From 2a50b401465f74d7f3ee1654915b9070b4dc0fee Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Fri, 15 May 2020 18:06:05 +0930 Subject: [PATCH] Fix tight loop on recursively-defined symbols This patch fixes a bug in GAS where the assembler enters a tight loop when attempting to resolve recursively-defined symbols, e.g. when trying to assemble "a=a". This is a regression introduced between binutils 2.32 and 2.33, by commit 1903f1385bff9 * symbols.c (struct local_symbol): Update comment. (resolve_symbol_value): For resolved symbols equated to other symbols, verify that the referenced symbol is not a local_symbol before accessing sy_value. Don't leave symbol loops during finalize_syms resolution. * testsuite/gas/all/assign-bad-recursive.d: New test. * testsuite/gas/all/assign-bad-recursive.l: Error output for test. * testsuite/gas/all/assign-bad-recursive.s: Assembly for test. * testsuite/gas/all/gas.exp: Run it. --- gas/ChangeLog | 13 +++++++++++++ gas/symbols.c | 18 +++++++++++++++--- gas/testsuite/gas/all/assign-bad-recursive.d | 4 ++++ gas/testsuite/gas/all/assign-bad-recursive.l | 7 +++++++ gas/testsuite/gas/all/assign-bad-recursive.s | 8 ++++++++ gas/testsuite/gas/all/gas.exp | 1 + 6 files changed, 48 insertions(+), 3 deletions(-) create mode 100644 gas/testsuite/gas/all/assign-bad-recursive.d create mode 100644 gas/testsuite/gas/all/assign-bad-recursive.l create mode 100644 gas/testsuite/gas/all/assign-bad-recursive.s diff --git a/gas/ChangeLog b/gas/ChangeLog index 3a1f406fd82..2a987616ece 100644 --- a/gas/ChangeLog +++ b/gas/ChangeLog @@ -1,3 +1,16 @@ +2020-05-15 Alan Modra + Alex Coplan + + * symbols.c (struct local_symbol): Update comment. + (resolve_symbol_value): For resolved symbols equated to other + symbols, verify that the referenced symbol is not a local_symbol + before accessing sy_value. Don't leave symbol loops during + finalize_syms resolution. + * testsuite/gas/all/assign-bad-recursive.d: New test. + * testsuite/gas/all/assign-bad-recursive.l: Error output for test. + * testsuite/gas/all/assign-bad-recursive.s: Assembly for test. + * testsuite/gas/all/gas.exp: Run it. + 2020-05-14 Nick Clifton * po/sv.po: Updated Swedish translation. diff --git a/gas/symbols.c b/gas/symbols.c index 160b0f74021..711730daf1c 100644 --- a/gas/symbols.c +++ b/gas/symbols.c @@ -114,7 +114,7 @@ struct symbol /* A pointer in the symbol may point to either a complete symbol (struct symbol above) or to a local symbol (struct local_symbol defined here). The symbol code can detect the case by examining - the first field. It is always NULL for a local symbol. + the first field which is present in both structs. We do this because we ordinarily only need a small amount of information for a local symbol. The symbol table takes up a lot of @@ -1237,11 +1237,18 @@ resolve_symbol_value (symbolS *symp) if (symp->sy_flags.sy_resolved) { final_val = 0; - while (symp->sy_value.X_op == O_symbol - && symp->sy_value.X_add_symbol->sy_flags.sy_resolved) + while (symp->sy_value.X_op == O_symbol) { final_val += symp->sy_value.X_add_number; symp = symp->sy_value.X_add_symbol; + if (LOCAL_SYMBOL_CHECK (symp)) + { + struct local_symbol *locsym = (struct local_symbol *) symp; + final_val += locsym->lsy_value; + return final_val; + } + if (!symp->sy_flags.sy_resolved) + return 0; } if (symp->sy_value.X_op == O_constant) final_val += symp->sy_value.X_add_number; @@ -1380,6 +1387,11 @@ resolve_symbol_value (symbolS *symp) break; } + /* Don't leave symbol loops. */ + if (finalize_syms + && add_symbol->sy_flags.sy_resolving) + break; + if (finalize_syms && final_val == 0) { if (LOCAL_SYMBOL_CHECK (add_symbol)) diff --git a/gas/testsuite/gas/all/assign-bad-recursive.d b/gas/testsuite/gas/all/assign-bad-recursive.d new file mode 100644 index 00000000000..aeec5d55f8a --- /dev/null +++ b/gas/testsuite/gas/all/assign-bad-recursive.d @@ -0,0 +1,4 @@ +#name: bad recursive assignments +#source: assign-bad-recursive.s +#xfail: bfin-*-* +#error_output: assign-bad-recursive.l diff --git a/gas/testsuite/gas/all/assign-bad-recursive.l b/gas/testsuite/gas/all/assign-bad-recursive.l new file mode 100644 index 00000000000..70eaf0fe2e3 --- /dev/null +++ b/gas/testsuite/gas/all/assign-bad-recursive.l @@ -0,0 +1,7 @@ +[^:]*: Assembler messages: +.*: Error: symbol definition loop encountered at `aaa' +#... +.*: Error: symbol definition loop encountered at `iii' +#... +.*: Error: symbol definition loop encountered at `xxx' +#pass diff --git a/gas/testsuite/gas/all/assign-bad-recursive.s b/gas/testsuite/gas/all/assign-bad-recursive.s new file mode 100644 index 00000000000..21917d91ff6 --- /dev/null +++ b/gas/testsuite/gas/all/assign-bad-recursive.s @@ -0,0 +1,8 @@ + aaa = aaa + + iii = jjj + jjj = iii + + xxx = yyy + yyy = zzz + zzz = xxx diff --git a/gas/testsuite/gas/all/gas.exp b/gas/testsuite/gas/all/gas.exp index d4140537827..1664018c0f9 100644 --- a/gas/testsuite/gas/all/gas.exp +++ b/gas/testsuite/gas/all/gas.exp @@ -97,6 +97,7 @@ if { ![istarget "bfin-*-*"] } then { gas_test "assign-ok.s" "" "" "== assignment support" } gas_test_error "assign-bad.s" "" "== assignment for symbol already set" +run_dump_test assign-bad-recursive run_dump_test simple-forward run_dump_test forward -- 2.30.2