     return *this;
   }
   __gmp_expr & operator=(const std::string &s)
   {
     if (mpf_set_str(mp, s.c_str(), 0) != 0)
+#ifdef __EXCEPTIONS
       throw std::invalid_argument ("mpf_set_str");
+#else
+      {
+        std::cerr << "std::invalid_argument: mpf_set_str\n";
+        std::abort();
+      }
+#endif
     return *this;
   }
 
@@ -3505,7 +3657,14 @@ public:
 		mp_bitcnt_t size)
   {
     if (f (state, size) == 0)
+#ifdef __EXCEPTIONS
       throw std::length_error ("gmp_randinit_lc_2exp_size");
+#else
+      {
+        std::cerr << "std::length_error: gmp_randinit_lc_2exp_size\n";
+        std::abort();
+      }
+#endif
   }
 
   ~gmp_randclass() { gmp_randclear(state); }