Remove bitcode_llvm_cmdline

It used to be necessary on Apple platforms to ship with the App Store,
but XCode 15 has stopped embedding LLVM bitcode and the App Store no
longer accepts apps with bitcode embedded.

Author: bjorn3

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -862,7 +862,7 @@ pub(crate) fn codegen(
                     .generic_activity_with_arg("LLVM_module_codegen_embed_bitcode", &*module.name);
                 let thin_bc =
                     module.thin_lto_buffer.as_deref().expect("cannot find embedded bitcode");
-                embed_bitcode(cgcx, llcx, llmod, &config.bc_cmdline, &thin_bc);
+                embed_bitcode(cgcx, llcx, llmod, &thin_bc);
             }
         }
 
@@ -1058,40 +1058,38 @@ fn embed_bitcode(
     cgcx: &CodegenContext<LlvmCodegenBackend>,
     llcx: &llvm::Context,
     llmod: &llvm::Module,
-    cmdline: &str,
     bitcode: &[u8],
 ) {
     // We're adding custom sections to the output object file, but we definitely
     // do not want these custom sections to make their way into the final linked
-    // executable. The purpose of these custom sections is for tooling
-    // surrounding object files to work with the LLVM IR, if necessary. For
-    // example rustc's own LTO will look for LLVM IR inside of the object file
-    // in these sections by default.
+    // executable. The purpose of this custom section is for tooling surrounding
+    // object files to work with the LLVM IR, if necessary. For example rustc's
+    // own LTO will look for LLVM IR inside of the object file in this section
+    // by default.
     //
     // To handle this is a bit different depending on the object file format
     // used by the backend, broken down into a few different categories:
     //
     // * Mach-O - this is for macOS. Inspecting the source code for the native
-    //   linker here shows that the `.llvmbc` and `.llvmcmd` sections are
-    //   automatically skipped by the linker. In that case there's nothing extra
-    //   that we need to do here.
+    //   linker here shows that the `.llvmbc` section is automatically skipped
+    //   by the linker. In that case there's nothing extra that we need to do
+    //   here.
     //
-    // * Wasm - the native LLD linker is hard-coded to skip `.llvmbc` and
-    //   `.llvmcmd` sections, so there's nothing extra we need to do.
+    // * Wasm - the native LLD linker is hard-coded to skip `.llvmbc` section,
+    //   so there's nothing extra we need to do.
     //
-    // * COFF - if we don't do anything the linker will by default copy all
-    //   these sections to the output artifact, not what we want! To subvert
-    //   this we want to flag the sections we inserted here as
-    //   `IMAGE_SCN_LNK_REMOVE`.
+    // * COFF - if we don't do anything the linker will by default copy this
+    //   section to the output artifact, not what we want! To subvert this we
+    //   want to flag the section we inserted here as `IMAGE_SCN_LNK_REMOVE`.
     //
-    // * ELF - this is very similar to COFF above. One difference is that these
-    //   sections are removed from the output linked artifact when
-    //   `--gc-sections` is passed, which we pass by default. If that flag isn't
-    //   passed though then these sections will show up in the final output.
-    //   Additionally the flag that we need to set here is `SHF_EXCLUDE`.
+    // * ELF - this is very similar to COFF above. One difference is that this
+    //   section is removed from the output linked artifact when `--gc-sections`
+    //   is passed, which we pass by default. If that flag isn't passed through
+    //   then this section will show up in the final output. Additionally the
+    //   flag that we need to set here is `SHF_EXCLUDE`.
     //
-    // * XCOFF - AIX linker ignores content in .ipa and .info if no auxiliary
-    //   symbol associated with these sections.
+    // * XCOFF - AIX linker ignores content in .ipa if no auxiliary symbol
+    //   associated with this section.
     //
     // Unfortunately, LLVM provides no way to set custom section flags. For ELF
     // and COFF we emit the sections using module level inline assembly for that
@@ -1110,26 +1108,11 @@ fn embed_bitcode(
         llvm::set_section(llglobal, bitcode_section_name(cgcx));
         llvm::set_linkage(llglobal, llvm::Linkage::PrivateLinkage);
         llvm::LLVMSetGlobalConstant(llglobal, llvm::True);
-
-        let llconst = common::bytes_in_context(llcx, cmdline.as_bytes());
-        let llglobal = llvm::add_global(llmod, common::val_ty(llconst), c"rustc.embedded.cmdline");
-        llvm::set_initializer(llglobal, llconst);
-        let section = if cgcx.target_is_like_darwin {
-            c"__LLVM,__cmdline"
-        } else if cgcx.target_is_like_aix {
-            c".info"
-        } else {
-            c".llvmcmd"
-        };
-        llvm::set_section(llglobal, section);
-        llvm::set_linkage(llglobal, llvm::Linkage::PrivateLinkage);
     } else {
         // We need custom section flags, so emit module-level inline assembly.
         let section_flags = if cgcx.is_pe_coff { "n" } else { "e" };
         let asm = create_section_with_flags_asm(".llvmbc", section_flags, bitcode);
         llvm::append_module_inline_asm(llmod, &asm);
-        let asm = create_section_with_flags_asm(".llvmcmd", section_flags, cmdline.as_bytes());
-        llvm::append_module_inline_asm(llmod, &asm);
     }
 }
 

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -99,7 +99,6 @@ pub struct ModuleConfig {
     pub emit_obj: EmitObj,
     pub emit_thin_lto: bool,
     pub emit_thin_lto_summary: bool,
-    pub bc_cmdline: String,
 
     // Miscellaneous flags. These are mostly copied from command-line
     // options.
@@ -216,7 +215,6 @@ impl ModuleConfig {
                 sess.opts.output_types.contains_key(&OutputType::ThinLinkBitcode),
                 false
             ),
-            bc_cmdline: sess.target.bitcode_llvm_cmdline.to_string(),
 
             verify_llvm_ir: sess.verify_llvm_ir(),
             lint_llvm_ir: sess.opts.unstable_opts.lint_llvm_ir,

compiler/rustc_target/src/spec/json.rs

@@ -167,7 +167,6 @@ impl Target {
         forward!(main_needs_argc_argv);
         forward!(has_thread_local);
         forward!(obj_is_bitcode);
-        forward!(bitcode_llvm_cmdline);
         forward_opt!(max_atomic_width);
         forward_opt!(min_atomic_width);
         forward!(atomic_cas);
@@ -359,7 +358,6 @@ impl ToJson for Target {
         target_option_val!(main_needs_argc_argv);
         target_option_val!(has_thread_local);
         target_option_val!(obj_is_bitcode);
-        target_option_val!(bitcode_llvm_cmdline);
         target_option_val!(min_atomic_width);
         target_option_val!(max_atomic_width);
         target_option_val!(atomic_cas);
@@ -552,7 +550,6 @@ struct TargetSpecJson {
     main_needs_argc_argv: Option<bool>,
     has_thread_local: Option<bool>,
     obj_is_bitcode: Option<bool>,
-    bitcode_llvm_cmdline: Option<StaticCow<str>>,
     max_atomic_width: Option<u64>,
     min_atomic_width: Option<u64>,
     atomic_cas: Option<bool>,

compiler/rustc_target/src/spec/mod.rs

@@ -2620,8 +2620,6 @@ pub struct TargetOptions {
     /// If we give emcc .o files that are actually .bc files it
     /// will 'just work'.
     pub obj_is_bitcode: bool,
-    /// Content of the LLVM cmdline section associated with embedded bitcode.
-    pub bitcode_llvm_cmdline: StaticCow<str>,
 
     /// Don't use this field; instead use the `.min_atomic_width()` method.
     pub min_atomic_width: Option<u64>,
@@ -2984,7 +2982,6 @@ impl Default for TargetOptions {
             allow_asm: true,
             has_thread_local: false,
             obj_is_bitcode: false,
-            bitcode_llvm_cmdline: "".into(),
             min_atomic_width: None,
             max_atomic_width: None,
             atomic_cas: true,