From 5f18995e23edc944af3a401d9d9d3320a9362652 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Wed, 25 Mar 2020 09:21:05 +0100 Subject: [PATCH] varasm: Fix output_constructor where a RANGE_EXPR index needs to skip some elts [PR94303] The following testcase is miscompiled, because output_constructor doesn't output the initializer correctly. The FE creates {[1...2] = 9} in this case, and we emit .long 9; long 9; .zero 8 instead of the expected .zero 8; .long 9; .long 9. If the CONSTRUCTOR is {[1] = 9, [2] = 9}, output_constructor_regular_field has code to notice that the current location (local->total_bytes) is smaller than the location we want to write to (1*sizeof(elt)) and will call assemble_zeros to skip those. But RANGE_EXPRs are handled by a different function which didn't do this, so for RANGE_EXPRs we emitted them properly only if local->total_bytes was always equal to the location where the RANGE_EXPR needs to start. 2020-03-25 Jakub Jelinek PR middle-end/94303 * varasm.c (output_constructor_array_range): If local->index RANGE_EXPR doesn't start at the current location in the constructor, skip needed number of bytes using assemble_zeros or assert we don't go backwards. PR middle-end/94303 * g++.dg/torture/pr94303.C: New test. --- gcc/ChangeLog | 6 ++++++ gcc/testsuite/ChangeLog | 3 +++ gcc/testsuite/g++.dg/torture/pr94303.C | 17 +++++++++++++++++ gcc/varasm.c | 20 ++++++++++++++++++++ 4 files changed, 46 insertions(+) create mode 100644 gcc/testsuite/g++.dg/torture/pr94303.C diff --git a/gcc/ChangeLog b/gcc/ChangeLog index cde4653c030..3a1bfcef39b 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,11 @@ 2020-03-25 Jakub Jelinek + PR middle-end/94303 + * varasm.c (output_constructor_array_range): If local->index + RANGE_EXPR doesn't start at the current location in the constructor, + skip needed number of bytes using assemble_zeros or assert we don't + go backwards. + PR c++/94223 * langhooks.c (lhd_set_decl_assembler_name): Use a static ulong counter instead of DECL_UID. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 048f830409e..b68779ff339 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,8 @@ 2020-03-25 Jakub Jelinek + PR middle-end/94303 + * g++.dg/torture/pr94303.C: New test. + PR c++/94223 * g++.dg/opt/pr94223.C: New test. diff --git a/gcc/testsuite/g++.dg/torture/pr94303.C b/gcc/testsuite/g++.dg/torture/pr94303.C new file mode 100644 index 00000000000..45b90a2249d --- /dev/null +++ b/gcc/testsuite/g++.dg/torture/pr94303.C @@ -0,0 +1,17 @@ +// PR middle-end/94303 +// { dg-do run } + +struct A { + int d = 9; + A () = default; + A (int x) : d(x) {} + void foo () { if (d < 1) __builtin_abort (); } +}; + +A a[3] = { 1 }; + +int +main () +{ + a[2].foo (); +} diff --git a/gcc/varasm.c b/gcc/varasm.c index dc6da6c0b5b..271a67abf56 100644 --- a/gcc/varasm.c +++ b/gcc/varasm.c @@ -5152,6 +5152,26 @@ struct oc_local_state { static void output_constructor_array_range (oc_local_state *local) { + /* Perform the index calculation in modulo arithmetic but + sign-extend the result because Ada has negative DECL_FIELD_OFFSETs + but we are using an unsigned sizetype. */ + unsigned prec = TYPE_PRECISION (sizetype); + offset_int idx = wi::sext (wi::to_offset (TREE_OPERAND (local->index, 0)) + - wi::to_offset (local->min_index), prec); + tree valtype = TREE_TYPE (local->val); + HOST_WIDE_INT fieldpos + = (idx * wi::to_offset (TYPE_SIZE_UNIT (valtype))).to_short_addr (); + + /* Advance to offset of this element. */ + if (fieldpos > local->total_bytes) + { + assemble_zeros (fieldpos - local->total_bytes); + local->total_bytes = fieldpos; + } + else + /* Must not go backwards. */ + gcc_assert (fieldpos == local->total_bytes); + unsigned HOST_WIDE_INT fieldsize = int_size_in_bytes (TREE_TYPE (local->type)); -- 2.30.2