From 4e49ba597dc20e0bfd13fc39e0a1c89959576ec5 Mon Sep 17 00:00:00 2001 From: Ayke van Laethem Date: Thu, 31 Oct 2024 10:44:21 +0100 Subject: [PATCH] interrupt: fix bug in interrupt lowering The alignment wasn't set, so defaulted to 4 (for a 32-bit int). LLVM saw this, and therefore assumed that a ptrtoint of the pointer would have had the lowest bits unset. That's an entirely valid optimization, except that we are using these globals for arbitrary values (and aren't actually using these globals). Fixed by setting alignment to 1. It works, though long-term we should maybe find a different solution for this. --- compiler/interrupt.go | 3 +++ 1 file changed, 3 insertions(+) diff --git a/compiler/interrupt.go b/compiler/interrupt.go index 6ba031819..68c8a3605 100644 --- a/compiler/interrupt.go +++ b/compiler/interrupt.go @@ -41,6 +41,8 @@ func (b *builder) createInterruptGlobal(instr *ssa.CallCommon) (llvm.Value, erro // Create a new global of type runtime/interrupt.handle. Globals of this // type are lowered in the interrupt lowering pass. + // It must have an alignment of 1, otherwise LLVM thinks a ptrtoint of the + // global has the lower bits unset. globalType := b.program.ImportedPackage("runtime/interrupt").Type("handle").Type() globalLLVMType := b.getLLVMType(globalType) globalName := b.fn.Package().Pkg.Path() + "$interrupt" + strconv.FormatInt(id.Int64(), 10) @@ -48,6 +50,7 @@ func (b *builder) createInterruptGlobal(instr *ssa.CallCommon) (llvm.Value, erro global.SetVisibility(llvm.HiddenVisibility) global.SetGlobalConstant(true) global.SetUnnamedAddr(true) + global.SetAlignment(1) initializer := llvm.ConstNull(globalLLVMType) initializer = b.CreateInsertValue(initializer, funcContext, 0, "") initializer = b.CreateInsertValue(initializer, funcPtr, 1, "")