Auto merge of #98212 - petrochenkov:addlinkargs, r=lqd

rustc_target: Add convenience functions for adding linker arguments

They ensure that lld and non-lld linker flavors get the same set of arguments.

The second commit also adds some tests checking for linker argument inconsistencies, and tweaks some arguments to fix those inconsistencies.

1 files changed, 49 insertions, 56 deletions

diff --git a/compiler/rustc_target/src/spec/wasm_base.rs b/compiler/rustc_target/src/spec/wasm_base.rs
index de7b7374af3..5736402ae14 100644
--- a/compiler/rustc_target/src/spec/wasm_base.rs
+++ b/compiler/rustc_target/src/spec/wasm_base.rs
@@ -1,63 +1,56 @@
 use super::crt_objects::CrtObjectsFallback;
 use super::{cvs, LinkerFlavor, LldFlavor, PanicStrategy, RelocModel, TargetOptions, TlsModel};
-use std::collections::BTreeMap;
 
 pub fn options() -> TargetOptions {
-    let mut lld_args = Vec::new();
-    let mut clang_args = Vec::new();
-    let mut arg = |arg: &'static str| {
-        lld_args.push(arg.into());
-        clang_args.push(format!("-Wl,{}", arg).into());
-    };
-
-    // By default LLD only gives us one page of stack (64k) which is a
-    // little small. Default to a larger stack closer to other PC platforms
-    // (1MB) and users can always inject their own link-args to override this.
-    arg("-z");
-    arg("stack-size=1048576");
-
-    // By default LLD's memory layout is:
-    //
-    // 1. First, a blank page
-    // 2. Next, all static data
-    // 3. Finally, the main stack (which grows down)
-    //
-    // This has the unfortunate consequence that on stack overflows you
-    // corrupt static data and can cause some exceedingly weird bugs. To
-    // help detect this a little sooner we instead request that the stack is
-    // placed before static data.
-    //
-    // This means that we'll generate slightly larger binaries as references
-    // to static data will take more bytes in the ULEB128 encoding, but
-    // stack overflow will be guaranteed to trap as it underflows instead of
-    // corrupting static data.
-    arg("--stack-first");
-
-    // FIXME we probably shouldn't pass this but instead pass an explicit list
-    // of symbols we'll allow to be undefined. We don't currently have a
-    // mechanism of knowing, however, which symbols are intended to be imported
-    // from the environment and which are intended to be imported from other
-    // objects linked elsewhere. This is a coarse approximation but is sure to
-    // hide some bugs and frustrate someone at some point, so we should ideally
-    // work towards a world where we can explicitly list symbols that are
-    // supposed to be imported and have all other symbols generate errors if
-    // they remain undefined.
-    arg("--allow-undefined");
-
-    // Rust code should never have warnings, and warnings are often
-    // indicative of bugs, let's prevent them.
-    arg("--fatal-warnings");
-
-    // LLD only implements C++-like demangling, which doesn't match our own
-    // mangling scheme. Tell LLD to not demangle anything and leave it up to
-    // us to demangle these symbols later. Currently rustc does not perform
-    // further demangling, but tools like twiggy and wasm-bindgen are intended
-    // to do so.
-    arg("--no-demangle");
-
-    let mut pre_link_args = BTreeMap::new();
-    pre_link_args.insert(LinkerFlavor::Lld(LldFlavor::Wasm), lld_args);
-    pre_link_args.insert(LinkerFlavor::Gcc, clang_args);
+    macro_rules! args {
+        ($prefix:literal) => {
+            &[
+                // By default LLD only gives us one page of stack (64k) which is a
+                // little small. Default to a larger stack closer to other PC platforms
+                // (1MB) and users can always inject their own link-args to override this.
+                concat!($prefix, "-z"),
+                concat!($prefix, "stack-size=1048576"),
+                // By default LLD's memory layout is:
+                //
+                // 1. First, a blank page
+                // 2. Next, all static data
+                // 3. Finally, the main stack (which grows down)
+                //
+                // This has the unfortunate consequence that on stack overflows you
+                // corrupt static data and can cause some exceedingly weird bugs. To
+                // help detect this a little sooner we instead request that the stack is
+                // placed before static data.
+                //
+                // This means that we'll generate slightly larger binaries as references
+                // to static data will take more bytes in the ULEB128 encoding, but
+                // stack overflow will be guaranteed to trap as it underflows instead of
+                // corrupting static data.
+                concat!($prefix, "--stack-first"),
+                // FIXME we probably shouldn't pass this but instead pass an explicit list
+                // of symbols we'll allow to be undefined. We don't currently have a
+                // mechanism of knowing, however, which symbols are intended to be imported
+                // from the environment and which are intended to be imported from other
+                // objects linked elsewhere. This is a coarse approximation but is sure to
+                // hide some bugs and frustrate someone at some point, so we should ideally
+                // work towards a world where we can explicitly list symbols that are
+                // supposed to be imported and have all other symbols generate errors if
+                // they remain undefined.
+                concat!($prefix, "--allow-undefined"),
+                // Rust code should never have warnings, and warnings are often
+                // indicative of bugs, let's prevent them.
+                concat!($prefix, "--fatal-warnings"),
+                // LLD only implements C++-like demangling, which doesn't match our own
+                // mangling scheme. Tell LLD to not demangle anything and leave it up to
+                // us to demangle these symbols later. Currently rustc does not perform
+                // further demangling, but tools like twiggy and wasm-bindgen are intended
+                // to do so.
+                concat!($prefix, "--no-demangle"),
+            ]
+        };
+    }
+
+    let mut pre_link_args = TargetOptions::link_args(LinkerFlavor::Lld(LldFlavor::Wasm), args!(""));
+    super::add_link_args(&mut pre_link_args, LinkerFlavor::Gcc, args!("-Wl,"));
 
     TargetOptions {
         is_like_wasm: true,