1 files changed, 173 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_llvm/src/base.rs b/compiler/rustc_codegen_llvm/src/base.rs
new file mode 100644
index 000000000..86f92dc02
--- /dev/null
+++ b/compiler/rustc_codegen_llvm/src/base.rs
@@ -0,0 +1,173 @@
+//! Codegen the MIR to the LLVM IR.
+//!
+//! Hopefully useful general knowledge about codegen:
+//!
+//! * There's no way to find out the [`Ty`] type of a [`Value`]. Doing so
+//!   would be "trying to get the eggs out of an omelette" (credit:
+//!   pcwalton). You can, instead, find out its [`llvm::Type`] by calling [`val_ty`],
+//!   but one [`llvm::Type`] corresponds to many [`Ty`]s; for instance, `tup(int, int,
+//!   int)` and `rec(x=int, y=int, z=int)` will have the same [`llvm::Type`].
+//!
+//! [`Ty`]: rustc_middle::ty::Ty
+//! [`val_ty`]: crate::common::val_ty
+
+use super::ModuleLlvm;
+
+use crate::attributes;
+use crate::builder::Builder;
+use crate::context::CodegenCx;
+use crate::llvm;
+use crate::value::Value;
+
+use rustc_codegen_ssa::base::maybe_create_entry_wrapper;
+use rustc_codegen_ssa::mono_item::MonoItemExt;
+use rustc_codegen_ssa::traits::*;
+use rustc_codegen_ssa::{ModuleCodegen, ModuleKind};
+use rustc_data_structures::small_c_str::SmallCStr;
+use rustc_middle::dep_graph;
+use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs;
+use rustc_middle::mir::mono::{Linkage, Visibility};
+use rustc_middle::ty::TyCtxt;
+use rustc_session::config::DebugInfo;
+use rustc_span::symbol::Symbol;
+use rustc_target::spec::SanitizerSet;
+
+use std::time::Instant;
+
+pub struct ValueIter<'ll> {
+    cur: Option<&'ll Value>,
+    step: unsafe extern "C" fn(&'ll Value) -> Option<&'ll Value>,
+}
+
+impl<'ll> Iterator for ValueIter<'ll> {
+    type Item = &'ll Value;
+
+    fn next(&mut self) -> Option<&'ll Value> {
+        let old = self.cur;
+        if let Some(old) = old {
+            self.cur = unsafe { (self.step)(old) };
+        }
+        old
+    }
+}
+
+pub fn iter_globals(llmod: &llvm::Module) -> ValueIter<'_> {
+    unsafe { ValueIter { cur: llvm::LLVMGetFirstGlobal(llmod), step: llvm::LLVMGetNextGlobal } }
+}
+
+pub fn compile_codegen_unit(tcx: TyCtxt<'_>, cgu_name: Symbol) -> (ModuleCodegen<ModuleLlvm>, u64) {
+    let start_time = Instant::now();
+
+    let dep_node = tcx.codegen_unit(cgu_name).codegen_dep_node(tcx);
+    let (module, _) = tcx.dep_graph.with_task(
+        dep_node,
+        tcx,
+        cgu_name,
+        module_codegen,
+        Some(dep_graph::hash_result),
+    );
+    let time_to_codegen = start_time.elapsed();
+
+    // We assume that the cost to run LLVM on a CGU is proportional to
+    // the time we needed for codegenning it.
+    let cost = time_to_codegen.as_nanos() as u64;
+
+    fn module_codegen(tcx: TyCtxt<'_>, cgu_name: Symbol) -> ModuleCodegen<ModuleLlvm> {
+        let cgu = tcx.codegen_unit(cgu_name);
+        let _prof_timer =
+            tcx.prof.generic_activity_with_arg_recorder("codegen_module", |recorder| {
+                recorder.record_arg(cgu_name.to_string());
+                recorder.record_arg(cgu.size_estimate().to_string());
+            });
+        // Instantiate monomorphizations without filling out definitions yet...
+        let llvm_module = ModuleLlvm::new(tcx, cgu_name.as_str());
+        {
+            let cx = CodegenCx::new(tcx, cgu, &llvm_module);
+            let mono_items = cx.codegen_unit.items_in_deterministic_order(cx.tcx);
+            for &(mono_item, (linkage, visibility)) in &mono_items {
+                mono_item.predefine::<Builder<'_, '_, '_>>(&cx, linkage, visibility);
+            }
+
+            // ... and now that we have everything pre-defined, fill out those definitions.
+            for &(mono_item, _) in &mono_items {
+                mono_item.define::<Builder<'_, '_, '_>>(&cx);
+            }
+
+            // If this codegen unit contains the main function, also create the
+            // wrapper here
+            if let Some(entry) = maybe_create_entry_wrapper::<Builder<'_, '_, '_>>(&cx) {
+                let attrs = attributes::sanitize_attrs(&cx, SanitizerSet::empty());
+                attributes::apply_to_llfn(entry, llvm::AttributePlace::Function, &attrs);
+            }
+
+            // Finalize code coverage by injecting the coverage map. Note, the coverage map will
+            // also be added to the `llvm.compiler.used` variable, created next.
+            if cx.sess().instrument_coverage() {
+                cx.coverageinfo_finalize();
+            }
+
+            // Create the llvm.used and llvm.compiler.used variables.
+            if !cx.used_statics().borrow().is_empty() {
+                cx.create_used_variable()
+            }
+            if !cx.compiler_used_statics().borrow().is_empty() {
+                cx.create_compiler_used_variable()
+            }
+
+            // Run replace-all-uses-with for statics that need it. This must
+            // happen after the llvm.used variables are created.
+            for &(old_g, new_g) in cx.statics_to_rauw().borrow().iter() {
+                unsafe {
+                    let bitcast = llvm::LLVMConstPointerCast(new_g, cx.val_ty(old_g));
+                    llvm::LLVMReplaceAllUsesWith(old_g, bitcast);
+                    llvm::LLVMDeleteGlobal(old_g);
+                }
+            }
+
+            // Finalize debuginfo
+            if cx.sess().opts.debuginfo != DebugInfo::None {
+                cx.debuginfo_finalize();
+            }
+        }
+
+        ModuleCodegen {
+            name: cgu_name.to_string(),
+            module_llvm: llvm_module,
+            kind: ModuleKind::Regular,
+        }
+    }
+
+    (module, cost)
+}
+
+pub fn set_link_section(llval: &Value, attrs: &CodegenFnAttrs) {
+    let Some(sect) = attrs.link_section else { return };
+    unsafe {
+        let buf = SmallCStr::new(sect.as_str());
+        llvm::LLVMSetSection(llval, buf.as_ptr());
+    }
+}
+
+pub fn linkage_to_llvm(linkage: Linkage) -> llvm::Linkage {
+    match linkage {
+        Linkage::External => llvm::Linkage::ExternalLinkage,
+        Linkage::AvailableExternally => llvm::Linkage::AvailableExternallyLinkage,
+        Linkage::LinkOnceAny => llvm::Linkage::LinkOnceAnyLinkage,
+        Linkage::LinkOnceODR => llvm::Linkage::LinkOnceODRLinkage,
+        Linkage::WeakAny => llvm::Linkage::WeakAnyLinkage,
+        Linkage::WeakODR => llvm::Linkage::WeakODRLinkage,
+        Linkage::Appending => llvm::Linkage::AppendingLinkage,
+        Linkage::Internal => llvm::Linkage::InternalLinkage,
+        Linkage::Private => llvm::Linkage::PrivateLinkage,
+        Linkage::ExternalWeak => llvm::Linkage::ExternalWeakLinkage,
+        Linkage::Common => llvm::Linkage::CommonLinkage,
+    }
+}
+
+pub fn visibility_to_llvm(linkage: Visibility) -> llvm::Visibility {
+    match linkage {
+        Visibility::Default => llvm::Visibility::Default,
+        Visibility::Hidden => llvm::Visibility::Hidden,
+        Visibility::Protected => llvm::Visibility::Protected,
+    }
+}