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Disable SROA debug info for variables with expressions #61168

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Merged
merged 1 commit into from
Sep 21, 2022
Merged

Disable SROA debug info for variables with expressions #61168

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7 changes: 4 additions & 3 deletions lib/SIL/IR/SILInstructions.cpp
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Expand Up @@ -169,10 +169,11 @@ SILDebugVariable::createFromAllocation(const AllocationInst *AI) {
// TODO: Support AllocBoxInst

if (!VarInfo)
return VarInfo;
return {};

// Copy everything but the DIExpr
VarInfo->DIExpr.clear();
// TODO: Support variables with expressions.
if (VarInfo->DIExpr)
return {};

// Coalesce the debug loc attached on AI into VarInfo
SILType Type = AI->getType();
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5 changes: 2 additions & 3 deletions lib/SILOptimizer/Transforms/SILSROA.cpp
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Expand Up @@ -213,9 +213,8 @@ createAllocas(llvm::SmallVector<AllocStackInst *, 4> &NewAllocations) {
Optional<SILDebugVariable> NewDebugVarInfo =
SILDebugVariable::createFromAllocation(AI);
if (NewDebugVarInfo)
// TODO: Handle DIExpr that is already attached
NewDebugVarInfo->DIExpr = SILDebugInfoExpression::createFragment(VD);

NewDebugVarInfo->DIExpr.append(
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I was thinking: what if we don't clear out DIExpr from the existing VarInfo in SILDebugVariable::createFromAllocation so that this line will append fragment of the inner member. But then I realized we can't have more than one fragment inside a single DIExpression, right? If that's the case, then I do think this is the best solution we have now (until we have the infrastructure to merge two fragments inside a DIExpression)

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You're right — just appending the fragments would be the right thing to do, but it's currently not actually supported. I don't think there's much missing from making this work though.

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Cool! then I think this LGTM.

SILDebugInfoExpression::createFragment(VD));
NewAllocations.push_back(B.createAllocStack(
Loc, Type.getFieldType(VD, M, TypeExpansionContext(B.getFunction())),
NewDebugVarInfo, AI->hasDynamicLifetime(), AI->isLexical()));
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9 changes: 6 additions & 3 deletions test/DebugInfo/sil_based_dbg.swift
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Expand Up @@ -29,10 +29,13 @@ struct TheStruct {
}
// CHECK_DBG_SCOPE-LABEL: sil {{.*}}test_debug_scope
public func test_debug_scope(val : Int) -> Int {
// CHECK_DBG_SCOPE: alloc_stack $Builtin.Int{{[0-9]+}}, var, (name "the_struct",
// CHECK_DBG_SCOPE-SAME: loc
// TODO: Repeated SROA of the same variable is currently disabled.
// CHECK_DBG_SCOPE: alloc_stack $Builtin.Int{{[0-9]+}},
// CHECK_DBG_SCOPE-NOT: var,
// DISABLED_DBG_SCOPE-SAME: var, (name "the_struct",
// DISABLED_DBG_SCOPE-SAME: loc
// The auxiliary debug scope should be removed
// CHECK_DBG_SCOPE-NOT: scope {{[0-9]+}})
// DISABLED_DBG_SCOPE-NOT: scope {{[0-9]+}})
var the_struct = TheStruct(the_member: 0)
the_struct.the_member = val + 13
return the_struct.the_member
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55 changes: 55 additions & 0 deletions test/DebugInfo/srosroa_mem2reg.sil
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@@ -0,0 +1,55 @@
// RUN: %target-sil-opt -enable-sil-verify-all -sil-print-debuginfo -sroa %s | %FileCheck --check-prefix=CHECK-SROA %s
sil_stage canonical

import Builtin
import Swift

struct MyStruct {
@_hasStorage var x: Int64 { get set }
@_hasStorage var y: Int64 { get set }
init(x: Int64, y: Int64)
}

struct MyContainer {
@_hasStorage var z: MyStruct { get set }
}

sil_scope 1 { loc "sroa.swift":2:8 parent @MyStructInit : $@convention(method) (Int64, Int64, @thin MyStruct.Type) -> MyStruct }

// MyStruct.init(x:y:)
sil hidden @MyStructInit : $@convention(method) (Int64, Int64, @thin MyStruct.Type) -> MyStruct {
bb0(%0 : $Int64, %1 : $Int64, %2 : $@thin MyStruct.Type):
%3 = struct $MyStruct (%0 : $Int64, %1 : $Int64), loc "sroa.swift":2:8, scope 1
return %3 : $MyStruct, loc "sroa.swift":2:8, scope 1
} // end sil function 'MyStructInit'

sil_scope 2 { loc "sroa.swift":7:6 parent @foo : $@convention(thin) (Int64, Int64) -> Int64 }

// foo(in_x:in_y:)
sil hidden @foo : $@convention(thin) (Int64, Int64) -> Int64 {
bb0(%0 : $Int64, %1 : $Int64):
debug_value %0 : $Int64, let, name "in_x", argno 1, loc "sroa.swift":7:10, scope 2
debug_value %1 : $Int64, let, name "in_y", argno 2, loc "sroa.swift":7:21, scope 2
%4 = alloc_stack $MyStruct, var, name "my_struct", type $*MyContainer, expr op_fragment:#MyContainer.z, loc "sroa.swift":8:9, scope 2
// Recursive SROA of already SROA-ed aggregates is not yet supported.
// CHECK-SROA: alloc_stack $Int64
// CHECK-SROA-NOT: var,
// CHECK-SROA: alloc_stack $Int64
// CHECK-SROA-NOT: var,
// CHECK-SROA: metatype
%5 = metatype $@thin MyStruct.Type, loc "sroa.swift":8:21, scope 2
%6 = integer_literal $Builtin.Int64, 0, loc "sroa.swift":8:33, scope 2
%7 = struct $Int64 (%6 : $Builtin.Int64), loc "sroa.swift":8:33, scope 2
%8 = integer_literal $Builtin.Int64, 0, loc "sroa.swift":8:39, scope 2
%9 = struct $Int64 (%8 : $Builtin.Int64), loc "sroa.swift":8:39, scope 2
// function_ref MyStruct.init(x:y:)
%10 = function_ref @MyStructInit : $@convention(method) (Int64, Int64, @thin MyStruct.Type) -> MyStruct, loc "sroa.swift":8:21, scope 2
%11 = apply %10(%7, %9, %5) : $@convention(method) (Int64, Int64, @thin MyStruct.Type) -> MyStruct, loc "sroa.swift":8:21, scope 2
store %11 to %4 : $*MyStruct, loc "sroa.swift":8:21, scope 2
%13 = struct_element_addr %4 : $*MyStruct, #MyStruct.x, loc "sroa.swift":9:17, scope 2
store %0 to %13 : $*Int64, loc "sroa.swift":9:17, scope 2
%15 = struct_element_addr %4 : $*MyStruct, #MyStruct.y, loc "sroa.swift":10:17, scope 2
store %1 to %15 : $*Int64, loc "sroa.swift":10:17, scope 2
dealloc_stack %4 : $*MyStruct, loc "sroa.swift":8:9, scope 2
return %0 : $Int64, loc "sroa.swift":11:5, scope 2
} // end sil function 'foo'