mv compiler to compiler/

compiler/rustc_codegen_llvm/src/base.rs

@@ -0,0 +1,205 @@
+//! Codegen the completed AST to the LLVM IR.
+//!
+//! Some functions here, such as codegen_block and codegen_expr, return a value --
+//! the result of the codegen to LLVM -- while others, such as codegen_fn
+//! and mono_item, are called only for the side effect of adding a
+//! particular definition to the LLVM IR output we're producing.
+//!
+//! 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`.
+
+use super::ModuleLlvm;
+
+use crate::attributes;
+use crate::builder::Builder;
+use crate::common;
+use crate::context::CodegenCx;
+use crate::llvm;
+use crate::metadata;
+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::middle::cstore::EncodedMetadata;
+use rustc_middle::middle::exported_symbols;
+use rustc_middle::mir::mono::{Linkage, Visibility};
+use rustc_middle::ty::TyCtxt;
+use rustc_session::config::{DebugInfo, SanitizerSet};
+use rustc_span::symbol::Symbol;
+
+use std::ffi::CString;
+use std::time::Instant;
+
+pub fn write_compressed_metadata<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    metadata: &EncodedMetadata,
+    llvm_module: &mut ModuleLlvm,
+) {
+    use snap::write::FrameEncoder;
+    use std::io::Write;
+
+    let (metadata_llcx, metadata_llmod) = (&*llvm_module.llcx, llvm_module.llmod());
+    let mut compressed = tcx.metadata_encoding_version();
+    FrameEncoder::new(&mut compressed).write_all(&metadata.raw_data).unwrap();
+
+    let llmeta = common::bytes_in_context(metadata_llcx, &compressed);
+    let llconst = common::struct_in_context(metadata_llcx, &[llmeta], false);
+    let name = exported_symbols::metadata_symbol_name(tcx);
+    let buf = CString::new(name).unwrap();
+    let llglobal =
+        unsafe { llvm::LLVMAddGlobal(metadata_llmod, common::val_ty(llconst), buf.as_ptr()) };
+    unsafe {
+        llvm::LLVMSetInitializer(llglobal, llconst);
+        let section_name = metadata::metadata_section_name(&tcx.sess.target.target);
+        let name = SmallCStr::new(section_name);
+        llvm::LLVMSetSection(llglobal, name.as_ptr());
+
+        // Also generate a .section directive to force no
+        // flags, at least for ELF outputs, so that the
+        // metadata doesn't get loaded into memory.
+        let directive = format!(".section {}", section_name);
+        llvm::LLVMSetModuleInlineAsm2(metadata_llmod, directive.as_ptr().cast(), directive.len())
+    }
+}
+
+pub struct ValueIter<'ll> {
+    cur: Option<&'ll Value>,
+    step: unsafe extern "C" fn(&'ll Value) -> Option<&'ll Value>,
+}
+
+impl 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: &'ll llvm::Module) -> ValueIter<'ll> {
+    unsafe { ValueIter { cur: llvm::LLVMGetFirstGlobal(llmod), step: llvm::LLVMGetNextGlobal } }
+}
+
+pub fn compile_codegen_unit(
+    tcx: TyCtxt<'tcx>,
+    cgu_name: Symbol,
+) -> (ModuleCodegen<ModuleLlvm>, u64) {
+    let prof_timer = tcx.prof.generic_activity_with_arg("codegen_module", cgu_name.to_string());
+    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, dep_graph::hash_result);
+    let time_to_codegen = start_time.elapsed();
+    drop(prof_timer);
+
+    // 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_secs() * 1_000_000_000 + time_to_codegen.subsec_nanos() as u64;
+
+    fn module_codegen(tcx: TyCtxt<'_>, cgu_name: Symbol) -> ModuleCodegen<ModuleLlvm> {
+        let cgu = tcx.codegen_unit(cgu_name);
+        // 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) {
+                attributes::sanitize(&cx, SanitizerSet::empty(), entry);
+            }
+
+            // Run replace-all-uses-with for statics that need it
+            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 code coverage by injecting the coverage map. Note, the coverage map will
+            // also be added to the `llvm.used` variable, created next.
+            if cx.sess().opts.debugging_opts.instrument_coverage {
+                cx.coverageinfo_finalize();
+            }
+
+            // Create the llvm.used variable
+            // This variable has type [N x i8*] and is stored in the llvm.metadata section
+            if !cx.used_statics().borrow().is_empty() {
+                cx.create_used_variable()
+            }
+
+            // 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 sect = match attrs.link_section {
+        Some(name) => name,
+        None => 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,
+    }
+}