embed riscv64 target abi in bc when plugin-lto is used

Fixes chromium linking error. Related: - https://discourse.llvm.org/t/encode-target-abi-into-llvm-bitcode-for-lto/54116 - https://internals.rust-lang.org/t/per-target-llvm-module-flags/12023
kxxt · Jan 28, 2024 · a599284 · a599284
1 parent 6351247
commit a599284
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Showing 6 changed files with 62 additions and 21 deletions.
diff --git a/compiler/rustc_codegen_llvm/src/back/lto.rs b/compiler/rustc_codegen_llvm/src/back/lto.rs
@@ -607,7 +607,7 @@ pub(crate) fn run_pass_manager(
             "LTOPostLink".as_ptr().cast(),
             11,
         ) {
-            llvm::LLVMRustAddModuleFlag(
+            llvm::LLVMRustAddModuleFlagU32(
                 module.module_llvm.llmod(),
                 llvm::LLVMModFlagBehavior::Error,
                 c"LTOPostLink".as_ptr().cast(),

diff --git a/compiler/rustc_codegen_llvm/src/context.rs b/compiler/rustc_codegen_llvm/src/context.rs
@@ -30,6 +30,7 @@ use rustc_span::Span;
 use rustc_target::abi::{
     call::FnAbi, HasDataLayout, PointeeInfo, Size, TargetDataLayout, VariantIdx,
 };
+use rustc_target::spec::TargetTriple;
 use rustc_target::spec::{HasTargetSpec, RelocModel, Target, TlsModel};
 use smallvec::SmallVec;
 
@@ -203,13 +204,13 @@ pub unsafe fn create_module<'ll>(
     // to ensure intrinsic calls don't use it.
     if !sess.needs_plt() {
         let avoid_plt = c"RtLibUseGOT".as_ptr().cast();
-        llvm::LLVMRustAddModuleFlag(llmod, llvm::LLVMModFlagBehavior::Warning, avoid_plt, 1);
+        llvm::LLVMRustAddModuleFlagU32(llmod, llvm::LLVMModFlagBehavior::Warning, avoid_plt, 1);
     }
 
     // Enable canonical jump tables if CFI is enabled. (See https://reviews.llvm.org/D65629.)
     if sess.is_sanitizer_cfi_canonical_jump_tables_enabled() && sess.is_sanitizer_cfi_enabled() {
         let canonical_jump_tables = c"CFI Canonical Jump Tables".as_ptr().cast();
-        llvm::LLVMRustAddModuleFlag(
+        llvm::LLVMRustAddModuleFlagU32(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
             canonical_jump_tables,
@@ -220,7 +221,7 @@ pub unsafe fn create_module<'ll>(
     // Enable LTO unit splitting if specified or if CFI is enabled. (See https://reviews.llvm.org/D53891.)
     if sess.is_split_lto_unit_enabled() || sess.is_sanitizer_cfi_enabled() {
         let enable_split_lto_unit = c"EnableSplitLTOUnit".as_ptr().cast();
-        llvm::LLVMRustAddModuleFlag(
+        llvm::LLVMRustAddModuleFlagU32(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
             enable_split_lto_unit,
@@ -231,7 +232,7 @@ pub unsafe fn create_module<'ll>(
     // Add "kcfi" module flag if KCFI is enabled. (See https://reviews.llvm.org/D119296.)
     if sess.is_sanitizer_kcfi_enabled() {
         let kcfi = c"kcfi".as_ptr().cast();
-        llvm::LLVMRustAddModuleFlag(llmod, llvm::LLVMModFlagBehavior::Override, kcfi, 1);
+        llvm::LLVMRustAddModuleFlagU32(llmod, llvm::LLVMModFlagBehavior::Override, kcfi, 1);
     }
 
     // Control Flow Guard is currently only supported by the MSVC linker on Windows.
@@ -240,7 +241,7 @@ pub unsafe fn create_module<'ll>(
             CFGuard::Disabled => {}
             CFGuard::NoChecks => {
                 // Set `cfguard=1` module flag to emit metadata only.
-                llvm::LLVMRustAddModuleFlag(
+                llvm::LLVMRustAddModuleFlagU32(
                     llmod,
                     llvm::LLVMModFlagBehavior::Warning,
                     c"cfguard".as_ptr() as *const _,
@@ -249,7 +250,7 @@ pub unsafe fn create_module<'ll>(
             }
             CFGuard::Checks => {
                 // Set `cfguard=2` module flag to emit metadata and checks.
-                llvm::LLVMRustAddModuleFlag(
+                llvm::LLVMRustAddModuleFlagU32(
                     llmod,
                     llvm::LLVMModFlagBehavior::Warning,
                     c"cfguard".as_ptr() as *const _,
@@ -267,26 +268,26 @@ pub unsafe fn create_module<'ll>(
         };
 
         if sess.target.arch == "aarch64" {
-            llvm::LLVMRustAddModuleFlag(
+            llvm::LLVMRustAddModuleFlagU32(
                 llmod,
                 behavior,
                 c"branch-target-enforcement".as_ptr().cast(),
                 bti.into(),
             );
-            llvm::LLVMRustAddModuleFlag(
+            llvm::LLVMRustAddModuleFlagU32(
                 llmod,
                 behavior,
                 c"sign-return-address".as_ptr().cast(),
                 pac_ret.is_some().into(),
             );
             let pac_opts = pac_ret.unwrap_or(PacRet { leaf: false, key: PAuthKey::A });
-            llvm::LLVMRustAddModuleFlag(
+            llvm::LLVMRustAddModuleFlagU32(
                 llmod,
                 behavior,
                 c"sign-return-address-all".as_ptr().cast(),
                 pac_opts.leaf.into(),
             );
-            llvm::LLVMRustAddModuleFlag(
+            llvm::LLVMRustAddModuleFlagU32(
                 llmod,
                 behavior,
                 c"sign-return-address-with-bkey".as_ptr().cast(),
@@ -302,15 +303,15 @@ pub unsafe fn create_module<'ll>(
 
     // Pass on the control-flow protection flags to LLVM (equivalent to `-fcf-protection` in Clang).
     if let CFProtection::Branch | CFProtection::Full = sess.opts.unstable_opts.cf_protection {
-        llvm::LLVMRustAddModuleFlag(
+        llvm::LLVMRustAddModuleFlagU32(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
             c"cf-protection-branch".as_ptr().cast(),
             1,
         )
     }
     if let CFProtection::Return | CFProtection::Full = sess.opts.unstable_opts.cf_protection {
-        llvm::LLVMRustAddModuleFlag(
+        llvm::LLVMRustAddModuleFlagU32(
             llmod,
             llvm::LLVMModFlagBehavior::Override,
             c"cf-protection-return".as_ptr().cast(),
@@ -319,7 +320,7 @@ pub unsafe fn create_module<'ll>(
     }
 
     if sess.opts.unstable_opts.virtual_function_elimination {
-        llvm::LLVMRustAddModuleFlag(
+        llvm::LLVMRustAddModuleFlagU32(
             llmod,
             llvm::LLVMModFlagBehavior::Error,
             c"Virtual Function Elim".as_ptr().cast(),
@@ -329,7 +330,7 @@ pub unsafe fn create_module<'ll>(
 
     // Set module flag to enable Windows EHCont Guard (/guard:ehcont).
     if sess.opts.unstable_opts.ehcont_guard {
-        llvm::LLVMRustAddModuleFlag(
+        llvm::LLVMRustAddModuleFlagU32(
             llmod,
             llvm::LLVMModFlagBehavior::Warning,
             c"ehcontguard".as_ptr() as *const _,
@@ -354,6 +355,24 @@ pub unsafe fn create_module<'ll>(
         llvm::LLVMMDNodeInContext(llcx, &name_metadata, 1),
     );
 
+    // Embed target-abi into bitcode for rv64gc when plugin-lto is enabled
+    // Relevant:
+    // https://discourse.llvm.org/t/encode-target-abi-into-llvm-bitcode-for-lto/54116
+    // https://internals.rust-lang.org/t/per-target-llvm-module-flags/12023
+    if sess.opts.cg.linker_plugin_lto.enabled() {
+        let TargetTriple::TargetTriple(ref triple) = sess.opts.target_triple else {
+            panic!("Unexpected TargetTriple::TargetJson")
+        };
+        if triple == "riscv64gc-unknown-linux-gnu" {
+            llvm::LLVMRustAddModuleFlagString(
+                llmod,
+                llvm::LLVMModFlagBehavior::Error,
+                c"target-abi".as_ptr() as *const _,
+                c"lp64d".as_ptr() as *const _,
+            )
+        }
+    }
+
     // Add module flags specified via -Z llvm_module_flag
     for (key, value, behavior) in &sess.opts.unstable_opts.llvm_module_flag {
         let key = format!("{key}\0");
@@ -369,7 +388,7 @@ pub unsafe fn create_module<'ll>(
             // We already checked this during option parsing
             _ => unreachable!(),
         };
-        llvm::LLVMRustAddModuleFlag(llmod, behavior, key.as_ptr().cast(), *value)
+        llvm::LLVMRustAddModuleFlagU32(llmod, behavior, key.as_ptr().cast(), *value)
     }
 
     llmod

diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
@@ -110,15 +110,15 @@ impl<'ll, 'tcx> CodegenUnitDebugContext<'ll, 'tcx> {
                     .unstable_opts
                     .dwarf_version
                     .unwrap_or(sess.target.default_dwarf_version);
-                llvm::LLVMRustAddModuleFlag(
+                llvm::LLVMRustAddModuleFlagU32(
                     self.llmod,
                     llvm::LLVMModFlagBehavior::Warning,
                     c"Dwarf Version".as_ptr().cast(),
                     dwarf_version,
                 );
             } else {
                 // Indicate that we want CodeView debug information on MSVC
-                llvm::LLVMRustAddModuleFlag(
+                llvm::LLVMRustAddModuleFlagU32(
                     self.llmod,
                     llvm::LLVMModFlagBehavior::Warning,
                     c"CodeView".as_ptr().cast(),
@@ -127,7 +127,7 @@ impl<'ll, 'tcx> CodegenUnitDebugContext<'ll, 'tcx> {
             }
 
             // Prevent bitcode readers from deleting the debug info.
-            llvm::LLVMRustAddModuleFlag(
+            llvm::LLVMRustAddModuleFlagU32(
                 self.llmod,
                 llvm::LLVMModFlagBehavior::Warning,
                 c"Debug Info Version".as_ptr().cast(),

diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -1793,12 +1793,20 @@ extern "C" {
     ///
     /// In order for Rust-C LTO to work, module flags must be compatible with Clang. What
     /// "compatible" means depends on the merge behaviors involved.
-    pub fn LLVMRustAddModuleFlag(
+    pub fn LLVMRustAddModuleFlagU32(
         M: &Module,
         merge_behavior: LLVMModFlagBehavior,
         name: *const c_char,
         value: u32,
     );
+
+    pub fn LLVMRustAddModuleFlagString(
+        M: &Module,
+        merge_behavior: LLVMModFlagBehavior,
+        name: *const c_char,
+        value: *const c_char,
+    );
+
     pub fn LLVMRustHasModuleFlag(M: &Module, name: *const c_char, len: size_t) -> bool;
 
     pub fn LLVMRustDIBuilderCreate(M: &Module) -> &mut DIBuilder<'_>;

diff --git a/compiler/rustc_codegen_llvm/src/llvm/mod.rs b/compiler/rustc_codegen_llvm/src/llvm/mod.rs
@@ -324,3 +324,8 @@ impl Drop for OperandBundleDef<'_> {
         }
     }
 }
+
+pub enum LLVMModFlagValue {
+    String(String),
+    U32(u32),
+}
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -748,14 +748,23 @@ extern "C" uint32_t LLVMRustVersionMinor() { return LLVM_VERSION_MINOR; }
 
 extern "C" uint32_t LLVMRustVersionMajor() { return LLVM_VERSION_MAJOR; }
 
-extern "C" void LLVMRustAddModuleFlag(
+extern "C" void LLVMRustAddModuleFlagU32(
     LLVMModuleRef M,
     Module::ModFlagBehavior MergeBehavior,
     const char *Name,
     uint32_t Value) {
   unwrap(M)->addModuleFlag(MergeBehavior, Name, Value);
 }
 
+extern "C" void LLVMRustAddModuleFlagString(
+    LLVMModuleRef M,
+    Module::ModFlagBehavior MergeBehavior,
+    const char *Name,
+    const char *Value) {
+  llvm::LLVMContext &Ctx = unwrap(M)->getContext();
+  unwrap(M)->addModuleFlag(MergeBehavior, Name, llvm::MDString::get(Ctx, Value));
+}
+
 extern "C" bool LLVMRustHasModuleFlag(LLVMModuleRef M, const char *Name,
                                       size_t Len) {
   return unwrap(M)->getModuleFlag(StringRef(Name, Len)) != nullptr;