stage2: add debug info for locals in the LLVM backend

Adds 2 new AIR instructions:
 * dbg_var_ptr
 * dbg_var_val

Sema no longer emits dbg_stmt AIR instructions when strip=true.

LLVM backend: fixed lowerPtrToVoid when calling ptrAlignment on
the element type is problematic.

LLVM backend: fixed alloca instructions improperly getting debug
location annotated, causing chaotic debug info behavior.

zig_llvm.cpp: fixed incorrect bindings for a function that should use
unsigned integers for line and column.

A bunch of C test cases regressed because the new dbg_var AIR
instructions caused their operands to be alive, exposing latent bugs.
Mostly it's just a problem that the C backend lowers mutable
and const slices to the same C type, so we need to represent that in the
C backend instead of printing two duplicate typedefs.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/zig_llvm.cpp b/src/zig_llvm.cpp
index 21e83319d9..528dd2e08a 100644
--- a/src/zig_llvm.cpp
+++ b/src/zig_llvm.cpp
@@ -791,7 +791,9 @@ void ZigLLVMDisposeDIBuilder(ZigLLVMDIBuilder *dbuilder) {
     delete di_builder;
 }
 
-void ZigLLVMSetCurrentDebugLocation(LLVMBuilderRef builder, int line, int column, ZigLLVMDIScope *scope) {
+void ZigLLVMSetCurrentDebugLocation(LLVMBuilderRef builder,
+        unsigned int line, unsigned int column, ZigLLVMDIScope *scope)
+{
     DIScope* di_scope = reinterpret_cast<DIScope*>(scope);
     DebugLoc debug_loc = DILocation::get(di_scope->getContext(), line, column, di_scope, nullptr, false);
     unwrap(builder)->SetCurrentDebugLocation(debug_loc);