mv compiler to compiler/

compiler/rustc_codegen_llvm/src/declare.rs

@@ -0,0 +1,95 @@
+//! Declare various LLVM values.
+//!
+//! Prefer using functions and methods from this module rather than calling LLVM
+//! functions directly. These functions do some additional work to ensure we do
+//! the right thing given the preconceptions of codegen.
+//!
+//! Some useful guidelines:
+//!
+//! * Use declare_* family of methods if you are declaring, but are not
+//!   interested in defining the Value they return.
+//! * Use define_* family of methods when you might be defining the Value.
+//! * When in doubt, define.
+
+use crate::abi::{FnAbi, FnAbiLlvmExt};
+use crate::attributes;
+use crate::context::CodegenCx;
+use crate::llvm;
+use crate::llvm::AttributePlace::Function;
+use crate::type_::Type;
+use crate::value::Value;
+use rustc_codegen_ssa::traits::*;
+use rustc_middle::ty::Ty;
+use tracing::debug;
+
+/// Declare a function.
+///
+/// If there’s a value with the same name already declared, the function will
+/// update the declaration and return existing Value instead.
+fn declare_raw_fn(
+    cx: &CodegenCx<'ll, '_>,
+    name: &str,
+    callconv: llvm::CallConv,
+    ty: &'ll Type,
+) -> &'ll Value {
+    debug!("declare_raw_fn(name={:?}, ty={:?})", name, ty);
+    let llfn = unsafe {
+        llvm::LLVMRustGetOrInsertFunction(cx.llmod, name.as_ptr().cast(), name.len(), ty)
+    };
+
+    llvm::SetFunctionCallConv(llfn, callconv);
+    // Function addresses in Rust are never significant, allowing functions to
+    // be merged.
+    llvm::SetUnnamedAddress(llfn, llvm::UnnamedAddr::Global);
+
+    if cx.tcx.sess.opts.cg.no_redzone.unwrap_or(cx.tcx.sess.target.target.options.disable_redzone) {
+        llvm::Attribute::NoRedZone.apply_llfn(Function, llfn);
+    }
+
+    attributes::default_optimisation_attrs(cx.tcx.sess, llfn);
+    attributes::non_lazy_bind(cx.sess(), llfn);
+    llfn
+}
+
+impl DeclareMethods<'tcx> for CodegenCx<'ll, 'tcx> {
+    fn declare_global(&self, name: &str, ty: &'ll Type) -> &'ll Value {
+        debug!("declare_global(name={:?})", name);
+        unsafe { llvm::LLVMRustGetOrInsertGlobal(self.llmod, name.as_ptr().cast(), name.len(), ty) }
+    }
+
+    fn declare_cfn(&self, name: &str, fn_type: &'ll Type) -> &'ll Value {
+        declare_raw_fn(self, name, llvm::CCallConv, fn_type)
+    }
+
+    fn declare_fn(&self, name: &str, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> &'ll Value {
+        debug!("declare_rust_fn(name={:?}, fn_abi={:?})", name, fn_abi);
+
+        let llfn = declare_raw_fn(self, name, fn_abi.llvm_cconv(), fn_abi.llvm_type(self));
+        fn_abi.apply_attrs_llfn(self, llfn);
+        llfn
+    }
+
+    fn define_global(&self, name: &str, ty: &'ll Type) -> Option<&'ll Value> {
+        if self.get_defined_value(name).is_some() {
+            None
+        } else {
+            Some(self.declare_global(name, ty))
+        }
+    }
+
+    fn define_private_global(&self, ty: &'ll Type) -> &'ll Value {
+        unsafe { llvm::LLVMRustInsertPrivateGlobal(self.llmod, ty) }
+    }
+
+    fn get_declared_value(&self, name: &str) -> Option<&'ll Value> {
+        debug!("get_declared_value(name={:?})", name);
+        unsafe { llvm::LLVMRustGetNamedValue(self.llmod, name.as_ptr().cast(), name.len()) }
+    }
+
+    fn get_defined_value(&self, name: &str) -> Option<&'ll Value> {
+        self.get_declared_value(name).and_then(|val| {
+            let declaration = unsafe { llvm::LLVMIsDeclaration(val) != 0 };
+            if !declaration { Some(val) } else { None }
+        })
+    }
+}