Enable -C jump-tables=no support in gcc codegen backend

Author: pmur

compiler/rustc_codegen_gcc/src/base.rs

@@ -126,6 +126,11 @@ pub fn compile_codegen_unit(
         for arg in &tcx.sess.opts.cg.llvm_args {
             context.add_command_line_option(arg);
         }
+
+        if !tcx.sess.opts.cg.jump_tables {
+            context.add_command_line_option("-fno-jump-tables");
+        }
+
         // NOTE: This is needed to compile the file src/intrinsic/archs.rs during a bootstrap of rustc.
         context.add_command_line_option("-fno-var-tracking-assignments");
         // NOTE: an optimization (https://github.com/rust-lang/rustc_codegen_gcc/issues/53).

src/doc/rustc/src/codegen-options/index.md

@@ -211,8 +211,8 @@ with coverage tools other than those built and shipped with the compiler.
 
 ## jump-tables
 
-This option is used to allow or prevent the LLVM codegen backend from creating
-jump tables when lowering switches.
+This option is used to allow or prevent the LLVM or GCC codegen backend from
+creating jump tables when lowering switches.
 
 * `y`, `yes`, `on`, `true` or no value: allow jump tables (the default).
 * `n`, `no`, `off` or `false`: disable jump tables.