1#!/bin/bash 2# SPDX-License-Identifier: GPL-2.0 3# 4# Two ThinLTO-promoted symbols sharing a demangled name must be paired up 5# correctly. 6# 7# A file-local symbol which ThinLTO has to make visible is renamed 8# helper.llvm.<hash>. With two such helpers in one link the original and the 9# patched object hold two each, all four spelled differently, and demangling 10# gives "helper" for all of them -- so the name is not enough to say which 11# corresponds to which. 12# 13# Getting it wrong is silent and specific: the patch is built against the wrong 14# body, so one call site gets the other helper's arithmetic. Nothing fails to 15# build and nothing fails to load. 16# 17# test-thinlto-local covers the unambiguous case, one promoted symbol whose 18# hash moved. This is the case where demangling alone is not an answer. 19# 20# The outcome is asserted, not the machinery: with the clang tested here the 21# pairing succeeds even with the .llvm.<hash> suffix map disabled and with 22# llvm_suffix() stubbed out, so no single-line sabotage distinguishes it. The 23# tiered matcher this case was written for is not needed for this shape. 24# 25# Covers the same ground as corpus/x86_64-llvm-thinlto/ 26# thin-lto-demangled-ambiguity and thin-lto-demangled-global-match in Joe 27# Lawrence's klp-build unit test corpus. 28 29. "$(dirname "$0")/../lib.sh" 30 31setup 32clang_only "ThinLTO requires clang" 33 34find_thinlto_toolchain || 35 probe_skip "no matching clang/lld pair for a ThinLTO link; set THIN_LD to one" 36 37build_thinlto() # $1 output object, $2 extra flags 38{ 39 local t 40 for t in "" -DTU_B -DTU_C; do 41 $THIN_CC -flto=thin -O2 -ffunction-sections -fdata-sections \ 42 $2 $t -c "$FIXTURES_DIR/thinlto_ambiguity.c" \ 43 -o "$workdir/tu$t.o" 2>/dev/null || return 1 44 done 45 "$THIN_LD" -r "$workdir/tu.o" "$workdir/tu-DTU_B.o" "$workdir/tu-DTU_C.o" \ 46 -o "$1" 2>/dev/null || return 1 47} 48 49build_thinlto "$workdir/orig.o" "" || 50 probe_skip "ThinLTO build failed ($THIN_CC, $THIN_LD)" 51build_thinlto "$workdir/patched.o" -DPATCHED || 52 probe_skip "ThinLTO build failed ($THIN_CC, $THIN_LD)" 53 54# The premise: two promoted helpers per object, and exactly one of them kept 55# its hash -- the one the patch did not touch. Without that there is nothing 56# to disambiguate. 57orig_syms="$(in_symbols orig.o | grep -oE 'helper\.llvm\.[0-9]+' | sort -u)" 58new_syms="$( in_symbols patched.o | grep -oE 'helper\.llvm\.[0-9]+' | sort -u)" 59[ "$(echo "$orig_syms" | wc -l)" = 2 ] && [ "$(echo "$new_syms" | wc -l)" = 2 ] || 60 probe_skip "ThinLTO did not promote two distinct helpers here" 61 62kept="$(comm -12 <(echo "$orig_syms") <(echo "$new_syms"))" 63moved="$(comm -13 <(echo "$orig_syms") <(echo "$new_syms"))" 64[ "$(echo "$kept" | wc -w)" = 1 ] && [ "$(echo "$moved" | wc -w)" = 1 ] || 65 probe_skip "expected one helper to keep its hash and one to move" 66 67run_diff 68 69# Exactly one helper is cloned, and it is the one whose body changed. Cloning 70# the other, or both, is what a wrong pairing looks like. 71assert_not_patched "$kept" 72 73n="$(out_sections | grep -cE '[[:space:]]\.text\.helper\.llvm\.[0-9]+[[:space:]]')" 74[ "$n" = 1 ] || 75 fail "expected 1 cloned helper, found $n" 76 77pass "ThinLTO helpers sharing a demangled name paired up correctly" 78