[clang] [clang] Implement -fstrict-bool (PR #160790)

[Corentin Jabot via cfe-commits]

=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
=?utf-8?q?Félix?= Cloutier <fcloutier at apple.com>,
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In-Reply-To: <llvm.org/llvm/llvm-project/pull/160790 at github.com>


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@@ -2056,16 +2056,25 @@ llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue,
                           lvalue.getTBAAInfo(), lvalue.isNontemporal());
 }
 
-static bool getRangeForType(CodeGenFunction &CGF, QualType Ty,
-                            llvm::APInt &Min, llvm::APInt &End,
-                            bool StrictEnums, bool IsBool) {
+// This method SHOULD NOT be extended to support additional types, like BitInt
+// types, without an opt-in bool controlled by a CodeGenOptions setting (like
+// -fstrict-bool) and a new UBSan check (like SanitizerKind::Bool) as breaking
+// that assumption would lead to memory corruption. See link for examples of how
+// having a bool that has a value different from 0 or 1 in memory can lead to
+// memory corruption.
+// https://discourse.llvm.org/t/defining-what-happens-when-a-bool-isn-t-0-or-1/86778
+static bool getRangeForType(CodeGenFunction &CGF, QualType Ty, llvm::APInt &Min,
+                            llvm::APInt &End, bool StrictEnums, bool StrictBool,
+                            bool IsBool) {
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cor3ntin wrote:

This will get unwieldy if we get behavior for more types.
Maybe we can have some sort of policy object - maybe not necessary to do that now but it might still be worth it to add a fixme

https://github.com/llvm/llvm-project/pull/160790