Raise UndefRefError using SegFault handler

JuliaLang · Dec 3, 2015 · eafd435 · eafd435
1 parent 64e5907
commit eafd435
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Showing 7 changed files with 50 additions and 9 deletions.
diff --git a/src/ccall.cpp b/src/ccall.cpp
@@ -1269,7 +1269,9 @@ static jl_cgval_t emit_ccall(jl_value_t **args, size_t nargs, jl_codectx_t *ctx)
     FunctionType *functype = FunctionType::get(sret ? T_void : prt, fargt_sig, isVa);
 
     if (jl_ptr != NULL) {
-        null_pointer_check(jl_ptr,ctx);
+        // null_pointer_check(jl_ptr, ctx);
+        // We throw a UndefRefError in the SegFault handler if the pointer is
+        // NULL.
         Type *funcptype = PointerType::get(functype,0);
         llvmf = builder.CreateIntToPtr(jl_ptr, funcptype);
     }

diff --git a/src/cgutils.cpp b/src/cgutils.cpp
@@ -1061,11 +1061,16 @@ static void raise_exception_unless(Value *cond, Value *exc, jl_codectx_t *ctx)
     BasicBlock *passBB = BasicBlock::Create(getGlobalContext(),"pass");
     builder.CreateCondBr(cond, passBB, failBB);
     builder.SetInsertPoint(failBB);
+    if (exc) {
 #ifdef LLVM37
-    builder.CreateCall(prepare_call(jlthrow_func), { exc });
+        builder.CreateCall(prepare_call(jlthrow_func), { exc });
 #else
-    builder.CreateCall(prepare_call(jlthrow_func), exc);
+        builder.CreateCall(prepare_call(jlthrow_func), exc);
 #endif
+    }
+    else {
+        builder.CreateLoad(Constant::getNullValue(T_ppint8), true);
+    }
     builder.CreateUnreachable();
     ctx->f->getBasicBlockList().push_back(passBB);
     builder.SetInsertPoint(passBB);
@@ -1090,8 +1095,8 @@ static void raise_exception_if(Value *cond, GlobalVariable *exc, jl_codectx_t *c
 
 static void null_pointer_check(Value *v, jl_codectx_t *ctx)
 {
-    raise_exception_unless(builder.CreateICmpNE(v,Constant::getNullValue(v->getType())),
-                           prepare_global(jlundeferr_var), ctx);
+    raise_exception_unless(builder.CreateICmpNE(v, Constant::getNullValue(v->getType())),
+                           (Value*)NULL, ctx);
 }
 
 static Value *boxed(const jl_cgval_t &v, jl_codectx_t *ctx, jl_value_t *jt=NULL);
@@ -1465,7 +1470,7 @@ static jl_cgval_t emit_getfield_knownidx(const jl_cgval_t &strct, unsigned idx,
     Type *elty = julia_type_to_llvm(jfty);
     assert(elty != NULL);
     if (jfty == jl_bottom_type) {
-        raise_exception_unless(ConstantInt::get(T_int1,0), prepare_global(jlundeferr_var), ctx);
+        raise_exception_unless(ConstantInt::get(T_int1,0), (Value*)NULL, ctx);
         return jl_cgval_t(); // unreachable
     }
     if (type_is_ghost(elty))

diff --git a/src/codegen.cpp b/src/codegen.cpp
@@ -448,7 +448,6 @@ static GlobalVariable *jlemptytuple_var;
 static GlobalVariable *jlfloattemp_var;
 #endif
 static GlobalVariable *jldiverr_var;
-static GlobalVariable *jlundeferr_var;
 static GlobalVariable *jldomerr_var;
 static GlobalVariable *jlovferr_var;
 static GlobalVariable *jlinexacterr_var;
@@ -5626,8 +5625,6 @@ static void init_julia_llvm_env(Module *m)
     jlemptytuple_var = global_to_llvm("jl_emptytuple", (void*)&jl_emptytuple, m);
     jldiverr_var = global_to_llvm("jl_diverror_exception",
                                   (void*)&jl_diverror_exception, m);
-    jlundeferr_var = global_to_llvm("jl_undefref_exception",
-                                    (void*)&jl_undefref_exception, m);
     jldomerr_var = global_to_llvm("jl_domain_exception",
                                   (void*)&jl_domain_exception, m);
     jlovferr_var = global_to_llvm("jl_overflow_exception",

diff --git a/src/signals-mach.c b/src/signals-mach.c
@@ -120,6 +120,10 @@ kern_return_t catch_exception_raise(mach_port_t            exception_port,
     kern_return_t ret = thread_get_state(thread, x86_EXCEPTION_STATE64, (thread_state_t)&exc_state, &exc_count);
     HANDLE_MACH_ERROR("thread_get_state", ret);
     uint64_t fault_addr = exc_state.__faultvaddr;
+    if (!fault_addr) {
+        jl_throw_in_thread(0, thread, jl_undefref_exception);
+        return KERN_SUCCESS;
+    }
 #ifdef SEGV_EXCEPTION
     if (1) {
 #else

diff --git a/src/signals-unix.c b/src/signals-unix.c
@@ -88,6 +88,12 @@ static void segv_handler(int sig, siginfo_t *info, void *context)
         sigprocmask(SIG_UNBLOCK, &sset, NULL);
         jl_throw(jl_readonlymemory_exception);
     }
+    else if (!info->si_addr) {
+        sigemptyset(&sset);
+        sigaddset(&sset, SIGSEGV);
+        sigprocmask(SIG_UNBLOCK, &sset, NULL);
+        jl_throw(jl_undefref_exception);
+    }
     else {
 #ifdef SEGV_EXCEPTION
         sigemptyset(&sset);

diff --git a/src/signals-win.c b/src/signals-win.c
@@ -173,6 +173,11 @@ static LONG WINAPI _exception_handler(struct _EXCEPTION_POINTERS *ExceptionInfo,
                     jl_throw_in_ctx(jl_readonlymemory_exception, ExceptionInfo->ContextRecord,in_ctx);
                     return EXCEPTION_CONTINUE_EXECUTION;
                 }
+                else if (!ExceptionInfo->ExceptionRecord->ExceptionInformation[1]) {
+                    jl_throw_in_ctx(jl_undefref_exception,
+                                    ExceptionInfo->ContextRecord, in_ctx);
+                    return EXCEPTION_CONTINUE_EXECUTION;
+                }
         }
         jl_safe_printf("\nPlease submit a bug report with steps to reproduce this fault, and any error messages that follow (in their entirety). Thanks.\nException: ");
         switch (ExceptionInfo->ExceptionRecord->ExceptionCode) {

diff --git a/test/core.jl b/test/core.jl
@@ -3503,3 +3503,25 @@ let
     finalize(obj)
     @test finalized == 1
 end
+
+module TestUndefRefErrors14147
+
+using Base.Test
+
+# Test different kinds of UndefRefError
+call_fptr(p) = ccall(p, Int, ())
+return_int_function() = 100
+@test call_fptr(cfunction(return_int_function, Int, Tuple{})) == 100
+@test_throws UndefRefError call_fptr(C_NULL)
+
+type TypeWithUndefField
+    a
+    TypeWithUndefField() = new()
+end
+copy_undef_field(a, b) = (a.a = b.a)
+get_undef_field(a) = a.a
+@test_throws UndefRefError copy_undef_field(TypeWithUndefField(),
+                                            TypeWithUndefField())
+@test_throws UndefRefError get_undef_field(TypeWithUndefField())
+
+end