Don't add `argc` and `argv` arguments to `main` on WASI. #65576

sunfishcode · 2019-10-18T22:18:09Z

Add a target setting to allow targets to specify whether the generated
main function should be passed argc and argv arguments. Set it
to false on wasm32-wasi, since WASI's args::args() calls into the
WASI APIs itself. This will allow the WASI toolchain to avoid linking
and running command-line argument initialization code when the arguments
aren't actually needed.

Add a target setting to allow targets to specify whether the generated `main` function should be passed `argc` and `argv` arguments. Set it to false on wasm32-wasi, since WASI's `args::args()` calls into the WASI APIs itself. This will allow the WASI toolchain to avoid linking and running command-line argument initialization code when the arguments aren't actually needed.

rust-highfive · 2019-10-18T22:18:12Z

r? @cramertj

(rust_highfive has picked a reviewer for you, use r? to override)

sunfishcode · 2019-10-18T22:18:33Z

r? @alexcrichton

alexcrichton · 2019-10-18T22:29:15Z

@bors: r+

bors · 2019-10-18T22:29:17Z

📌 Commit b25e323 has been approved by alexcrichton

Centril · 2019-10-19T04:08:23Z

src/librustc_codegen_ssa/base.rs

@@ -414,8 +414,11 @@ pub fn maybe_create_entry_wrapper<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(cx: &'
        rust_main_def_id: DefId,
        use_start_lang_item: bool,
    ) {
-        let llfty =
-            cx.type_func(&[cx.type_int(), cx.type_ptr_to(cx.type_i8p())], cx.type_int());
+        let llfty = if cx.sess().target.target.options.main_needs_argc_argv {


I think this wants a comment.

Centril · 2019-10-19T04:09:48Z

src/librustc_codegen_ssa/base.rs

-        let param_argv = bx.get_param(1);
-        let arg_argc = bx.intcast(param_argc, cx.type_isize(), true);
-        let arg_argv = param_argv;
+        let (arg_argc, arg_argv) = if cx.sess().target.target.options.main_needs_argc_argv {


The function is already large; this bit could be extracted into its own (+ appropriate doc comment).

Centril · 2019-10-19T04:10:32Z

src/librustc_codegen_ssa/base.rs

-        let arg_argc = bx.intcast(param_argc, cx.type_isize(), true);
-        let arg_argv = param_argv;
+        let (arg_argc, arg_argv) = if cx.sess().target.target.options.main_needs_argc_argv {
+            // Params from native main() used as args for rust start function


Suggested change

// Params from native main() used as args for rust start function

// Params from native `main()` used as args for rust start function

Centril · 2019-10-19T04:10:57Z

src/librustc_codegen_ssa/base.rs

+            let arg_argv = param_argv;
+            (arg_argc, arg_argv)
+        } else {
+            // The Rust start function doesn't need argc and argv, so just pass zeros.


Suggested change

// The Rust start function doesn't need argc and argv, so just pass zeros.

// The Rust start function doesn't need `argc` and `argv`, so just pass zeros.

Centril · 2019-10-19T04:12:30Z

@sunfishcode I noticed this was r+ed now -- if this PR is merged before, can you follow up to address my review comments?

…=alexcrichton Don't add `argc` and `argv` arguments to `main` on WASI. Add a target setting to allow targets to specify whether the generated `main` function should be passed `argc` and `argv` arguments. Set it to false on wasm32-wasi, since WASI's `args::args()` calls into the WASI APIs itself. This will allow the WASI toolchain to avoid linking and running command-line argument initialization code when the arguments aren't actually needed.

@ghost

Rollup of 6 pull requests Successful merges: - #65174 (Fix zero-size uninitialized boxes) - #65252 (expand: Simplify expansion of derives) - #65485 (Suppress ICE when validators disagree on `LiveDrop`s in presence of `&mut`) - #65542 (Refer to "associated functions" instead of "static methods") - #65545 (More symbol cleanups) - #65576 (Don't add `argc` and `argv` arguments to `main` on WASI.) Failed merges: r? @ghost

sunfishcode · 2019-10-21T17:53:18Z

@Centril The PR was indeed merged; I'll submit a new PR to address your feedback.

This makes a few code cleanups to follow up on the review comments in rust-lang#65576.

@Centril

Code cleanups following up on rust-lang#65576. This makes a few code cleanups to follow up on the review comments in rust-lang#65576. r? @Centril

@Centril

Code cleanups following up on rust-lang#65576. This makes a few code cleanups to follow up on the review comments in rust-lang#65576. r? @Centril

@ghost

Rollup of 14 pull requests Successful merges: - #64145 (Target-feature documented as unsafe) - #65007 (Mention keyword closing policy) - #65417 (Add more coherence tests) - #65507 (Fix test style in unused parentheses lint test) - #65591 (Add long error explanation for E0588) - #65617 (Fix WASI sleep impl) - #65656 (Add option to disable keyboard shortcuts in docs) - #65678 (Add long error explanation for E0728) - #65681 (Code cleanups following up on #65576.) - #65686 (refactor and move `maybe_append` ) - #65688 (Add some tests for fixed ICEs) - #65689 (bring back some Debug instances for Miri) - #65695 (self-profiling: Remove module names from some event-ids in codegen backend.) - #65706 (Add missing space in librustdoc) Failed merges: r? @ghost

sunfishcode requested a review from alexcrichton October 18, 2019 22:18

rust-highfive assigned cramertj Oct 18, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Oct 18, 2019

rust-highfive assigned alexcrichton and unassigned cramertj Oct 18, 2019

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 18, 2019

Centril reviewed Oct 19, 2019

View reviewed changes

Centril mentioned this pull request Oct 19, 2019

Rollup of 6 pull requests #65588

Merged

bors merged commit b25e323 into rust-lang:master Oct 19, 2019

sunfishcode deleted the main-needs-argc-argv branch October 21, 2019 17:51

sunfishcode mentioned this pull request Oct 22, 2019

Code cleanups following up on #65576. #65681

Merged

JohnTitor pushed a commit to JohnTitor/rust that referenced this pull request Oct 22, 2019

Code cleanups following up on rust-lang#65576.

3f1af90

This makes a few code cleanups to follow up on the review comments in rust-lang#65576.

JohnTitor mentioned this pull request Oct 22, 2019

Rollup of 10 pull requests #65702

Closed

JohnTitor mentioned this pull request Oct 23, 2019

Rollup of 14 pull requests #65716

Merged

davidtwco mentioned this pull request Sep 20, 2023

target tier policy compliance #116004

Closed

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Don't add `argc` and `argv` arguments to `main` on WASI. #65576

Don't add `argc` and `argv` arguments to `main` on WASI. #65576

sunfishcode commented Oct 18, 2019

rust-highfive commented Oct 18, 2019

sunfishcode commented Oct 18, 2019

alexcrichton commented Oct 18, 2019

bors commented Oct 18, 2019

Centril Oct 19, 2019

Centril Oct 19, 2019

Centril Oct 19, 2019

Centril Oct 19, 2019

Centril commented Oct 19, 2019

sunfishcode commented Oct 21, 2019

	// Params from native main() used as args for rust start function
	// Params from native `main()` used as args for rust start function

	// The Rust start function doesn't need argc and argv, so just pass zeros.
	// The Rust start function doesn't need `argc` and `argv`, so just pass zeros.

Don't add argc and argv arguments to main on WASI. #65576

Don't add argc and argv arguments to main on WASI. #65576

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sunfishcode commented Oct 18, 2019

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Centril commented Oct 19, 2019

sunfishcode commented Oct 21, 2019

Don't add `argc` and `argv` arguments to `main` on WASI. #65576

Don't add `argc` and `argv` arguments to `main` on WASI. #65576