Auto merge of #83593 - petrochenkov:nounwrap, r=nagisa

rustc_target: Avoid unwraps when adding linker flags

These `unwrap`s assume that some linker flags were already added by `*_base::opts()` methods, but that's doesn't necessarily remain the case when we are reducing the number of flags hardcoded in targets, as https://github.com/rust-lang/rust/pull/83587 shows.

r? `@nagisa`

compiler/rustc_target/src/spec/android_base.rs

@@ -6,8 +6,8 @@ pub fn opts() -> TargetOptions {
     // Many of the symbols defined in compiler-rt are also defined in libgcc.
     // Android's linker doesn't like that by default.
     base.pre_link_args
-        .get_mut(&LinkerFlavor::Gcc)
-        .unwrap()
+        .entry(LinkerFlavor::Gcc)
+        .or_default()
         .push("-Wl,--allow-multiple-definition".to_string());
     base.dwarf_version = Some(2);
     base.position_independent_executables = true;

compiler/rustc_target/src/spec/armv7_linux_androideabi.rs

@@ -12,7 +12,7 @@ pub fn target() -> Target {
     let mut base = super::android_base::opts();
     base.features = "+v7,+thumb-mode,+thumb2,+vfp3,-d32,-neon".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-march=armv7-a".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-march=armv7-a".to_string());
 
     Target {
         llvm_target: "armv7-none-linux-android".to_string(),

compiler/rustc_target/src/spec/i686_pc_windows_gnu.rs

@@ -12,8 +12,8 @@ pub fn target() -> Target {
     // Mark all dynamic libraries and executables as compatible with the larger 4GiB address
     // space available to x86 Windows binaries on x86_64.
     base.pre_link_args
-        .get_mut(&LinkerFlavor::Gcc)
-        .unwrap()
+        .entry(LinkerFlavor::Gcc)
+        .or_default()
         .push("-Wl,--large-address-aware".to_string());
 
     Target {

compiler/rustc_target/src/spec/i686_pc_windows_msvc.rs

@@ -14,10 +14,10 @@ pub fn target() -> Target {
         // https://docs.microsoft.com/en-us/cpp/build/reference/safeseh-image-has-safe-exception-handlers
         "/SAFESEH".to_string(),
     ];
-    base.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().extend(pre_link_args_msvc.clone());
+    base.pre_link_args.entry(LinkerFlavor::Msvc).or_default().extend(pre_link_args_msvc.clone());
     base.pre_link_args
-        .get_mut(&LinkerFlavor::Lld(LldFlavor::Link))
-        .unwrap()
+        .entry(LinkerFlavor::Lld(LldFlavor::Link))
+        .or_default()
         .extend(pre_link_args_msvc);
 
     Target {

compiler/rustc_target/src/spec/i686_unknown_freebsd.rs

@@ -4,7 +4,7 @@ pub fn target() -> Target {
     let mut base = super::freebsd_base::opts();
     base.cpu = "pentium4".to_string();
     base.max_atomic_width = Some(64);
-    let pre_link_args = base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap();
+    let pre_link_args = base.pre_link_args.entry(LinkerFlavor::Gcc).or_default();
     pre_link_args.push("-m32".to_string());
     pre_link_args.push("-Wl,-znotext".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };

compiler/rustc_target/src/spec/i686_unknown_linux_gnu.rs

@@ -4,7 +4,7 @@ pub fn target() -> Target {
     let mut base = super::linux_gnu_base::opts();
     base.cpu = "pentium4".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m32".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m32".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
 
     Target {

compiler/rustc_target/src/spec/i686_unknown_linux_musl.rs

@@ -4,8 +4,8 @@ pub fn target() -> Target {
     let mut base = super::linux_musl_base::opts();
     base.cpu = "pentium4".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m32".to_string());
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-Wl,-melf_i386".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m32".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-Wl,-melf_i386".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
 
     // The unwinder used by i686-unknown-linux-musl, the LLVM libunwind

compiler/rustc_target/src/spec/i686_unknown_openbsd.rs

@@ -4,8 +4,8 @@ pub fn target() -> Target {
     let mut base = super::openbsd_base::opts();
     base.cpu = "pentium4".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m32".to_string());
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-fuse-ld=lld".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m32".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-fuse-ld=lld".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
 
     Target {

compiler/rustc_target/src/spec/i686_uwp_windows_gnu.rs

@@ -11,8 +11,8 @@ pub fn target() -> Target {
     // Mark all dynamic libraries and executables as compatible with the larger 4GiB address
     // space available to x86 Windows binaries on x86_64.
     base.pre_link_args
-        .get_mut(&LinkerFlavor::Gcc)
-        .unwrap()
+        .entry(LinkerFlavor::Gcc)
+        .or_default()
         .push("-Wl,--large-address-aware".to_string());
 
     Target {

compiler/rustc_target/src/spec/powerpc64_unknown_freebsd.rs

@@ -4,7 +4,7 @@
 pub fn target() -> Target {
     let mut base = super::freebsd_base::opts();
     base.cpu = "ppc64".to_string();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.max_atomic_width = Some(64);
 
     Target {

compiler/rustc_target/src/spec/powerpc64_unknown_linux_gnu.rs

@@ -4,7 +4,7 @@
 pub fn target() -> Target {
     let mut base = super::linux_gnu_base::opts();
     base.cpu = "ppc64".to_string();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.max_atomic_width = Some(64);
 
     // ld.so in at least RHEL6 on ppc64 has a bug related to BIND_NOW, so only enable partial RELRO

compiler/rustc_target/src/spec/powerpc64_unknown_linux_musl.rs

@@ -4,7 +4,7 @@
 pub fn target() -> Target {
     let mut base = super::linux_musl_base::opts();
     base.cpu = "ppc64".to_string();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.max_atomic_width = Some(64);
 
     Target {

compiler/rustc_target/src/spec/powerpc64le_unknown_linux_gnu.rs

@@ -3,7 +3,7 @@
 pub fn target() -> Target {
     let mut base = super::linux_gnu_base::opts();
     base.cpu = "ppc64le".to_string();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.max_atomic_width = Some(64);
 
     Target {

compiler/rustc_target/src/spec/powerpc64le_unknown_linux_musl.rs

@@ -3,7 +3,7 @@
 pub fn target() -> Target {
     let mut base = super::linux_musl_base::opts();
     base.cpu = "ppc64le".to_string();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.max_atomic_width = Some(64);
 
     Target {

compiler/rustc_target/src/spec/powerpc_unknown_linux_gnu.rs

@@ -3,7 +3,7 @@
 
 pub fn target() -> Target {
     let mut base = super::linux_gnu_base::opts();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m32".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m32".to_string());
     base.max_atomic_width = Some(32);
 
     Target {

compiler/rustc_target/src/spec/powerpc_unknown_linux_gnuspe.rs

@@ -3,7 +3,7 @@
 
 pub fn target() -> Target {
     let mut base = super::linux_gnu_base::opts();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-mspe".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-mspe".to_string());
     base.max_atomic_width = Some(32);
 
     Target {

compiler/rustc_target/src/spec/powerpc_unknown_linux_musl.rs

@@ -3,7 +3,7 @@
 
 pub fn target() -> Target {
     let mut base = super::linux_musl_base::opts();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m32".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m32".to_string());
     base.max_atomic_width = Some(32);
 
     Target {

compiler/rustc_target/src/spec/sparc64_unknown_openbsd.rs

@@ -5,7 +5,7 @@ pub fn target() -> Target {
     let mut base = super::openbsd_base::opts();
     base.endian = Endian::Big;
     base.cpu = "v9".to_string();
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.max_atomic_width = Some(64);
 
     Target {

compiler/rustc_target/src/spec/sparc_unknown_linux_gnu.rs

@@ -6,7 +6,7 @@ pub fn target() -> Target {
     base.endian = Endian::Big;
     base.cpu = "v9".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-mv8plus".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-mv8plus".to_string());
 
     Target {
         llvm_target: "sparc-unknown-linux-gnu".to_string(),

compiler/rustc_target/src/spec/thumbv7a_pc_windows_msvc.rs

@@ -11,10 +11,10 @@ pub fn target() -> Target {
     // where necessary, but this is not the observed behavior.
     // Disabling the LBR optimization works around the issue.
     let pre_link_args_msvc = "/OPT:NOLBR".to_string();
-    base.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().push(pre_link_args_msvc.clone());
+    base.pre_link_args.entry(LinkerFlavor::Msvc).or_default().push(pre_link_args_msvc.clone());
     base.pre_link_args
-        .get_mut(&LinkerFlavor::Lld(LldFlavor::Link))
-        .unwrap()
+        .entry(LinkerFlavor::Lld(LldFlavor::Link))
+        .or_default()
         .push(pre_link_args_msvc);
 
     // FIXME(jordanrh): use PanicStrategy::Unwind when SEH is

compiler/rustc_target/src/spec/thumbv7neon_linux_androideabi.rs

@@ -12,7 +12,7 @@ pub fn target() -> Target {
     let mut base = super::android_base::opts();
     base.features = "+v7,+thumb-mode,+thumb2,+vfp3,+neon".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-march=armv7-a".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-march=armv7-a".to_string());
 
     Target {
         llvm_target: "armv7-none-linux-android".to_string(),

compiler/rustc_target/src/spec/uefi_msvc_base.rs

@@ -30,10 +30,10 @@ pub fn opts() -> TargetOptions {
         // exit (default for applications).
         "/subsystem:efi_application".to_string(),
     ];
-    base.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().extend(pre_link_args_msvc.clone());
+    base.pre_link_args.entry(LinkerFlavor::Msvc).or_default().extend(pre_link_args_msvc.clone());
     base.pre_link_args
-        .get_mut(&LinkerFlavor::Lld(LldFlavor::Link))
-        .unwrap()
+        .entry(LinkerFlavor::Lld(LldFlavor::Link))
+        .or_default()
         .extend(pre_link_args_msvc);
 
     TargetOptions {

compiler/rustc_target/src/spec/wasm32_unknown_emscripten.rs

@@ -4,7 +4,7 @@
 pub fn target() -> Target {
     let mut options = wasm32_base::options();
 
-    let clang_args = options.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap();
+    let clang_args = options.pre_link_args.entry(LinkerFlavor::Gcc).or_default();
 
     // Rust really needs a way for users to specify exports and imports in
     // the source code. --export-dynamic isn't the right tool for this job,

compiler/rustc_target/src/spec/wasm32_unknown_unknown.rs

@@ -17,7 +17,7 @@ pub fn target() -> Target {
     let mut options = wasm32_base::options();
     options.os = "unknown".to_string();
     options.linker_flavor = LinkerFlavor::Lld(LldFlavor::Wasm);
-    let clang_args = options.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap();
+    let clang_args = options.pre_link_args.entry(LinkerFlavor::Gcc).or_default();
 
     // Make sure clang uses LLD as its linker and is configured appropriately
     // otherwise
@@ -35,7 +35,7 @@ pub fn target() -> Target {
     clang_args.push("-Wl,--export-dynamic".to_string());
 
     // Add the flags to wasm-ld's args too.
-    let lld_args = options.pre_link_args.get_mut(&LinkerFlavor::Lld(LldFlavor::Wasm)).unwrap();
+    let lld_args = options.pre_link_args.entry(LinkerFlavor::Lld(LldFlavor::Wasm)).or_default();
     lld_args.push("--no-entry".to_string());
     lld_args.push("--export-dynamic".to_string());
 

compiler/rustc_target/src/spec/windows_uwp_msvc_base.rs

@@ -5,10 +5,10 @@ pub fn opts() -> TargetOptions {
 
     opts.vendor = "uwp".to_string();
     let pre_link_args_msvc = vec!["/APPCONTAINER".to_string(), "mincore.lib".to_string()];
-    opts.pre_link_args.get_mut(&LinkerFlavor::Msvc).unwrap().extend(pre_link_args_msvc.clone());
+    opts.pre_link_args.entry(LinkerFlavor::Msvc).or_default().extend(pre_link_args_msvc.clone());
     opts.pre_link_args
-        .get_mut(&LinkerFlavor::Lld(LldFlavor::Link))
-        .unwrap()
+        .entry(LinkerFlavor::Lld(LldFlavor::Link))
+        .or_default()
         .extend(pre_link_args_msvc);
 
     opts

compiler/rustc_target/src/spec/x86_64_linux_android.rs

@@ -6,7 +6,7 @@ pub fn target() -> Target {
     // https://developer.android.com/ndk/guides/abis.html#86-64
     base.features = "+mmx,+sse,+sse2,+sse3,+ssse3,+sse4.1,+sse4.2,+popcnt".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
 
     Target {

compiler/rustc_target/src/spec/x86_64_pc_windows_gnu.rs

@@ -3,7 +3,7 @@
 pub fn target() -> Target {
     let mut base = super::windows_gnu_base::opts();
     base.cpu = "x86-64".to_string();
-    let gcc_pre_link_args = base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap();
+    let gcc_pre_link_args = base.pre_link_args.entry(LinkerFlavor::Gcc).or_default();
     gcc_pre_link_args.push("-m64".to_string());
     // Use high-entropy 64 bit address space for ASLR
     gcc_pre_link_args.push("-Wl,--high-entropy-va".to_string());

compiler/rustc_target/src/spec/x86_64_unknown_dragonfly.rs

@@ -4,7 +4,7 @@ pub fn target() -> Target {
     let mut base = super::dragonfly_base::opts();
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
 
     Target {

compiler/rustc_target/src/spec/x86_64_unknown_freebsd.rs

@@ -4,7 +4,7 @@ pub fn target() -> Target {
     let mut base = super::freebsd_base::opts();
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
 
     Target {

compiler/rustc_target/src/spec/x86_64_unknown_linux_gnu.rs

@@ -4,7 +4,7 @@ pub fn target() -> Target {
     let mut base = super::linux_gnu_base::opts();
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
 
     Target {

compiler/rustc_target/src/spec/x86_64_unknown_linux_gnux32.rs

@@ -4,7 +4,7 @@ pub fn target() -> Target {
     let mut base = super::linux_gnu_base::opts();
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-mx32".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-mx32".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
     base.has_elf_tls = false;
     // BUG(GabrielMajeri): disabling the PLT on x86_64 Linux with x32 ABI

compiler/rustc_target/src/spec/x86_64_unknown_linux_musl.rs

@@ -4,7 +4,7 @@ pub fn target() -> Target {
     let mut base = super::linux_musl_base::opts();
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
     base.static_position_independent_executables = true;
 

compiler/rustc_target/src/spec/x86_64_unknown_none_linuxkernel.rs

@@ -11,7 +11,7 @@ pub fn target() -> Target {
         "-mmx,-sse,-sse2,-sse3,-ssse3,-sse4.1,-sse4.2,-3dnow,-3dnowa,-avx,-avx2,+soft-float"
             .to_string();
     base.code_model = Some(CodeModel::Kernel);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
 
     Target {
         // FIXME: Some dispute, the linux-on-clang folks think this should use

compiler/rustc_target/src/spec/x86_64_unknown_openbsd.rs

@@ -4,7 +4,7 @@ pub fn target() -> Target {
     let mut base = super::openbsd_base::opts();
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
 
     Target {

compiler/rustc_target/src/spec/x86_64_unknown_redox.rs

@@ -4,7 +4,7 @@ pub fn target() -> Target {
     let mut base = super::redox_base::opts();
     base.cpu = "x86-64".to_string();
     base.max_atomic_width = Some(64);
-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+    base.pre_link_args.entry(LinkerFlavor::Gcc).or_default().push("-m64".to_string());
     base.stack_probes = StackProbeType::InlineOrCall { min_llvm_version_for_inline: (11, 0, 1) };
 
     Target {

compiler/rustc_target/src/spec/x86_64_uwp_windows_gnu.rs

@@ -3,7 +3,7 @@
 pub fn target() -> Target {
     let mut base = super::windows_uwp_gnu_base::opts();
     base.cpu = "x86-64".to_string();
-    let gcc_pre_link_args = base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap();
+    let gcc_pre_link_args = base.pre_link_args.entry(LinkerFlavor::Gcc).or_default();
     gcc_pre_link_args.push("-m64".to_string());
     // Use high-entropy 64 bit address space for ASLR
     gcc_pre_link_args.push("-Wl,--high-entropy-va".to_string());