[meta] Generate full documentation for instructions in InstBuilder;

cranelift/codegen/meta/src/cdsl/instructions.rs

@@ -97,7 +97,7 @@ pub struct InstructionContent {
     pub opcode_number: OpcodeNumber,
 
     /// Documentation string.
-    doc: String,
+    pub doc: String,
 
     /// Input operands. This can be a mix of SSA value operands and other operand kinds.
     pub operands_in: Vec<Operand>,
@@ -162,16 +162,6 @@ impl Instruction {
         }
     }
 
-    pub fn doc_comment_first_line(&self) -> &str {
-        for line in self.doc.split("\n") {
-            let stripped = line.trim();
-            if stripped.len() > 0 {
-                return stripped;
-            }
-        }
-        ""
-    }
-
     pub fn all_typevars(&self) -> Vec<&TypeVar> {
         match &self.polymorphic_info {
             Some(poly) => {

cranelift/codegen/meta/src/gen_inst.rs

@@ -930,7 +930,7 @@ fn gen_inst_builder(inst: &Instruction, format: &InstructionFormat, fmt: &mut Fo
         rtype
     );
 
-    fmt.doc_comment(format!("`{}`\n\n{}", inst, inst.doc_comment_first_line()));
+    fmt.doc_comment(&inst.doc);
     fmt.line("#[allow(non_snake_case)]");
     fmtln!(fmt, "fn {} {{", proto);
     fmt.indent(|fmt| {