transpile: assembly: use () rather than [] for indirect operands with AT&T syntax

Author: fw-immunant

c2rust-transpile/src/translator/assembly.rs

@@ -559,6 +559,7 @@ fn tied_output_operand_idx(
 /// {0:y} (and wrapping mem-only references in square brackets).
 fn rewrite_asm<F: Fn(&str) -> bool, M: Fn(usize) -> usize>(
     asm: &str,
+    att_syntax: bool,
     input_op_mapper: M,
     is_mem_only: F,
     arch: Arch,
@@ -647,7 +648,10 @@ fn rewrite_asm<F: Fn(&str) -> bool, M: Fn(usize) -> usize>(
             }
             let mem_only = is_mem_only(index_str);
             // Push the reference wrapped in {}, or in [{}] if mem-only
-            out.push_str(if mem_only { "[{" } else { "{" });
+            if mem_only {
+                out.push(if att_syntax { '(' } else { '[' });
+            };
+            out.push('{');
             let idx: usize = index_str
                 .parse()
                 .map_err(|_| TranslationError::generic("could not parse operand idx"))?;
@@ -656,7 +660,10 @@ fn rewrite_asm<F: Fn(&str) -> bool, M: Fn(usize) -> usize>(
                 out.push(':');
                 out.push_str(&new_modifiers);
             }
-            out.push_str(if mem_only { "}]" } else { "}" });
+            out.push('}');
+            if mem_only {
+                out.push(if att_syntax { ')' } else { ']' });
+            };
             // Push the rest of the chunk
             out.push_str(&chunk[end_idx..]);
             continue;
@@ -832,6 +839,7 @@ impl<'c> Translation<'c> {
         // Rewrite arg references in assembly template
         let rewritten_asm = rewrite_asm(
             asm,
+            att_syntax,
             |idx: usize| {
                 new_idx_for_orig(tied_output_operand_idx(idx, outputs.len(), &tied_operands))
             },

c2rust-transpile/tests/snapshots/snapshots__transpile-x86_64@vm_x86.c.snap

@@ -58,7 +58,7 @@ pub unsafe extern "C" fn VM_CallCompiled(
     *opStack = 0 as core::ffi::c_int;
     opStackOfs = 0 as core::ffi::c_int;
     asm!(
-        "movq [{2}], %rax\n", "movq [{0}], %r8\n", "movq [{1}], %r9\n", "push %r15\n",
+        "movq ({2}), %rax\n", "movq ({0}), %r8\n", "movq ({1}), %r9\n", "push %r15\n",
         "push %r14\n", "push %r13\n", "push %r12\n", "callq *%rax\n", "pop %r12\n",
         "pop %r13\n", "pop %r14\n", "pop %r15\n", "\n", "mov {restmp0:x}, %bx\n", in
         (reg) & (* vm).instructionPointers, in (reg) & (* vm).dataBase, in (reg) &