$ xref diff-c

Normalized cross-build pseudo-C diff between counterpart functions in two binaries.

Matches stripped functions between two builds (68aa57b vs v0.0.2 / e6037d0) by structural invariants and diffs normalized pseudo-C without address noise.

Usage

xref diff-c [OPTIONS] --other <OTHER> <ADDRS>...

Arguments and options

Arguments

Options

Examples

All examples were recorded on public binaries; see Provenance.

Diff-c ... 0xc7d60 (identical)

Confirms zero logic change in 0xc7d60 vs 0xcf8d0 across builds (116 normalized lines identical).

$ xref -b xref.stripped diff-c --other xref-v0.0.2.stripped 0xc7d60

  warning: scores, ratios and pseudo-C similarities are heuristics, not calibrated probabilities or semantic equivalence proof
  warning: candidate list capped at 128 of 292; omitted plausible candidates keep ambiguity
  warning: pseudo-C ordering is heuristic inference; structural scores remain explicit
=== diff 0xc7d60..0xc7fbf (current) vs 0xcf8d0..0xcfb2f (other, score 261: locs:80 strs:0 imms:11 disps:0 nbrs:145 size:0x25f callees:4; pseudo-C similarity 1.000 (heuristic)) ===
  identical normalized pseudo-C (116 lines)

xref: load 518.7µs, total 18.6ms

Diff-c ... 0xd57c0 (changed)

Compact cross-build diff between 0xd57c0 (68aa57b) and 0xd5530 (v0.0.2).

$ xref -b xref.stripped diff-c --other xref-v0.0.2.stripped 0xd57c0

  warning: scores, ratios and pseudo-C similarities are heuristics, not calibrated probabilities or semantic equivalence proof
  warning: candidate list capped at 128 of 396; omitted plausible candidates keep ambiguity
  warning: pseudo-C ordering is heuristic inference; structural scores remain explicit
=== diff 0xd57c0..0xd6301 (current) vs 0xd5530..0xd6071 (other, score 384: locs:240 strs:0 imms:4 disps:10 nbrs:105 size:0xb41 callees:8) ===
  ...
      }
      @var_11 = (@slot_10 + @var_8);
-     @var_1 = 0xc2bc;
+     @var_1 = 0xc518;
      @var_32 = @slot_9;
      switch (*(u64 *)(@var_11)) {
  ...

xref: load 553.1µs, total 44.9ms

Reading the output

• The warning: lines state that scores and similarities are heuristics.
• The === diff header names both functions, the structural score from match and the pseudo-C similarity.
• Then either identical normalized pseudo-C (N lines) or a line diff: - lines only in the current build, + lines only in the other, ... marks unchanged lines left out. Addresses, labels and skip flags are normalized away before comparing.

Limits

• Equal normalized pseudo-C is strong evidence of unchanged logic, not a proof; constants folded differently by the compiler show up as differences.
• The counterpart is chosen by match; check its score margin when several candidates are close.

Provenance

Recorded with a development build of xref after 0.4.0 on Linux x86-64, on xref.stripped = a stripped xref build (the binary of the home-page examples); xref-v0.0.2.stripped = stripped xref 0.0.2. Output is unchanged except that whitespace at the end of each line and empty lines at the end of the output are removed; long outputs are cut where marked.

Source: docs/cli/diff-c.md · generated for the site; edit the Markdown, not this page.