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Auto merge of #28427 - DiamondLovesYou:gdb-debug-script-load, r=alexcrichton

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This is so LLVM isn't forced to load every byte of it. Also sets the alignment of
the load. Adds a test for the debug script section.

r? @alexcrichton
This commit is contained in:
bors 2015-09-22 03:35:55 +00:00
commit f07f4ef743
10 changed files with 50 additions and 4 deletions
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14
src/librustc_trans/trans/debuginfo/gdb.rs
View file

@ -13,7 +13,7 @@
use llvm;
use llvm::ValueRef;
use trans::common::{C_bytes, CrateContext};
use trans::common::{C_bytes, CrateContext, C_i32};
use trans::declare;
use trans::type_::Type;
use session::config::NoDebugInfo;
@ -31,11 +31,21 @@ pub fn insert_reference_to_gdb_debug_scripts_section_global(ccx: &CrateContext)
let gdb_debug_scripts_section_global =
get_or_insert_gdb_debug_scripts_section_global(ccx);
unsafe {
// Load just the first byte as that's all that's necessary to force
// LLVM to keep around the reference to the global.
let indices = [C_i32(ccx, 0), C_i32(ccx, 0)];
let element =
llvm::LLVMBuildInBoundsGEP(ccx.raw_builder(),
gdb_debug_scripts_section_global,
indices.as_ptr(),
indices.len() as ::libc::c_uint,
empty.as_ptr());
let volative_load_instruction =
llvm::LLVMBuildLoad(ccx.raw_builder(),
gdb_debug_scripts_section_global,
element,
empty.as_ptr());
llvm::LLVMSetVolatile(volative_load_instruction, llvm::True);
llvm::LLVMSetAlignment(volative_load_instruction, 1);
}
}
}