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Extract debug_introduce_local_as_var.

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This commit is contained in:
Camille GILLOT 2023-05-07 15:38:14 +00:00
parent 69fef92ab2
commit 1c36f50b3e
1 changed files with 44 additions and 42 deletions
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86
compiler/rustc_codegen_ssa/src/mir/debuginfo.rs
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@ -358,54 +358,56 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let vars = vars.iter().cloned().chain(fallback_var);
for var in vars {
let Some(dbg_var) = var.dbg_var else { continue };
let Some(dbg_loc) = self.dbg_loc(var.source_info) else { continue };
self.debug_introduce_local_as_var(bx, local, base, var);
}
}
let DebugInfoOffset { direct_offset, indirect_offsets, result: _ } =
calculate_debuginfo_offset(bx, local, &var, base.layout);
fn debug_introduce_local_as_var(
&self,
bx: &mut Bx,
local: mir::Local,
base: PlaceRef<'tcx, Bx::Value>,
var: PerLocalVarDebugInfo<'tcx, Bx::DIVariable>,
) {
let Some(dbg_var) = var.dbg_var else { return };
let Some(dbg_loc) = self.dbg_loc(var.source_info) else { return };
// When targeting MSVC, create extra allocas for arguments instead of pointing multiple
// dbg_var_addr() calls into the same alloca with offsets. MSVC uses CodeView records
// not DWARF and LLVM doesn't support translating the resulting
// [DW_OP_deref, DW_OP_plus_uconst, offset, DW_OP_deref] debug info to CodeView.
// Creating extra allocas on the stack makes the resulting debug info simple enough
// that LLVM can generate correct CodeView records and thus the values appear in the
// debugger. (#83709)
let should_create_individual_allocas = bx.cx().sess().target.is_like_msvc
&& self.mir.local_kind(local) == mir::LocalKind::Arg
// LLVM can handle simple things but anything more complex than just a direct
// offset or one indirect offset of 0 is too complex for it to generate CV records
// correctly.
&& (direct_offset != Size::ZERO
|| !matches!(&indirect_offsets[..], [Size::ZERO] | []));
let DebugInfoOffset { direct_offset, indirect_offsets, result: _ } =
calculate_debuginfo_offset(bx, local, &var, base.layout);
if should_create_individual_allocas {
let DebugInfoOffset { direct_offset: _, indirect_offsets: _, result: place } =
calculate_debuginfo_offset(bx, local, &var, base);
// When targeting MSVC, create extra allocas for arguments instead of pointing multiple
// dbg_var_addr() calls into the same alloca with offsets. MSVC uses CodeView records
// not DWARF and LLVM doesn't support translating the resulting
// [DW_OP_deref, DW_OP_plus_uconst, offset, DW_OP_deref] debug info to CodeView.
// Creating extra allocas on the stack makes the resulting debug info simple enough
// that LLVM can generate correct CodeView records and thus the values appear in the
// debugger. (#83709)
let should_create_individual_allocas = bx.cx().sess().target.is_like_msvc
&& self.mir.local_kind(local) == mir::LocalKind::Arg
// LLVM can handle simple things but anything more complex than just a direct
// offset or one indirect offset of 0 is too complex for it to generate CV records
// correctly.
&& (direct_offset != Size::ZERO || !matches!(&indirect_offsets[..], [Size::ZERO] | []));
// Create a variable which will be a pointer to the actual value
let ptr_ty = bx
.tcx()
.mk_ptr(ty::TypeAndMut { mutbl: mir::Mutability::Mut, ty: place.layout.ty });
let ptr_layout = bx.layout_of(ptr_ty);
let alloca = PlaceRef::alloca(bx, ptr_layout);
bx.set_var_name(alloca.llval, &(var.name.to_string() + ".dbg.spill"));
if should_create_individual_allocas {
let DebugInfoOffset { direct_offset: _, indirect_offsets: _, result: place } =
calculate_debuginfo_offset(bx, local, &var, base);
// Write the pointer to the variable
bx.store(place.llval, alloca.llval, alloca.align);
// Create a variable which will be a pointer to the actual value
let ptr_ty = bx
.tcx()
.mk_ptr(ty::TypeAndMut { mutbl: mir::Mutability::Mut, ty: place.layout.ty });
let ptr_layout = bx.layout_of(ptr_ty);
let alloca = PlaceRef::alloca(bx, ptr_layout);
bx.set_var_name(alloca.llval, &(var.name.to_string() + ".dbg.spill"));
// Point the debug info to `*alloca` for the current variable
bx.dbg_var_addr(dbg_var, dbg_loc, alloca.llval, Size::ZERO, &[Size::ZERO], None);
} else {
bx.dbg_var_addr(
dbg_var,
dbg_loc,
base.llval,
direct_offset,
&indirect_offsets,
None,
);
}
// Write the pointer to the variable
bx.store(place.llval, alloca.llval, alloca.align);
// Point the debug info to `*alloca` for the current variable
bx.dbg_var_addr(dbg_var, dbg_loc, alloca.llval, Size::ZERO, &[Size::ZERO], None);
} else {
bx.dbg_var_addr(dbg_var, dbg_loc, base.llval, direct_offset, &indirect_offsets, None);
}
}