b846b42c8d
Add `no_sanitize` attribute that allows to opt out from sanitizer instrumentation in an annotated function.
97 lines
3.4 KiB
Rust
97 lines
3.4 KiB
Rust
//! Declare various LLVM values.
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//!
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//! Prefer using functions and methods from this module rather than calling LLVM
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//! functions directly. These functions do some additional work to ensure we do
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//! the right thing given the preconceptions of codegen.
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//!
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//! Some useful guidelines:
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//!
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//! * Use declare_* family of methods if you are declaring, but are not
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//! interested in defining the Value they return.
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//! * Use define_* family of methods when you might be defining the Value.
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//! * When in doubt, define.
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use crate::abi::{FnAbi, FnAbiLlvmExt};
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use crate::attributes;
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use crate::context::CodegenCx;
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use crate::llvm;
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use crate::llvm::AttributePlace::Function;
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use crate::type_::Type;
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use crate::value::Value;
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use log::debug;
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use rustc::ty::Ty;
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use rustc_codegen_ssa::traits::*;
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use rustc_data_structures::small_c_str::SmallCStr;
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/// Declare a function.
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///
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/// If there’s a value with the same name already declared, the function will
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/// update the declaration and return existing Value instead.
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fn declare_raw_fn(
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cx: &CodegenCx<'ll, '_>,
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name: &str,
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callconv: llvm::CallConv,
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ty: &'ll Type,
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) -> &'ll Value {
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debug!("declare_raw_fn(name={:?}, ty={:?})", name, ty);
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let namebuf = SmallCStr::new(name);
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let llfn = unsafe { llvm::LLVMRustGetOrInsertFunction(cx.llmod, namebuf.as_ptr(), ty) };
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llvm::SetFunctionCallConv(llfn, callconv);
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// Function addresses in Rust are never significant, allowing functions to
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// be merged.
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llvm::SetUnnamedAddr(llfn, true);
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if cx.tcx.sess.opts.cg.no_redzone.unwrap_or(cx.tcx.sess.target.target.options.disable_redzone) {
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llvm::Attribute::NoRedZone.apply_llfn(Function, llfn);
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}
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attributes::default_optimisation_attrs(cx.tcx.sess, llfn);
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attributes::non_lazy_bind(cx.sess(), llfn);
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llfn
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}
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impl DeclareMethods<'tcx> for CodegenCx<'ll, 'tcx> {
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fn declare_global(&self, name: &str, ty: &'ll Type) -> &'ll Value {
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debug!("declare_global(name={:?})", name);
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unsafe { llvm::LLVMRustGetOrInsertGlobal(self.llmod, name.as_ptr().cast(), name.len(), ty) }
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}
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fn declare_cfn(&self, name: &str, fn_type: &'ll Type) -> &'ll Value {
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declare_raw_fn(self, name, llvm::CCallConv, fn_type)
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}
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fn declare_fn(&self, name: &str, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> &'ll Value {
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debug!("declare_rust_fn(name={:?}, fn_abi={:?})", name, fn_abi);
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let llfn = declare_raw_fn(self, name, fn_abi.llvm_cconv(), fn_abi.llvm_type(self));
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fn_abi.apply_attrs_llfn(self, llfn);
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llfn
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}
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fn define_global(&self, name: &str, ty: &'ll Type) -> Option<&'ll Value> {
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if self.get_defined_value(name).is_some() {
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None
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} else {
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Some(self.declare_global(name, ty))
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}
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}
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fn define_private_global(&self, ty: &'ll Type) -> &'ll Value {
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unsafe { llvm::LLVMRustInsertPrivateGlobal(self.llmod, ty) }
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}
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fn get_declared_value(&self, name: &str) -> Option<&'ll Value> {
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debug!("get_declared_value(name={:?})", name);
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let namebuf = SmallCStr::new(name);
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unsafe { llvm::LLVMRustGetNamedValue(self.llmod, namebuf.as_ptr()) }
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}
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fn get_defined_value(&self, name: &str) -> Option<&'ll Value> {
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self.get_declared_value(name).and_then(|val| {
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let declaration = unsafe { llvm::LLVMIsDeclaration(val) != 0 };
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if !declaration { Some(val) } else { None }
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})
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}
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}
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