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Auto merge of #88629 - wesleywiser:fix_debuginfo_for_scalarpair_params, r=oli-obk
Fix debuginfo for parameters passed via the ScalarPair abi on Windows Mark all of these as locals so the debugger does not try to interpret them as being a pointer to the value. This extends the approach used in #81898. Fixes #88625
2 parents d8d1d10 + a6c642a commit 5fd6f3b

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3 files changed

+112
-15
lines changed

3 files changed

+112
-15
lines changed

‎compiler/rustc_codegen_ssa/src/mir/debuginfo.rs

+10-15
Original file line numberDiff line numberDiff line change
@@ -3,9 +3,11 @@ use rustc_index::vec::IndexVec;
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use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
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use rustc_middle::mir;
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use rustc_middle::ty;
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use rustc_middle::ty::layout::LayoutOf;
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use rustc_session::config::DebugInfo;
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use rustc_span::symbol::{kw, Symbol};
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use rustc_span::{BytePos, Span};
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use rustc_target::abi::Abi;
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use rustc_target::abi::Size;
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use super::operand::{OperandRef, OperandValue};
@@ -368,21 +370,14 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
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{
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let arg_index = place.local.index() - 1;
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if target_is_msvc {
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// Rust compiler decomposes every &str or slice argument into two components:
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// a pointer to the memory address where the data is stored and a usize representing
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// the length of the str (or slice). These components will later be used to reconstruct
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// the original argument inside the body of the function that owns it (see the
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// definition of debug_introduce_local for more details).
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//
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// Since the original argument is declared inside a function rather than being passed
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// in as an argument, it must be marked as a LocalVariable for MSVC debuggers to visualize
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// its data correctly. (See issue #81894 for an in-depth description of the problem).
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match *var_ty.kind() {
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ty::Ref(_, inner_type, _) => match *inner_type.kind() {
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ty::Slice(_) | ty::Str => VariableKind::LocalVariable,
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_ => VariableKind::ArgumentVariable(arg_index + 1),
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},
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_ => VariableKind::ArgumentVariable(arg_index + 1),
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// ScalarPair parameters are spilled to the stack so they need to
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// be marked as a `LocalVariable` for MSVC debuggers to visualize
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// their data correctly. (See #81894 & #88625)
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let var_ty_layout = self.cx.layout_of(var_ty);
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if let Abi::ScalarPair(_, _) = var_ty_layout.abi {
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VariableKind::LocalVariable
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} else {
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VariableKind::ArgumentVariable(arg_index + 1)
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}
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} else {
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// FIXME(eddyb) shouldn't `ArgumentVariable` indices be

‎compiler/rustc_codegen_ssa/src/mir/mod.rs

+1
Original file line numberDiff line numberDiff line change
@@ -129,6 +129,7 @@ impl<'a, 'tcx, V: CodegenObject> LocalRef<'tcx, V> {
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///////////////////////////////////////////////////////////////////////////
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#[instrument(level = "debug", skip(cx))]
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pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
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cx: &'a Bx::CodegenCx,
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instance: Instance<'tcx>,

‎src/test/debuginfo/msvc-scalarpair-params.rs

+101
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,101 @@
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// only-cdb
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// compile-flags: -g
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// cdb-command: g
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// cdb-command: dx r1
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// cdb-check:r1 : (0xa..0xc) [Type: core::ops::range::Range<u32>]
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// cdb-command: dx r2
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// cdb-check:r2 : (0x14..0x1e) [Type: core::ops::range::Range<u64>]
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// cdb-command: g
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// cdb-command: dx r1
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// cdb-check:r1 : (0x9..0x64) [Type: core::ops::range::Range<u32>]
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// cdb-command: dx r2
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// cdb-check:r2 : (0xc..0x5a) [Type: core::ops::range::Range<u64>]
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// cdb-command: g
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// cdb-command: dx o1
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// cdb-check:o1 : Some [Type: enum$<core::option::Option<u32> >]
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// cdb-check: [variant] : Some
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// cdb-check: [+0x004] __0 : 0x4d2 [Type: [...]]
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// cdb-command: dx o2
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// cdb-check:o2 : Some [Type: enum$<core::option::Option<u64> >]
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// cdb-check: [variant] : Some
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// cdb-check: [+0x008] __0 : 0x162e [Type: unsigned __int64]
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// cdb-command: g
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// cdb-command: dx t1
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// cdb-check:t1 : (0xa, 0x14) [Type: tuple$<u32,u32>]
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// cdb-check: [0] : 0xa [Type: unsigned int]
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// cdb-check: [1] : 0x14 [Type: unsigned int]
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// cdb-command: dx t2
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// cdb-check:t2 : (0x1e, 0x28) [Type: tuple$<u64,u64>]
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// cdb-check: [0] : 0x1e [Type: unsigned __int64]
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// cdb-check: [1] : 0x28 [Type: unsigned __int64]
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// cdb-command: g
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// cdb-command: dx s
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// cdb-check:s : "this is a static str" [Type: str]
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// cdb-check: [len] : 0x14 [Type: unsigned [...]]
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// cdb-check: [chars]
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// cdb-command: g
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// cdb-command: dx s
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// cdb-check:s : { len=0x5 } [Type: slice$<u8>]
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// cdb-check: [len] : 0x5 [Type: unsigned [...]]
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// cdb-check: [0] : 0x1 [Type: unsigned char]
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// cdb-check: [1] : 0x2 [Type: unsigned char]
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// cdb-check: [2] : 0x3 [Type: unsigned char]
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// cdb-check: [3] : 0x4 [Type: unsigned char]
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// cdb-check: [4] : 0x5 [Type: unsigned char]
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58+
use std::ops::Range;
59+
60+
fn range(r1: Range<u32>, r2: Range<u64>) {
61+
zzz(); // #break
62+
}
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64+
fn range_mut(mut r1: Range<u32>, mut r2: Range<u64>) {
65+
if r1.start == 9 {
66+
r1.end = 100;
67+
}
68+
69+
if r2.start == 12 {
70+
r2.end = 90;
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}
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zzz(); // #break
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}
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fn option(o1: Option<u32>, o2: Option<u64>) {
77+
zzz(); // #break
78+
}
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80+
fn tuple(t1: (u32, u32), t2: (u64, u64)) {
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zzz(); // #break
82+
}
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fn str(s: &str) {
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zzz(); // #break
86+
}
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fn slice(s: &[u8]) {
89+
zzz(); // #break
90+
}
91+
92+
fn zzz() { }
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fn main() {
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range(10..12, 20..30);
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range_mut(9..20, 12..80);
97+
option(Some(1234), Some(5678));
98+
tuple((10, 20), (30, 40));
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str("this is a static str");
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slice(&[1, 2, 3, 4, 5]);
101+
}

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