Move unbox tramp method address table to data segment, MONO_ARCH_CODE…

…_EXEC_ONLY. (dotnet#33969) unbox tramp method addresses are emitted as a table of calls and read at runtime by get_call_table_entry. This is problematic on platforms that doesn't allow data to be read from instruction stream. Fix follow same pattern as method address table emitted as function pointers into table in data segment when using MONO_ARCH_CODE_EXEC_ONLY. Co-authored-by: lateralusX <[email protected]>
Si1ver · Mar 24, 2020 · b159b37 · b159b37
1 parent c67efd8
commit b159b37
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Showing 2 changed files with 17 additions and 5 deletions.
diff --git a/src/mono/mono/mini/aot-compiler.c b/src/mono/mono/mini/aot-compiler.c
@@ -10318,7 +10318,12 @@ emit_code (MonoAotCompile *acfg)
 
 	/* Emit a separate table with the trampoline addresses/offsets */
 	sprintf (symbol, "unbox_trampoline_addresses");
-	emit_section_change (acfg, ".text", 0);
+	if (acfg->flags & MONO_AOT_FILE_FLAG_CODE_EXEC_ONLY) {
+		/* Emit the unbox trampoline address table as a table of pointers */
+		emit_section_change (acfg, ".data", 0);
+	} else {
+		emit_section_change (acfg, ".text", 0);
+	}
 	emit_alignment_code (acfg, 8);
 	emit_info_symbol (acfg, symbol, TRUE);
 
@@ -10335,12 +10340,15 @@ emit_code (MonoAotCompile *acfg)
 
 		if (mono_aot_mode_is_full (&acfg->aot_opts) && m_class_is_valuetype (cfg->orig_method->klass)) {
 #ifdef MONO_ARCH_AOT_SUPPORTED
-			int call_size;
-
 			const int index = get_method_index (acfg, method);
 			sprintf (symbol, "ut_%d", index);
 
-			arch_emit_direct_call (acfg, symbol, FALSE, acfg->thumb_mixed && cfg->compile_llvm, NULL, &call_size);
+			if (acfg->flags & MONO_AOT_FILE_FLAG_CODE_EXEC_ONLY) {
+				emit_pointer (acfg, symbol);
+			} else {
+				int call_size;
+				arch_emit_direct_call (acfg, symbol, FALSE, acfg->thumb_mixed && cfg->compile_llvm, NULL, &call_size);
+			}
 #endif
 		}
 	}

diff --git a/src/mono/mono/mini/aot-runtime.c b/src/mono/mono/mini/aot-runtime.c
@@ -6077,7 +6077,11 @@ mono_aot_get_unbox_trampoline (MonoMethod *method, gpointer addr)
 		}
 	}
 
-	code = get_call_table_entry (amodule->unbox_trampoline_addresses, entry_index, amodule->info.call_table_entry_size);
+	if (amodule->info.flags & MONO_AOT_FILE_FLAG_CODE_EXEC_ONLY)
+		code = ((gpointer*)amodule->unbox_trampoline_addresses) [entry_index];
+	else
+		code = get_call_table_entry (amodule->unbox_trampoline_addresses, entry_index, amodule->info.call_table_entry_size);
+
 	g_assert (code);
 
 	tinfo = mono_tramp_info_create (NULL, (guint8 *)code, 0, NULL, NULL);