Prepare inbounds_gep for opaque pointers

Implement inbounds_gep using LLVMBuildInBoundsGEP2 which takes an
explicit type argument instead of deriving it from a pointer type.

compiler/rustc_codegen_llvm/src/builder.rs

@@ -544,7 +544,11 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
             .val
             .store(&mut body_bx, PlaceRef::new_sized_aligned(current, cg_elem.layout, align));
 
-        let next = body_bx.inbounds_gep(current, &[self.const_usize(1)]);
+        let next = body_bx.inbounds_gep(
+            self.backend_type(cg_elem.layout),
+            current,
+            &[self.const_usize(1)],
+        );
         body_bx.br(header_bx.llbb());
         header_bx.add_incoming_to_phi(current, next, body_bx.llbb());
 
@@ -653,10 +657,16 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         }
     }
 
-    fn inbounds_gep(&mut self, ptr: &'ll Value, indices: &[&'ll Value]) -> &'ll Value {
+    fn inbounds_gep(
+        &mut self,
+        ty: &'ll Type,
+        ptr: &'ll Value,
+        indices: &[&'ll Value],
+    ) -> &'ll Value {
         unsafe {
-            llvm::LLVMBuildInBoundsGEP(
+            llvm::LLVMBuildInBoundsGEP2(
                 self.llbuilder,
+                ty,
                 ptr,
                 indices.as_ptr(),
                 indices.len() as c_uint,

compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs

@@ -15,12 +15,11 @@ use rustc_span::symbol::sym;
 /// .debug_gdb_scripts global is referenced, so it isn't removed by the linker.
 pub fn insert_reference_to_gdb_debug_scripts_section_global(bx: &mut Builder<'_, '_, '_>) {
     if needs_gdb_debug_scripts_section(bx) {
-        let gdb_debug_scripts_section = get_or_insert_gdb_debug_scripts_section_global(bx);
+        let gdb_debug_scripts_section =
+            bx.const_bitcast(get_or_insert_gdb_debug_scripts_section_global(bx), bx.type_i8p());
         // 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 = [bx.const_i32(0), bx.const_i32(0)];
-        let element = bx.inbounds_gep(gdb_debug_scripts_section, &indices);
-        let volative_load_instruction = bx.volatile_load(bx.type_i8(), element);
+        let volative_load_instruction = bx.volatile_load(bx.type_i8(), gdb_debug_scripts_section);
         unsafe {
             llvm::LLVMSetAlignment(volative_load_instruction, 1);
         }

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -686,11 +686,19 @@ fn codegen_emcc_try(
         // create an alloca and pass a pointer to that.
         let ptr_align = bx.tcx().data_layout.pointer_align.abi;
         let i8_align = bx.tcx().data_layout.i8_align.abi;
-        let catch_data =
-            catch.alloca(bx.type_struct(&[bx.type_i8p(), bx.type_bool()], false), ptr_align);
-        let catch_data_0 = catch.inbounds_gep(catch_data, &[bx.const_usize(0), bx.const_usize(0)]);
+        let catch_data_type = bx.type_struct(&[bx.type_i8p(), bx.type_bool()], false);
+        let catch_data = catch.alloca(catch_data_type, ptr_align);
+        let catch_data_0 = catch.inbounds_gep(
+            catch_data_type,
+            catch_data,
+            &[bx.const_usize(0), bx.const_usize(0)],
+        );
         catch.store(ptr, catch_data_0, ptr_align);
-        let catch_data_1 = catch.inbounds_gep(catch_data, &[bx.const_usize(0), bx.const_usize(1)]);
+        let catch_data_1 = catch.inbounds_gep(
+            catch_data_type,
+            catch_data,
+            &[bx.const_usize(0), bx.const_usize(1)],
+        );
         catch.store(is_rust_panic, catch_data_1, i8_align);
         let catch_data = catch.bitcast(catch_data, bx.type_i8p());
 

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -1402,8 +1402,9 @@ extern "C" {
         NumIndices: c_uint,
         Name: *const c_char,
     ) -> &'a Value;
-    pub fn LLVMBuildInBoundsGEP(
+    pub fn LLVMBuildInBoundsGEP2(
         B: &Builder<'a>,
+        Ty: &'a Type,
         Pointer: &'a Value,
         Indices: *const &'a Value,
         NumIndices: c_uint,

compiler/rustc_codegen_llvm/src/va_arg.rs

@@ -50,12 +50,12 @@ fn emit_direct_ptr_va_arg(
 
     let aligned_size = size.align_to(slot_size).bytes() as i32;
     let full_direct_size = bx.cx().const_i32(aligned_size);
-    let next = bx.inbounds_gep(addr, &[full_direct_size]);
+    let next = bx.inbounds_gep(bx.type_i8(), addr, &[full_direct_size]);
     bx.store(next, va_list_addr, bx.tcx().data_layout.pointer_align.abi);
 
     if size.bytes() < slot_size.bytes() && bx.tcx().sess.target.endian == Endian::Big {
         let adjusted_size = bx.cx().const_i32((slot_size.bytes() - size.bytes()) as i32);
-        let adjusted = bx.inbounds_gep(addr, &[adjusted_size]);
+        let adjusted = bx.inbounds_gep(bx.type_i8(), addr, &[adjusted_size]);
         (bx.bitcast(adjusted, bx.cx().type_ptr_to(llty)), addr_align)
     } else {
         (bx.bitcast(addr, bx.cx().type_ptr_to(llty)), addr_align)