Merge pull request #33820 from JuliaLang/vc/backtrace_ccall

Better stacktraces for `ccall` libraries that do not exist

Author: vchuravy

src/ccall.cpp

@@ -663,22 +663,18 @@ static jl_cgval_t emit_cglobal(jl_codectx_t &ctx, jl_value_t **args, size_t narg
         }
         else {
             void *symaddr;
-            if (!jl_dlsym(jl_get_library(sym.f_lib), sym.f_name, &symaddr, 0)) {
-                std::stringstream msg;
-                msg << "cglobal: could not find symbol ";
-                msg << sym.f_name;
-                if (sym.f_lib != NULL) {
-#ifdef _OS_WINDOWS_
-                    assert(sym.f_lib != JL_EXE_LIBNAME && sym.f_lib != JL_DL_LIBNAME);
-#endif
-                    msg << " in library ";
-                    msg << sym.f_lib;
-                }
-                emit_error(ctx, msg.str());
+
+            void* libsym = jl_get_library_(sym.f_lib, 0);
+            if (!libsym || !jl_dlsym(libsym, sym.f_name, &symaddr, 0)) {
+                // Error mode, either the library or the symbol couldn't be find during compiletime.
+                // Fallback to a runtime symbol lookup.
+                res = runtime_sym_lookup(ctx, cast<PointerType>(T_pint8), sym.f_lib, sym.f_name, ctx.f);
+                res = ctx.builder.CreatePtrToInt(res, lrt);
+            } else {
+                // since we aren't saving this code, there's no sense in
+                // putting anything complicated here: just JIT the address of the cglobal
+                res = ConstantInt::get(lrt, (uint64_t)symaddr);
             }
-            // since we aren't saving this code, there's no sense in
-            // putting anything complicated here: just JIT the address of the cglobal
-            res = ConstantInt::get(lrt, (uint64_t)symaddr);
         }
     }
 
@@ -1877,23 +1873,17 @@ jl_cgval_t function_sig_t::emit_a_ccall(
         }
         else {
             void *symaddr;
-            if (!jl_dlsym(jl_get_library(symarg.f_lib), symarg.f_name, &symaddr, 0)) {
-                std::stringstream msg;
-                msg << "ccall: could not find function ";
-                msg << symarg.f_name;
-                if (symarg.f_lib != NULL) {
-#ifdef _OS_WINDOWS_
-                    assert(symarg.f_lib != JL_EXE_LIBNAME && symarg.f_lib != JL_DL_LIBNAME);
-#endif
-                    msg << " in library ";
-                    msg << symarg.f_lib;
-                }
-                emit_error(ctx, msg.str());
-                return jl_cgval_t();
+
+            void* libsym = jl_get_library_(symarg.f_lib, 0);
+            if (!libsym || !jl_dlsym(libsym, symarg.f_name, &symaddr, 0)) {
+                // either the library or the symbol could not be found, place a runtime
+                // lookup here instead.
+                llvmf = runtime_sym_lookup(ctx, funcptype, symarg.f_lib, symarg.f_name, ctx.f);
+            } else {
+                // since we aren't saving this code, there's no sense in
+                // putting anything complicated here: just JIT the function address
+                llvmf = literal_static_pointer_val(ctx, symaddr, funcptype);
             }
-            // since we aren't saving this code, there's no sense in
-            // putting anything complicated here: just JIT the function address
-            llvmf = literal_static_pointer_val(ctx, symaddr, funcptype);
         }
     }
 

src/julia_internal.h

@@ -861,7 +861,8 @@ extern void *jl_crtdll_handle;
 extern void *jl_winsock_handle;
 #endif
 
-void *jl_get_library(const char *f_lib);
+void *jl_get_library_(const char *f_lib, int throw_err);
+#define jl_get_library(f_lib) jl_get_library_(f_lib, 1)
 JL_DLLEXPORT void *jl_load_and_lookup(const char *f_lib, const char *f_name,
                                       void **hnd);
 JL_DLLEXPORT jl_value_t *jl_get_cfunction_trampoline(

src/runtime_ccall.cpp

@@ -27,7 +27,7 @@ using namespace llvm;
 static std::map<std::string, void*> libMap;
 static jl_mutex_t libmap_lock;
 extern "C"
-void *jl_get_library(const char *f_lib)
+void *jl_get_library_(const char *f_lib, int throw_err)
 {
     void *hnd;
 #ifdef _OS_WINDOWS_
@@ -47,7 +47,7 @@ void *jl_get_library(const char *f_lib)
     if (hnd != NULL)
         return hnd;
     // We might run this concurrently on two threads but it doesn't matter.
-    hnd = jl_load_dynamic_library(f_lib, JL_RTLD_DEFAULT, 1);
+    hnd = jl_load_dynamic_library(f_lib, JL_RTLD_DEFAULT, throw_err);
     if (hnd != NULL)
         jl_atomic_store_release(map_slot, hnd);
     return hnd;

stdlib/InteractiveUtils/test/runtests.jl

@@ -251,12 +251,25 @@ end
 @which get_A18434()(1, y=2)
 @test counter18434 == 2
 
+@eval function f_invalid(x)
+    Base.@_noinline_meta
+    $(Expr(:loopinfo, 1.0f0)) # some expression that throws an error in codegen
+    x
+end
+
+let _true = Ref(true), g, h
+    @noinline g() = _true[] ? 0 : h()
+    @noinline h() = (g(); f_invalid(_true[]))
+    @test_throws ErrorException @code_native h() # due to a failure to compile f()
+    @test g() == 0
+end
+
 let _true = Ref(true), f, g, h
-    @noinline f() = ccall((:time, "error_library_doesnt_exist\0"), Cvoid, ()) # some expression that throws an error in codegen
+    @noinline f() = ccall((:time, "error_library_doesnt_exist\0"), Cvoid, ()) # should throw error during runtime
     @noinline g() = _true[] ? 0 : h()
     @noinline h() = (g(); f())
-    @test_throws ErrorException @code_native h() # due to a failure to compile f()
     @test g() == 0
+    @test_throws ErrorException h()
 end
 
 module ReflectionTest