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[IRGen] Prevent overflow in RecordField with large explosions #64828

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Merged
merged 1 commit into from
Apr 7, 2023
Merged

[IRGen] Prevent overflow in RecordField with large explosions #64828

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3 changes: 3 additions & 0 deletions include/swift/AST/DiagnosticsIRGen.def
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Original file line number Diff line number Diff line change
Expand Up @@ -59,5 +59,8 @@ ERROR(temporary_allocation_alignment_not_positive,none,
ERROR(temporary_allocation_alignment_not_power_of_2,none,
"alignment value must be a power of two", ())

ERROR(explosion_size_oveflow,none,
"explosion size too large", ())

#define UNDEFINE_DIAGNOSTIC_MACROS
#include "DefineDiagnosticMacros.h"
13 changes: 10 additions & 3 deletions lib/IRGen/GenRecord.h
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Expand Up @@ -28,7 +28,9 @@
#include "Outlining.h"
#include "TypeInfo.h"
#include "StructLayout.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/TrailingObjects.h"
#include "swift/AST/DiagnosticsIRGen.h"

namespace swift {
namespace irgen {
Expand All @@ -42,8 +44,8 @@ template <class FieldImpl> class RecordField {
template <class, class, class> friend class RecordTypeBuilder;

/// Begin/End - the range of explosion indexes for this element
unsigned Begin : 16;
unsigned End : 16;
unsigned Begin;
unsigned End;

protected:
explicit RecordField(const TypeInfo &elementTI)
Expand Down Expand Up @@ -883,7 +885,12 @@ class RecordTypeBuilder {

auto &fieldInfo = fields.back();
fieldInfo.Begin = explosionSize;
explosionSize += loadableFieldTI->getExplosionSize();
bool overflow = false;
explosionSize = llvm::SaturatingAdd(explosionSize, loadableFieldTI->getExplosionSize(), &overflow);
if (overflow) {
IGM.Context.Diags.diagnose(SourceLoc(), diag::explosion_size_oveflow);
}

fieldInfo.End = explosionSize;
}

Expand Down