Convenience funcs for some_option.unwrap_or(...)

This ensures consistent handling of default values for options that are
None if not specified on the command line.

compiler/rustc_interface/src/tests.rs

@@ -561,7 +561,7 @@ fn test_debugging_options_tracking_hash() {
     tracked!(link_only, true);
     tracked!(merge_functions, Some(MergeFunctions::Disabled));
     tracked!(mir_emit_retag, true);
-    tracked!(mir_opt_level, Some(3));
+    tracked!(mir_opt_level, 3);
     tracked!(mutable_noalias, true);
     tracked!(new_llvm_pass_manager, true);
     tracked!(no_codegen, true);

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -663,12 +663,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             no_builtins: tcx.sess.contains_name(&attrs, sym::no_builtins),
             panic_runtime: tcx.sess.contains_name(&attrs, sym::panic_runtime),
             profiler_runtime: tcx.sess.contains_name(&attrs, sym::profiler_runtime),
-            symbol_mangling_version: tcx
-                .sess
-                .opts
-                .debugging_opts
-                .symbol_mangling_version
-                .unwrap_or(SymbolManglingVersion::default()),
+            symbol_mangling_version: tcx.sess.opts.debugging_opts.get_symbol_mangling_version(),
 
             crate_deps,
             dylib_dependency_formats,

compiler/rustc_mir/src/transform/const_prop.rs

@@ -22,7 +22,6 @@ use rustc_middle::ty::subst::{InternalSubsts, Subst};
 use rustc_middle::ty::{
     self, ConstInt, ConstKind, Instance, ParamEnv, ScalarInt, Ty, TyCtxt, TypeFoldable,
 };
-use rustc_session::config::MIR_OPT_LEVEL_DEFAULT;
 use rustc_session::lint;
 use rustc_span::{def_id::DefId, Span};
 use rustc_target::abi::{HasDataLayout, LayoutOf, Size, TargetDataLayout};
@@ -709,7 +708,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
             return None;
         }
 
-        if self.tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT) >= 3 {
+        if self.tcx.sess.opts.debugging_opts.mir_opt_level >= 3 {
             self.eval_rvalue_with_identities(rvalue, place)
         } else {
             self.use_ecx(|this| this.ecx.eval_rvalue_into_place(rvalue, place))
@@ -887,8 +886,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
 
     /// Returns `true` if and only if this `op` should be const-propagated into.
     fn should_const_prop(&mut self, op: OpTy<'tcx>) -> bool {
-        let mir_opt_level =
-            self.tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT);
+        let mir_opt_level = self.tcx.sess.opts.debugging_opts.mir_opt_level;
 
         if mir_opt_level == 0 {
             return false;
@@ -1058,7 +1056,7 @@ impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
 
         // Only const prop copies and moves on `mir_opt_level=2` as doing so
         // currently slightly increases compile time in some cases.
-        if self.tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT) >= 2 {
+        if self.tcx.sess.opts.debugging_opts.mir_opt_level >= 2 {
             self.propagate_operand(operand)
         }
     }

compiler/rustc_mir/src/transform/dest_prop.rs

@@ -115,7 +115,6 @@ use rustc_middle::mir::{
     Rvalue, Statement, StatementKind, Terminator, TerminatorKind,
 };
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_session::config::MIR_OPT_LEVEL_DEFAULT;
 
 // Empirical measurements have resulted in some observations:
 // - Running on a body with a single block and 500 locals takes barely any time
@@ -130,7 +129,7 @@ impl<'tcx> MirPass<'tcx> for DestinationPropagation {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         // Only run at mir-opt-level=2 or higher for now (we don't fix up debuginfo and remove
         // storage statements at the moment).
-        if tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT) <= 1 {
+        if tcx.sess.opts.debugging_opts.mir_opt_level <= 1 {
             return;
         }
 

compiler/rustc_mir/src/transform/early_otherwise_branch.rs

@@ -1,7 +1,6 @@
 use crate::{transform::MirPass, util::patch::MirPatch};
 use rustc_middle::mir::*;
 use rustc_middle::ty::{Ty, TyCtxt};
-use rustc_session::config::MIR_OPT_LEVEL_DEFAULT;
 use std::fmt::Debug;
 
 use super::simplify::simplify_cfg;
@@ -27,7 +26,7 @@ pub struct EarlyOtherwiseBranch;
 
 impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT) < 2 {
+        if tcx.sess.opts.debugging_opts.mir_opt_level < 2 {
             return;
         }
         trace!("running EarlyOtherwiseBranch on {:?}", body.source);

compiler/rustc_mir/src/transform/inline.rs

@@ -9,7 +9,6 @@ use rustc_middle::mir::visit::*;
 use rustc_middle::mir::*;
 use rustc_middle::ty::subst::Subst;
 use rustc_middle::ty::{self, ConstKind, Instance, InstanceDef, ParamEnv, Ty, TyCtxt};
-use rustc_session::config::MIR_OPT_LEVEL_DEFAULT;
 use rustc_span::{hygiene::ExpnKind, ExpnData, Span};
 use rustc_target::spec::abi::Abi;
 
@@ -38,7 +37,7 @@ struct CallSite<'tcx> {
 
 impl<'tcx> MirPass<'tcx> for Inline {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT) < 2 {
+        if tcx.sess.opts.debugging_opts.mir_opt_level < 2 {
             return;
         }
 

compiler/rustc_mir/src/transform/match_branches.rs

@@ -1,7 +1,6 @@
 use crate::transform::MirPass;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
-use rustc_session::config::MIR_OPT_LEVEL_DEFAULT;
 
 pub struct MatchBranchSimplification;
 
@@ -39,7 +38,7 @@ pub struct MatchBranchSimplification;
 
 impl<'tcx> MirPass<'tcx> for MatchBranchSimplification {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT) <= 1 {
+        if tcx.sess.opts.debugging_opts.mir_opt_level <= 1 {
             return;
         }
 

compiler/rustc_mir/src/transform/mod.rs

@@ -10,7 +10,6 @@ use rustc_middle::mir::visit::Visitor as _;
 use rustc_middle::mir::{traversal, Body, ConstQualifs, MirPhase, Promoted};
 use rustc_middle::ty::query::Providers;
 use rustc_middle::ty::{self, TyCtxt, TypeFoldable};
-use rustc_session::config::MIR_OPT_LEVEL_DEFAULT;
 use rustc_span::{Span, Symbol};
 use std::borrow::Cow;
 
@@ -374,7 +373,7 @@ fn run_post_borrowck_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tc
 }
 
 fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-    let mir_opt_level = tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT);
+    let mir_opt_level = tcx.sess.opts.debugging_opts.mir_opt_level;
 
     // Lowering generator control-flow and variables has to happen before we do anything else
     // to them. We run some optimizations before that, because they may be harder to do on the state

compiler/rustc_mir/src/transform/multiple_return_terminators.rs

@@ -5,13 +5,12 @@ use crate::transform::{simplify, MirPass};
 use rustc_index::bit_set::BitSet;
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
-use rustc_session::config::MIR_OPT_LEVEL_DEFAULT;
 
 pub struct MultipleReturnTerminators;
 
 impl<'tcx> MirPass<'tcx> for MultipleReturnTerminators {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT) < 3 {
+        if tcx.sess.opts.debugging_opts.mir_opt_level < 3 {
             return;
         }
 

compiler/rustc_mir/src/transform/nrvo.rs

@@ -5,7 +5,6 @@ use rustc_index::bit_set::HybridBitSet;
 use rustc_middle::mir::visit::{MutVisitor, NonUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::{self, BasicBlock, Local, Location};
 use rustc_middle::ty::TyCtxt;
-use rustc_session::config::MIR_OPT_LEVEL_DEFAULT;
 
 use crate::transform::MirPass;
 
@@ -35,7 +34,7 @@ pub struct RenameReturnPlace;
 
 impl<'tcx> MirPass<'tcx> for RenameReturnPlace {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut mir::Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT) == 0 {
+        if tcx.sess.opts.debugging_opts.mir_opt_level == 0 {
             return;
         }
 

compiler/rustc_mir/src/transform/unreachable_prop.rs

@@ -7,13 +7,12 @@ use crate::transform::MirPass;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_middle::mir::*;
 use rustc_middle::ty::TyCtxt;
-use rustc_session::config::MIR_OPT_LEVEL_DEFAULT;
 
 pub struct UnreachablePropagation;
 
 impl MirPass<'_> for UnreachablePropagation {
     fn run_pass<'tcx>(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
-        if tcx.sess.opts.debugging_opts.mir_opt_level.unwrap_or(MIR_OPT_LEVEL_DEFAULT) < 3 {
+        if tcx.sess.opts.debugging_opts.mir_opt_level < 3 {
             // Enable only under -Zmir-opt-level=3 as in some cases (check the deeply-nested-opt
             // perf benchmark) LLVM may spend quite a lot of time optimizing the generated code.
             return;

compiler/rustc_session/src/config.rs

@@ -174,8 +174,6 @@ pub enum MirSpanview {
     Block,
 }
 
-pub const MIR_OPT_LEVEL_DEFAULT: usize = 1;
-
 #[derive(Clone, PartialEq, Hash)]
 pub enum LinkerPluginLto {
     LinkerPlugin(PathBuf),
@@ -214,12 +212,6 @@ pub enum SymbolManglingVersion {
     V0,
 }
 
-impl SymbolManglingVersion {
-    pub fn default() -> Self {
-        SymbolManglingVersion::Legacy
-    }
-}
-
 impl_stable_hash_via_hash!(SymbolManglingVersion);
 
 #[derive(Clone, Copy, Debug, PartialEq, Hash)]
@@ -700,6 +692,10 @@ impl DebuggingOptions {
             deduplicate_diagnostics: self.deduplicate_diagnostics,
         }
     }
+
+    pub fn get_symbol_mangling_version(&self) -> SymbolManglingVersion {
+        self.symbol_mangling_version.unwrap_or(SymbolManglingVersion::Legacy)
+    }
 }
 
 // The type of entry function, so users can have their own entry functions
@@ -1779,18 +1775,15 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
             Some(SymbolManglingVersion::V0) => {}
         }
 
-        match debugging_opts.mir_opt_level {
-            Some(level) if level > 1 => {
-                early_warn(
-                    error_format,
-                    &format!(
-                        "`-Z mir-opt-level={}` (any level > 1) enables function inlining, which \
-                        limits the effectiveness of `-Z instrument-coverage`.",
-                        level,
-                    ),
-                );
-            }
-            _ => {}
+        if debugging_opts.mir_opt_level > 1 {
+            early_warn(
+                error_format,
+                &format!(
+                    "`-Z mir-opt-level={}` (any level > 1) enables function inlining, which \
+                    limits the effectiveness of `-Z instrument-coverage`.",
+                    debugging_opts.mir_opt_level,
+                ),
+            );
         }
     }
 

compiler/rustc_session/src/options.rs

@@ -970,7 +970,7 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
     mir_emit_retag: bool = (false, parse_bool, [TRACKED],
         "emit Retagging MIR statements, interpreted e.g., by miri; implies -Zmir-opt-level=0 \
         (default: no)"),
-    mir_opt_level: Option<usize> = (None, parse_opt_uint, [TRACKED],
+    mir_opt_level: usize = (1, parse_uint, [TRACKED],
         "MIR optimization level (0-3; default: 1)"),
     mutable_noalias: bool = (false, parse_bool, [TRACKED],
         "emit noalias metadata for mutable references (default: no)"),

compiler/rustc_symbol_mangling/src/lib.rs

@@ -245,11 +245,7 @@ fn compute_symbol_name(
     // 2. we favor `instantiating_crate` where possible (i.e. when `Some`)
     let mangling_version_crate = instantiating_crate.unwrap_or(def_id.krate);
     let mangling_version = if mangling_version_crate == LOCAL_CRATE {
-        tcx.sess
-            .opts
-            .debugging_opts
-            .symbol_mangling_version
-            .unwrap_or(SymbolManglingVersion::default())
+        tcx.sess.opts.debugging_opts.get_symbol_mangling_version()
     } else {
         tcx.symbol_mangling_version(mangling_version_crate)
     };

src/tools/clippy/src/driver.rs

@@ -85,7 +85,7 @@ impl rustc_driver::Callbacks for ClippyCallbacks {
         // run on the unoptimized MIR. On the other hand this results in some false negatives. If
         // MIR passes can be enabled / disabled separately, we should figure out, what passes to
         // use for Clippy.
-        config.opts.debugging_opts.mir_opt_level = Some(0);
+        config.opts.debugging_opts.mir_opt_level = 0;
     }
 }