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Sema: fix memcpy alias safety incorrect math

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Previously it was not multiplying by the element ABI size. Now, it uses
ptr_add instructions which do math based on the element type.
This commit is contained in:
Andrew Kelley
2023-04-24 21:39:03 -07:00
parent 5378fdffdc
commit 792bbfa301
4 changed files with 58 additions and 27 deletions
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54
src/codegen/llvm.zig
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@@ -7293,39 +7293,53 @@ pub const FuncGen = struct {
fn airPtrAdd(self: *FuncGen, inst: Air.Inst.Index) !?*llvm.Value {
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const bin_op = self.air.extraData(Air.Bin, ty_pl.payload).data;
const base_ptr = try self.resolveInst(bin_op.lhs);
const ptr = try self.resolveInst(bin_op.lhs);
const offset = try self.resolveInst(bin_op.rhs);
const ptr_ty = self.air.typeOf(bin_op.lhs);
const llvm_elem_ty = try self.dg.lowerPtrElemTy(ptr_ty.childType());
if (ptr_ty.ptrSize() == .One) {
// It's a pointer to an array, so according to LLVM we need an extra GEP index.
const indices: [2]*llvm.Value = .{
self.context.intType(32).constNull(), offset,
};
return self.builder.buildInBoundsGEP(llvm_elem_ty, base_ptr, &indices, indices.len, "");
} else {
const indices: [1]*llvm.Value = .{offset};
return self.builder.buildInBoundsGEP(llvm_elem_ty, base_ptr, &indices, indices.len, "");
switch (ptr_ty.ptrSize()) {
.One => {
// It's a pointer to an array, so according to LLVM we need an extra GEP index.
const indices: [2]*llvm.Value = .{ self.context.intType(32).constNull(), offset };
return self.builder.buildInBoundsGEP(llvm_elem_ty, ptr, &indices, indices.len, "");
},
.C, .Many => {
const indices: [1]*llvm.Value = .{offset};
return self.builder.buildInBoundsGEP(llvm_elem_ty, ptr, &indices, indices.len, "");
},
.Slice => {
const base = self.builder.buildExtractValue(ptr, 0, "");
const indices: [1]*llvm.Value = .{offset};
return self.builder.buildInBoundsGEP(llvm_elem_ty, base, &indices, indices.len, "");
},
}
}
fn airPtrSub(self: *FuncGen, inst: Air.Inst.Index) !?*llvm.Value {
const ty_pl = self.air.instructions.items(.data)[inst].ty_pl;
const bin_op = self.air.extraData(Air.Bin, ty_pl.payload).data;
const base_ptr = try self.resolveInst(bin_op.lhs);
const ptr = try self.resolveInst(bin_op.lhs);
const offset = try self.resolveInst(bin_op.rhs);
const negative_offset = self.builder.buildNeg(offset, "");
const ptr_ty = self.air.typeOf(bin_op.lhs);
const llvm_elem_ty = try self.dg.lowerPtrElemTy(ptr_ty.childType());
if (ptr_ty.ptrSize() == .One) {
// It's a pointer to an array, so according to LLVM we need an extra GEP index.
const indices: [2]*llvm.Value = .{
self.context.intType(32).constNull(), negative_offset,
};
return self.builder.buildInBoundsGEP(llvm_elem_ty, base_ptr, &indices, indices.len, "");
} else {
const indices: [1]*llvm.Value = .{negative_offset};
return self.builder.buildInBoundsGEP(llvm_elem_ty, base_ptr, &indices, indices.len, "");
switch (ptr_ty.ptrSize()) {
.One => {
// It's a pointer to an array, so according to LLVM we need an extra GEP index.
const indices: [2]*llvm.Value = .{
self.context.intType(32).constNull(), negative_offset,
};
return self.builder.buildInBoundsGEP(llvm_elem_ty, ptr, &indices, indices.len, "");
},
.C, .Many => {
const indices: [1]*llvm.Value = .{negative_offset};
return self.builder.buildInBoundsGEP(llvm_elem_ty, ptr, &indices, indices.len, "");
},
.Slice => {
const base = self.builder.buildExtractValue(ptr, 0, "");
const indices: [1]*llvm.Value = .{negative_offset};
return self.builder.buildInBoundsGEP(llvm_elem_ty, base, &indices, indices.len, "");
},
}
}