1 -W allow-features=val -- only allow the listed language features to be enabled in code (space separated)
2 -W always-encode-mir=val -- encode MIR of all functions into the crate metadata (default: no)
3 -W assume-incomplete-release=val -- make cfg(version) treat the current version as incomplete (default: no)
4 -W asm-comments=val -- generate comments into the assembly (may change behavior) (default: no)
5 -W assert-incr-state=val -- assert that the incremental cache is in given state: either `loaded` or `not-loaded`.
6 -W binary-dep-depinfo=val -- include artifacts (sysroot, crate dependencies) used during compilation in dep-info (default: no)
7 -W branch-protection=val -- set options for branch target identification and pointer authentication on AArch64
8 -W cf-protection=val -- instrument control-flow architecture protection
9 -W cgu-partitioning-strategy=val -- the codegen unit partitioning strategy to use
10 -W chalk=val -- enable the experimental Chalk-based trait solving engine
11 -W codegen-backend=val -- the backend to use
12 -W combine-cgu=val -- combine CGUs into a single one
13 -W crate-attr=val -- inject the given attribute in the crate
14 -W debug-info-for-profiling=val -- emit discriminators and other data necessary for AutoFDO
15 -W debug-macros=val -- emit line numbers debug info inside macros (default: no)
16 -W deduplicate-diagnostics=val -- deduplicate identical diagnostics (default: yes)
17 -W dep-info-omit-d-target=val -- in dep-info output, omit targets for tracking dependencies of the dep-info files themselves (default: no)
18 -W dep-tasks=val -- print tasks that execute and the color their dep node gets (requires debug build) (default: no)
19 -W dlltool=val -- import library generation tool (windows-gnu only)
20 -W dont-buffer-diagnostics=val -- emit diagnostics rather than buffering (breaks NLL error downgrading, sorting) (default: no)
21 -W drop-tracking=val -- enables drop tracking in generators (default: no)
22 -W dual-proc-macros=val -- load proc macros for both target and host, but only link to the target (default: no)
23 -W dump-dep-graph=val -- dump the dependency graph to $RUST_DEP_GRAPH (default: /tmp/dep_graph.gv) (default: no)
24 -W dump-mir=val -- dump MIR state to file.
25 `val` is used to select which passes and functions to dump. For example:
26 `all` matches all passes and functions,
27 `foo` matches all passes for functions whose name contains 'foo',
28 `foo & ConstProp` only the 'ConstProp' pass for function names containing 'foo',
29 `foo | bar` all passes for function names containing 'foo' or 'bar'.
30 -W dump-mir-dataflow=val -- in addition to `.mir` files, create graphviz `.dot` files with dataflow results (default: no)
31 -W dump-mir-dir=val -- the directory the MIR is dumped into (default: `mir_dump`)
32 -W dump-mir-exclude-pass-number=val -- exclude the pass number when dumping MIR (used in tests) (default: no)
33 -W dump-mir-graphviz=val -- in addition to `.mir` files, create graphviz `.dot` files (and with `-Z instrument-coverage`, also create a `.dot` file for the MIR-derived coverage graph) (default: no)
34 -W dump-mir-spanview=val -- in addition to `.mir` files, create `.html` files to view spans for all `statement`s (including terminators), only `terminator` spans, or computed `block` spans (one span encompassing a block's terminator and all statements). If `-Z instrument-coverage` is also enabled, create an additional `.html` file showing the computed coverage spans.
35 -W emit-stack-sizes=val -- emit a section containing stack size metadata (default: no)
36 -W fewer-names=val -- reduce memory use by retaining fewer names within compilation artifacts (LLVM-IR) (default: no)
37 -W force-unstable-if-unmarked=val -- force all crates to be `rustc_private` unstable (default: no)
38 -W fuel=val -- set the optimization fuel quota for a crate
39 -W function-sections=val -- whether each function should go in its own section
40 -W future-incompat-test=val -- forces all lints to be future incompatible, used for internal testing (default: no)
41 -W gcc-ld=val -- implementation of ld used by cc
42 -W graphviz-dark-mode=val -- use dark-themed colors in graphviz output (default: no)
43 -W graphviz-font=val -- use the given `fontname` in graphviz output; can be overridden by setting environment variable `RUSTC_GRAPHVIZ_FONT` (default: `Courier, monospace`)
44 -W hir-stats=val -- print some statistics about AST and HIR (default: no)
45 -W human-readable-cgu-names=val -- generate human-readable, predictable names for codegen units (default: no)
46 -W identify-regions=val -- display unnamed regions as `'<id>`, using a non-ident unique id (default: no)
47 -W incremental-ignore-spans=val -- ignore spans during ICH computation -- used for testing (default: no)
48 -W incremental-info=val -- print high-level information about incremental reuse (or the lack thereof) (default: no)
49 -W incremental-relative-spans=val -- hash spans relative to their parent item for incr. comp. (default: no)
50 -W incremental-verify-ich=val -- verify incr. comp. hashes of green query instances (default: no)
51 -W inline-mir=val -- enable MIR inlining (default: no)
52 -W inline-mir-threshold=val -- a default MIR inlining threshold (default: 50)
53 -W inline-mir-hint-threshold=val -- inlining threshold for functions with inline hint (default: 100)
54 -W inline-in-all-cgus=val -- control whether `#[inline]` functions are in all CGUs
55 -W input-stats=val -- gather statistics about the input (default: no)
56 -W instrument-coverage=val -- instrument the generated code to support LLVM source-based code coverage reports (note, the compiler build config must include `profiler = true`); implies `-C symbol-mangling-version=v0`. Optional values are:
57 `=all` (implicit value)
58 `=except-unused-generics`
59 `=except-unused-functions`
61 -W instrument-mcount=val -- insert function instrument code for mcount-based tracing (default: no)
62 -W keep-hygiene-data=val -- keep hygiene data after analysis (default: no)
63 -W link-native-libraries=val -- link native libraries in the linker invocation (default: yes)
64 -W link-only=val -- link the `.rlink` file generated by `-Z no-link` (default: no)
65 -W llvm-plugins=val -- a list LLVM plugins to enable (space separated)
66 -W llvm-time-trace=val -- generate JSON tracing data file from LLVM data (default: no)
67 -W location-detail=val -- comma separated list of location details to be tracked when using caller_location valid options are `file`, `line`, and `column` (default: all)
68 -W ls=val -- list the symbols defined by a library crate (default: no)
69 -W macro-backtrace=val -- show macro backtraces (default: no)
70 -W merge-functions=val -- control the operation of the MergeFunctions LLVM pass, taking the same values as the target option of the same name
71 -W meta-stats=val -- gather metadata statistics (default: no)
72 -W mir-emit-retag=val -- emit Retagging MIR statements, interpreted e.g., by miri; implies -Zmir-opt-level=0 (default: no)
73 -W mir-enable-passes=val -- use like `-Zmir-enable-passes=+DestProp,-InstCombine`. Forces the specified passes to be enabled, overriding all other checks. Passes that are not specified are enabled or disabled by other flags as usual.
74 -W mir-opt-level=val -- MIR optimization level (0-4; default: 1 in non optimized builds and 2 in optimized builds)
75 -W move-size-limit=val -- the size at which the `large_assignments` lint starts to be emitted
76 -W mutable-noalias=val -- emit noalias metadata for mutable references (default: yes)
77 -W new-llvm-pass-manager=val -- use new LLVM pass manager (default: no)
78 -W nll-facts=val -- dump facts from NLL analysis into side files (default: no)
79 -W nll-facts-dir=val -- the directory the NLL facts are dumped into (default: `nll-facts`)
80 -W no-analysis=val -- parse and expand the source, but run no analysis
81 -W no-codegen=val -- run all passes except codegen; no output
82 -W no-generate-arange-section=val -- omit DWARF address ranges that give faster lookups
83 -W no-interleave-lints=val -- execute lints separately; allows benchmarking individual lints
84 -W no-leak-check=val -- disable the 'leak check' for subtyping; unsound, but useful for tests
85 -W no-link=val -- compile without linking
86 -W no-parallel-llvm=val -- run LLVM in non-parallel mode (while keeping codegen-units and ThinLTO)
87 -W no-unique-section-names=val -- do not use unique names for text and data sections when -Z function-sections is used
88 -W no-profiler-runtime=val -- prevent automatic injection of the profiler_builtins crate
89 -W normalize-docs=val -- normalize associated items in rustdoc when generating documentation
90 -W oom=val -- panic strategy for out-of-memory handling
91 -W osx-rpath-install-name=val -- pass `-install_name @rpath/...` to the macOS linker (default: no)
92 -W panic-abort-tests=val -- support compiling tests with panic=abort (default: no)
93 -W panic-in-drop=val -- panic strategy for panics in drops
94 -W parse-only=val -- parse only; do not compile, assemble, or link (default: no)
95 -W perf-stats=val -- print some performance-related statistics (default: no)
96 -W pick-stable-methods-before-any-unstable=val -- try to pick stable methods first before picking any unstable methods (default: yes)
97 -W plt=val -- whether to use the PLT when calling into shared libraries;
98 only has effect for PIC code on systems with ELF binaries
99 (default: PLT is disabled if full relro is enabled)
100 -W polonius=val -- enable polonius-based borrow-checker (default: no)
101 -W polymorphize=val -- perform polymorphization analysis
102 -W pre-link-arg=val -- a single extra argument to prepend the linker invocation (can be used several times)
103 -W pre-link-args=val -- extra arguments to prepend to the linker invocation (space separated)
104 -W precise-enum-drop-elaboration=val -- use a more precise version of drop elaboration for matches on enums (default: yes). This results in better codegen, but has caused miscompilations on some tier 2 platforms. See #77382 and #74551.
105 -W print-fuel=val -- make rustc print the total optimization fuel used by a crate
106 -W print-llvm-passes=val -- print the LLVM optimization passes being run (default: no)
107 -W print-mono-items=val -- print the result of the monomorphization collection pass
108 -W print-type-sizes=val -- print layout information for each type encountered (default: no)
109 -W proc-macro-backtrace=val -- show backtraces for panics during proc-macro execution (default: no)
110 -W profile=val -- insert profiling code (default: no)
111 -W profile-closures=val -- profile size of closures
112 -W profile-emit=val -- file path to emit profiling data at runtime when using 'profile' (default based on relative source path)
113 -W profiler-runtime=val -- name of the profiler runtime crate to automatically inject (default: `profiler_builtins`)
114 -W profile-sample-use=val -- use the given `.prof` file for sampled profile-guided optimization (also known as AutoFDO)
115 -W query-dep-graph=val -- enable queries of the dependency graph for regression testing (default: no)
116 -W randomize-layout=val -- randomize the layout of types (default: no)
117 -W layout-seed=val -- seed layout randomization
118 -W relax-elf-relocations=val -- whether ELF relocations can be relaxed
119 -W relro-level=val -- choose which RELRO level to use
120 -W remap-cwd-prefix=val -- remap paths under the current working directory to this path prefix
121 -W simulate-remapped-rust-src-base=val -- simulate the effect of remap-debuginfo = true at bootstrapping by remapping path to rust's source base directory. only meant for testing purposes
122 -W report-delayed-bugs=val -- immediately print bugs registered with `delay_span_bug` (default: no)
123 -W sanitizer=val -- use a sanitizer
124 -W sanitizer-memory-track-origins=val -- enable origins tracking in MemorySanitizer
125 -W sanitizer-recover=val -- enable recovery for selected sanitizers
126 -W saturating-float-casts=val -- make float->int casts UB-free: numbers outside the integer type's range are clipped to the max/min integer respectively, and NaN is mapped to 0 (default: yes)
127 -W save-analysis=val -- write syntax and type analysis (in JSON format) information, in addition to normal output (default: no)
128 -W self-profile=val -- run the self profiler and output the raw event data
129 -W self-profile-events=val -- specify the events recorded by the self profiler;
130 for example: `-Z self-profile-events=default,query-keys`
131 all options: none, all, default, generic-activity, query-provider, query-cache-hit
132 query-blocked, incr-cache-load, incr-result-hashing, query-keys, function-args, args, llvm, artifact-sizes
133 -W self-profile-counter=val -- counter used by the self profiler (default: `wall-time`), one of:
134 `wall-time` (monotonic clock, i.e. `std::time::Instant`)
135 `instructions:u` (retired instructions, userspace-only)
136 `instructions-minus-irqs:u` (subtracting hardware interrupt counts for extra accuracy)
137 -W share-generics=val -- make the current crate share its generic instantiations
138 -W show-span=val -- show spans for compiler debugging (expr|pat|ty)
139 -W span-debug=val -- forward proc_macro::Span's `Debug` impl to `Span`
140 -W span-free-formats=val -- exclude spans when debug-printing compiler state (default: no)
141 -W src-hash-algorithm=val -- hash algorithm of source files in debug info (`md5`, `sha1`, or `sha256`)
142 -W stack-protector=val -- control stack smash protection strategy (`rustc --print stack-protector-strategies` for details)
143 -W strict-init-checks=val -- control if mem::uninitialized and mem::zeroed panic on more UB
144 -W strip=val -- tell the linker which information to strip (`none` (default), `debuginfo` or `symbols`)
145 -W split-dwarf-kind=val -- split dwarf variant (only if -Csplit-debuginfo is enabled and on relevant platform)
148 `split`: sections which do not require relocation are written into a DWARF object (`.dwo`)
149 file which is ignored by the linker
150 `single`: sections which do not require relocation are written into object file but ignored
152 -W split-dwarf-inlining=val -- provide minimal debug info in the object/executable to facilitate online symbolication/stack traces in the absence of .dwo/.dwp files when using Split DWARF
153 -W symbol-mangling-version=val -- which mangling version to use for symbol names ('legacy' (default) or 'v0')
154 -W teach=val -- show extended diagnostic help (default: no)
155 -W temps-dir=val -- the directory the intermediate files are written to
156 -W terminal-width=val -- set the current terminal width
157 -W translate-lang=val -- language identifier for diagnostic output
158 -W translate-additional-ftl=val -- additional fluent translation to preferentially use (for testing translation)
159 -W translate-directionality-markers=val -- emit directionality isolation markers in translated diagnostics
160 -W tune-cpu=val -- select processor to schedule for (`rustc --print target-cpus` for details)
161 -W thinlto=val -- enable ThinLTO when possible
162 -W thir-unsafeck=val -- use the THIR unsafety checker (default: no)
163 -W threads=val -- use a thread pool with N threads
164 -W time=val -- measure time of rustc processes (default: no)
165 -W time-llvm-passes=val -- measure time of each LLVM pass (default: no)
166 -W time-passes=val -- measure time of each rustc pass (default: no)
167 -W tls-model=val -- choose the TLS model to use (`rustc --print tls-models` for details)
168 -W trace-macros=val -- for every macro invocation, print its name and arguments (default: no)
169 -W translate-remapped-path-to-local-path=val -- translate remapped paths into local paths when possible (default: yes)
170 -W trap-unreachable=val -- generate trap instructions for unreachable intrinsics (default: use target setting, usually yes)
171 -W treat-err-as-bug=val -- treat error number `val` that occurs as bug
172 -W trim-diagnostic-paths=val -- in diagnostics, use heuristics to shorten paths referring to items
173 -W ui-testing=val -- emit compiler diagnostics in a form suitable for UI testing (default: no)
174 -W uninit-const-chunk-threshold=val -- allow generating const initializers with mixed init/uninit chunks, and set the maximum number of chunks for which this is allowed (default: 16)
175 -W unleash-the-miri-inside-of-you=val -- take the brakes off const evaluation. NOTE: this is unsound (default: no)
176 -W unpretty=val -- present the input source, unstable (and less-pretty) variants;
177 `normal`, `identified`,
178 `expanded`, `expanded,identified`,
179 `expanded,hygiene` (with internal representations),
180 `ast-tree` (raw AST before expansion),
181 `ast-tree,expanded` (raw AST after expansion),
182 `hir` (the HIR), `hir,identified`,
183 `hir,typed` (HIR with types for each node),
184 `hir-tree` (dump the raw HIR),
185 `mir` (the MIR), or `mir-cfg` (graphviz formatted MIR)
186 -W unsound-mir-opts=val -- enable unsound and buggy MIR optimizations (default: no)
187 -W unstable-options=val -- adds unstable command line options to rustc interface (default: no)
188 -W use-ctors-section=val -- use legacy .ctors section for initializers rather than .init_array
189 -W validate-mir=val -- validate MIR after each transformation
190 -W verbose=val -- in general, enable more debug printouts (default: no)
191 -W verify-llvm-ir=val -- verify LLVM IR (default: no)
192 -W virtual-function-elimination=val -- enables dead virtual function elimination optimization. Requires `-Clto[=[fat,yes]]`
193 -W wasi-exec-model=val -- whether to build a wasi command or reactor