From 25354de928f56924b7cbc28a2132e6110262cb57 Mon Sep 17 00:00:00 2001 From: Alex Crichton Date: Tue, 29 Sep 2015 16:26:34 -0700 Subject: [PATCH] trans: Fix __imp_ creation for i686 MSVC Turns out the symbol names are slightly different on 32-bit than on 64, so the prefix needs to be tweaked just a bit! --- src/librustc_trans/trans/base.rs | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/src/librustc_trans/trans/base.rs b/src/librustc_trans/trans/base.rs index 16247b254d9f3..1748a0997c496 100644 --- a/src/librustc_trans/trans/base.rs +++ b/src/librustc_trans/trans/base.rs @@ -2617,6 +2617,15 @@ fn internalize_symbols(cx: &SharedCrateContext, reachable: &HashSet<&str>) { // code references on its own. // See #26591, #27438 fn create_imps(cx: &SharedCrateContext) { + // The x86 ABI seems to require that leading underscores are added to symbol + // names, so we need an extra underscore on 32-bit. There's also a leading + // '\x01' here which disables LLVM's symbol mangling (e.g. no extra + // underscores added in front). + let prefix = if cx.sess().target.target.target_pointer_width == "32" { + "\x01__imp__" + } else { + "\x01__imp_" + }; unsafe { for ccx in cx.iter() { let exported: Vec<_> = iter_globals(ccx.llmod()) @@ -2627,12 +2636,13 @@ fn create_imps(cx: &SharedCrateContext) { let i8p_ty = Type::i8p(&ccx); for val in exported { let name = CStr::from_ptr(llvm::LLVMGetValueName(val)); - let imp_name = String::from("__imp_") + - str::from_utf8(name.to_bytes()).unwrap(); + let mut imp_name = prefix.as_bytes().to_vec(); + imp_name.extend(name.to_bytes()); let imp_name = CString::new(imp_name).unwrap(); let imp = llvm::LLVMAddGlobal(ccx.llmod(), i8p_ty.to_ref(), imp_name.as_ptr() as *const _); - llvm::LLVMSetInitializer(imp, llvm::LLVMConstBitCast(val, i8p_ty.to_ref())); + let init = llvm::LLVMConstBitCast(val, i8p_ty.to_ref()); + llvm::LLVMSetInitializer(imp, init); llvm::SetLinkage(imp, llvm::ExternalLinkage); } }