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stage1: Fix bitcast of immediate to ptr type (#5131)

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Consider a (legal according to the `@bitCast` rules) conversion from u16
to [2]u8: since the former is a scalar and the latter is a pointer
(arrays are represented at pointers in the codegen phase) we have to
allocate a temporary slot on the stack and then bitcast the resulting
pointer to the desired destination type.

Beware that this means the lifetime of the resulting value is the same
of the function it's contained in and for all intents and purposes
should be regarded as a local (eg. it should not escape).

Closes #4395
Closes #5121
This commit is contained in:
LemonBoy
2020-04-23 18:44:16 +02:00
committed by GitHub
parent 58d5c37409
commit e6428f9401
3 changed files with 24 additions and 5 deletions
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6
src/codegen.cpp
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@@ -3331,12 +3331,16 @@ static LLVMValueRef ir_render_bit_cast(CodeGen *g, IrExecutableGen *executable,
LLVMPointerType(get_llvm_type(g, wanted_type), 0) : get_llvm_type(g, wanted_type);
return LLVMBuildBitCast(g->builder, value, wanted_type_ref, "");
} else if (actual_is_ptr) {
// A scalar is wanted but we got a pointer
LLVMTypeRef wanted_ptr_type_ref = LLVMPointerType(get_llvm_type(g, wanted_type), 0);
LLVMValueRef bitcasted_ptr = LLVMBuildBitCast(g->builder, value, wanted_ptr_type_ref, "");
uint32_t alignment = get_abi_alignment(g, actual_type);
return gen_load_untyped(g, bitcasted_ptr, alignment, false, "");
} else {
zig_unreachable();
// A pointer is wanted but we got a scalar
assert(actual_type->id == ZigTypeIdPointer);
LLVMTypeRef wanted_ptr_type_ref = LLVMPointerType(get_llvm_type(g, wanted_type), 0);
return LLVMBuildBitCast(g->builder, value, wanted_ptr_type_ref, "");
}
}