Introduce GAP_SETJMP and GAP_LONGJMP wrappers

src/common.h

@@ -47,6 +47,22 @@ GAP_STATIC_ASSERT(sizeof(void *) == SIZEOF_VOID_P, "sizeof(void *) is wrong");
 #endif
 
 
+// GAP_SETJMP and GAP_LONGJMP are used for error handling and for GASMAN's
+// register capture. On POSIX systems we use _setjmp/_longjmp, which do not
+// save and restore the signal mask and thus are much faster. On native
+// Windows those names do not exist (mingw's two-argument _setjmp intrinsic
+// is something else entirely), so use plain setjmp/longjmp there.
+// TODO(windows-port): Windows longjmp performs SEH stack unwinding; if that
+// misbehaves across GAP stack frames, switch to mingw's _setjmp(env, NULL).
+// Callers must include <setjmp.h> themselves.
+#ifdef SYS_IS_WINDOWS
+#define GAP_SETJMP(env) setjmp(env)
+#define GAP_LONGJMP(env, val) longjmp(env, val)
+#else
+#define GAP_SETJMP(env) _setjmp(env)
+#define GAP_LONGJMP(env, val) _longjmp(env, val)
+#endif
+
 #ifdef USE_GASMAN
 #define GAP_ENABLE_SAVELOAD
 #endif

src/gasman.c

@@ -2009,7 +2009,7 @@ static UInt CollectBags_Mark(UInt FullBags)
     }
 
     // mark from the stack
-    _setjmp(RegsBags);
+    GAP_SETJMP(RegsBags);
 #if defined(SYS_IS_SPARC)
     SparcStackFuncBags();
 #endif

src/julia_gc.c

@@ -579,7 +579,7 @@ static void GapRootScanner(int full)
     // towards the stack bottom, ensuring that we also scan any
     // references stored in registers.
     jmp_buf registers;
-    _setjmp(registers);
+    GAP_SETJMP(registers);
     TryMarkRange(ptls, registers, (char *)registers + sizeof(jmp_buf));
     TryMarkRange(ptls, (char *)registers + sizeof(jmp_buf), stackend);
 

src/libgap-api.h

@@ -104,7 +104,7 @@ static inline int GAP_Error_Postjmp_(int JumpRet)
 
 #define GAP_Error_Setjmp()                                                   \
     (GAP_unlikely(GAP_Error_Prejmp_(__FILE__, __LINE__)) ||                  \
-     GAP_Error_Postjmp_(_setjmp(*GAP_GetReadJmpError())))
+     GAP_Error_Postjmp_(GAP_SETJMP(*GAP_GetReadJmpError())))
 
 
 // Code which uses the GAP API exposed by this header file should sandwich

src/read.c

@@ -77,7 +77,7 @@
 #define TRY_IF_NO_ERROR                                                      \
     if (!rs->s.NrError) {                                                    \
         volatile Int recursionDepth = GetRecursionDepth();                   \
-        if (_setjmp(STATE(ReadJmpError))) {                                  \
+        if (GAP_SETJMP(STATE(ReadJmpError))) {                               \
             SetRecursionDepth(recursionDepth);                               \
             rs->s.NrError++;                                                 \
         }                                                                    \

src/trycatch.c

@@ -58,5 +58,5 @@ void GAP_THROW(void)
     int depth = STATE(TryCatchDepth);
     for (int i = 0; i < ARRAY_SIZE(throwObservers) && throwObservers[i]; ++i)
         (throwObservers[i])(depth);
-    _longjmp(STATE(ReadJmpError), 1);
+    GAP_LONGJMP(STATE(ReadJmpError), 1);
 }

src/trycatch.h

@@ -87,7 +87,7 @@ void InvokeTryCatchHandler(TryCatchMode mode);
     GAP_TryCatchEnv gap__env;                                                \
     gap_safe_trycatch(&gap__env);                                            \
     InvokeTryCatchHandler(TryEnter);                                         \
-    if (!_setjmp(STATE(ReadJmpError)))                                       \
+    if (!GAP_SETJMP(STATE(ReadJmpError)))                                    \
         for (gap__i = 1; gap__i; gap__i = 0,                                 \
             InvokeTryCatchHandler(TryLeave),                                 \
             gap_restore_trycatch(&gap__env))