Rename target_pointer_width to pointer_width and turn it into an u32

Rename target_pointer_width to pointer_width because it is already
member of the Target struct.

The compiler supports only three valid values for target_pointer_width:
16, 32, 64. Thus it can safely be turned into an int.
This means less allocations and clones as well as easier handling of the type.

compiler/rustc_codegen_llvm/src/allocator.rs

@@ -16,10 +16,10 @@ pub(crate) unsafe fn codegen(
 ) {
     let llcx = &*mods.llcx;
     let llmod = mods.llmod();
-    let usize = match &tcx.sess.target.target.target_pointer_width[..] {
-        "16" => llvm::LLVMInt16TypeInContext(llcx),
-        "32" => llvm::LLVMInt32TypeInContext(llcx),
-        "64" => llvm::LLVMInt64TypeInContext(llcx),
+    let usize = match tcx.sess.target.target.pointer_width {
+        16 => llvm::LLVMInt16TypeInContext(llcx),
+        32 => llvm::LLVMInt32TypeInContext(llcx),
+        64 => llvm::LLVMInt64TypeInContext(llcx),
         tws => bug!("Unsupported target word size for int: {}", tws),
     };
     let i8 = llvm::LLVMInt8TypeInContext(llcx);

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -307,7 +307,7 @@ pub struct CodegenContext<B: WriteBackendMethods> {
     pub allocator_module_config: Arc<ModuleConfig>,
     pub tm_factory: TargetMachineFactory<B>,
     pub msvc_imps_needed: bool,
-    pub target_pointer_width: String,
+    pub target_pointer_width: u32,
     pub target_arch: String,
     pub debuginfo: config::DebugInfo,
 
@@ -1022,7 +1022,7 @@ fn start_executing_work<B: ExtraBackendMethods>(
         tm_factory: TargetMachineFactory(backend.target_machine_factory(tcx.sess, ol)),
         total_cgus,
         msvc_imps_needed: msvc_imps_needed(tcx),
-        target_pointer_width: tcx.sess.target.target.target_pointer_width.clone(),
+        target_pointer_width: tcx.sess.target.target.pointer_width,
         target_arch: tcx.sess.target.target.arch.clone(),
         debuginfo: tcx.sess.opts.debuginfo,
     };

compiler/rustc_session/src/config.rs

@@ -742,7 +742,7 @@ pub const fn default_lib_output() -> CrateType {
 pub fn default_configuration(sess: &Session) -> CrateConfig {
     let end = &sess.target.target.target_endian;
     let arch = &sess.target.target.arch;
-    let wordsz = &sess.target.target.target_pointer_width;
+    let wordsz = sess.target.target.pointer_width.to_string();
     let os = &sess.target.target.target_os;
     let env = &sess.target.target.target_env;
     let vendor = &sess.target.target.target_vendor;
@@ -767,7 +767,7 @@ pub fn default_configuration(sess: &Session) -> CrateConfig {
     }
     ret.insert((sym::target_arch, Some(Symbol::intern(arch))));
     ret.insert((sym::target_endian, Some(Symbol::intern(end))));
-    ret.insert((sym::target_pointer_width, Some(Symbol::intern(wordsz))));
+    ret.insert((sym::target_pointer_width, Some(Symbol::intern(&wordsz))));
     ret.insert((sym::target_env, Some(Symbol::intern(env))));
     ret.insert((sym::target_vendor, Some(Symbol::intern(vendor))));
     if sess.target.target.options.has_elf_tls {
@@ -792,7 +792,7 @@ pub fn default_configuration(sess: &Session) -> CrateConfig {
             };
             let s = i.to_string();
             insert_atomic(&s, align);
-            if &s == wordsz {
+            if s == wordsz {
                 insert_atomic("ptr", layout.pointer_align.abi);
             }
         }
@@ -844,19 +844,18 @@ pub fn build_target_config(opts: &Options, target_override: Option<Target>) -> C
         )
     });
 
-    let ptr_width = match &target.target_pointer_width[..] {
-        "16" => 16,
-        "32" => 32,
-        "64" => 64,
-        w => early_error(
+    if !matches!(target.pointer_width, 16 | 32 | 64) {
+        early_error(
             opts.error_format,
             &format!(
                 "target specification was invalid: \
              unrecognized target-pointer-width {}",
-                w
+                target.pointer_width
             ),
-        ),
-    };
+        )
+    }
+
+    let ptr_width = target.pointer_width;
 
     Config { target, ptr_width }
 }

compiler/rustc_target/src/abi/mod.rs

@@ -164,12 +164,12 @@ impl TargetDataLayout {
             ));
         }
 
-        if dl.pointer_size.bits().to_string() != target.target_pointer_width {
+        if dl.pointer_size.bits() != target.pointer_width.into() {
             return Err(format!(
                 "inconsistent target specification: \"data-layout\" claims \
                                 pointers are {}-bit, while \"target-pointer-width\" is `{}`",
                 dl.pointer_size.bits(),
-                target.target_pointer_width
+                target.pointer_width
             ));
         }
 

compiler/rustc_target/src/spec/mod.rs

@@ -665,8 +665,8 @@ pub struct Target {
     pub llvm_target: String,
     /// String to use as the `target_endian` `cfg` variable.
     pub target_endian: String,
-    /// String to use as the `target_pointer_width` `cfg` variable.
-    pub target_pointer_width: String,
+    /// Number of bits in a pointer. Influences the `target_pointer_width` `cfg` variable.
+    pub pointer_width: u32,
     /// Width of c_int type
     pub target_c_int_width: String,
     /// OS name to use for conditional compilation.
@@ -1111,7 +1111,7 @@ impl Target {
     /// Maximum integer size in bits that this target can perform atomic
     /// operations on.
     pub fn max_atomic_width(&self) -> u64 {
-        self.options.max_atomic_width.unwrap_or_else(|| self.target_pointer_width.parse().unwrap())
+        self.options.max_atomic_width.unwrap_or_else(|| self.pointer_width.into())
     }
 
     pub fn is_abi_supported(&self, abi: Abi) -> bool {
@@ -1144,7 +1144,9 @@ impl Target {
         let mut base = Target {
             llvm_target: get_req_field("llvm-target")?,
             target_endian: get_req_field("target-endian")?,
-            target_pointer_width: get_req_field("target-pointer-width")?,
+            pointer_width: get_req_field("target-pointer-width")?
+                .parse::<u32>()
+                .map_err(|_| "target-pointer-width must be an integer".to_string())?,
             target_c_int_width: get_req_field("target-c-int-width")?,
             data_layout: get_req_field("data-layout")?,
             arch: get_req_field("arch")?,
@@ -1617,7 +1619,10 @@ impl ToJson for Target {
 
         target_val!(llvm_target);
         target_val!(target_endian);
-        target_val!(target_pointer_width);
+        d.insert(
+            "target-pointer-width".to_string(),
+            self.pointer_width.to_string().to_json(),
+        );
         target_val!(target_c_int_width);
         target_val!(arch);
         target_val!(target_os, "os");