Impossible address ranges in DWARF debug info

I've been working on a tool that parses DWARF debug info embedded in WebAssembly binaries. The files I'm examining are optimized for size using wasm-opt -Oz -g. I've run into an issue where the address ranges of inlined subroutines will occasionally be impossibly large. Specifically, I'll find a DW_TAG_inlined_subroutine entry with a reasonable DW_AT_low_pc paired with a DW_AT_high_pc with a value of precisely 0x100000000. (Needless to say, the subroutine in question is not actually four gigabytes large.)

I encountered the issue on a bigger codebase, but I've narrowed it down to this simple program that reproduces the issue:

static void increment(int* array, int length) {
    for (int i = 0; i < length; i++) {
        array[i]++;
    }
}

void _start(void) {
    int array[2] = {0, 0};
    increment(array, 2);
}

Compile and optimize like so:

$ clang bug.c -o bug.wasm -Oz -g --target=wasm32 -nostdlib
$ wasm-opt bug.wasm -o bug.wasm -Oz -g

The bug can be confirmed using llvm-dwarfdump:

$ llvm-dwarfdump bug.wasm --name increment
bug.wasm:   file format WASM

0x00000022: DW_TAG_subprogram
              DW_AT_name    ("increment")
              DW_AT_decl_file   ("bug.c")
              DW_AT_decl_line   (1)
              DW_AT_prototyped  (true)
              DW_AT_inline  (DW_INL_inlined)

0x0000007c: DW_TAG_inlined_subroutine
              DW_AT_abstract_origin (0x00000022 "increment")
              DW_AT_low_pc  (0x0000001a)
              DW_AT_high_pc (0x100000000)
              DW_AT_call_file   ("bug.c")
              DW_AT_call_line   (9)
              DW_AT_call_column (0x05)

I don't know the specific cause, but it only happens to code optimized by wasm-opt; clang's output is unaffected. It also only seems to affect DW_TAG_inlined_subroutine DIEs, from what I can tell.

WebAssembly / binaryen

Impossible address ranges in DWARF debug info #6406