rust/src/librustc_trans/trans/debuginfo/gdb.rs
2015-04-29 17:23:36 +12:00

95 lines
3.7 KiB
Rust

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://!rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://!www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://!opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// .debug_gdb_scripts binary section
use llvm;
use llvm::ValueRef;
use trans::common::{C_bytes, CrateContext};
use trans::declare;
use trans::type_::Type;
use middle::ty::ClosureTyper;
use session::config::NoDebugInfo;
use std::ffi::CString;
use std::ptr;
use syntax::attr;
/// Inserts a side-effect free instruction sequence that makes sure that the
/// .debug_gdb_scripts global is referenced, so it isn't removed by the linker.
pub fn insert_reference_to_gdb_debug_scripts_section_global(ccx: &CrateContext) {
if needs_gdb_debug_scripts_section(ccx) {
let empty = CString::new("").unwrap();
let gdb_debug_scripts_section_global =
get_or_insert_gdb_debug_scripts_section_global(ccx);
unsafe {
let volative_load_instruction =
llvm::LLVMBuildLoad(ccx.raw_builder(),
gdb_debug_scripts_section_global,
empty.as_ptr());
llvm::LLVMSetVolatile(volative_load_instruction, llvm::True);
}
}
}
/// Allocates the global variable responsible for the .debug_gdb_scripts binary
/// section.
pub fn get_or_insert_gdb_debug_scripts_section_global(ccx: &CrateContext)
-> llvm::ValueRef {
let section_var_name = "__rustc_debug_gdb_scripts_section__";
let section_var = unsafe {
llvm::LLVMGetNamedGlobal(ccx.llmod(),
section_var_name.as_ptr() as *const _)
};
if section_var == ptr::null_mut() {
let section_name = b".debug_gdb_scripts\0";
let section_contents = b"\x01gdb_load_rust_pretty_printers.py\0";
unsafe {
let llvm_type = Type::array(&Type::i8(ccx),
section_contents.len() as u64);
let section_var = declare::define_global(ccx, section_var_name,
llvm_type).unwrap_or_else(||{
ccx.sess().bug(&format!("symbol `{}` is already defined", section_var_name))
});
llvm::LLVMSetSection(section_var, section_name.as_ptr() as *const _);
llvm::LLVMSetInitializer(section_var, C_bytes(ccx, section_contents));
llvm::LLVMSetGlobalConstant(section_var, llvm::True);
llvm::LLVMSetUnnamedAddr(section_var, llvm::True);
llvm::SetLinkage(section_var, llvm::Linkage::LinkOnceODRLinkage);
// This should make sure that the whole section is not larger than
// the string it contains. Otherwise we get a warning from GDB.
llvm::LLVMSetAlignment(section_var, 1);
section_var
}
} else {
section_var
}
}
pub fn needs_gdb_debug_scripts_section(ccx: &CrateContext) -> bool {
let omit_gdb_pretty_printer_section =
attr::contains_name(&ccx.tcx()
.map
.krate()
.attrs,
"omit_gdb_pretty_printer_section");
!omit_gdb_pretty_printer_section &&
!ccx.sess().target.target.options.is_like_osx &&
!ccx.sess().target.target.options.is_like_windows &&
ccx.sess().opts.debuginfo != NoDebugInfo
}