From 5ec9f8cff333bbe9ef6b3767bfcc334961927a03 Mon Sep 17 00:00:00 2001 From: Bernd Edlinger Date: Thu, 13 Sep 2018 21:43:16 +0000 Subject: [PATCH] varasm.c (compare_constant): Compare type size of STRING_CSTs. * varasm.c (compare_constant): Compare type size of STRING_CSTs. (get_constant_size): Don't make STRING_CSTs larger than they are. (check_string_literal): New check function for STRING_CSTs. (output_constant): Use it. From-SVN: r264292 --- gcc/ChangeLog | 7 +++++++ gcc/varasm.c | 34 +++++++++++++++++++++++++++++++--- 2 files changed, 38 insertions(+), 3 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index a7585bbe53d..7dfcd97f901 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2018-09-13 Bernd Edlinger + + * varasm.c (compare_constant): Compare type size of STRING_CSTs. + (get_constant_size): Don't make STRING_CSTs larger than they are. + (check_string_literal): New check function for STRING_CSTs. + (output_constant): Use it. + 2018-09-13 Eric Botcazou PR target/86812 diff --git a/gcc/varasm.c b/gcc/varasm.c index 27d878f218a..e46bc5930fc 100644 --- a/gcc/varasm.c +++ b/gcc/varasm.c @@ -3146,7 +3146,9 @@ compare_constant (const tree t1, const tree t2) return FIXED_VALUES_IDENTICAL (TREE_FIXED_CST (t1), TREE_FIXED_CST (t2)); case STRING_CST: - if (TYPE_MODE (TREE_TYPE (t1)) != TYPE_MODE (TREE_TYPE (t2))) + if (TYPE_MODE (TREE_TYPE (t1)) != TYPE_MODE (TREE_TYPE (t2)) + || int_size_in_bytes (TREE_TYPE (t1)) + != int_size_in_bytes (TREE_TYPE (t2))) return 0; return (TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2) @@ -3303,8 +3305,9 @@ get_constant_size (tree exp) HOST_WIDE_INT size; size = int_size_in_bytes (TREE_TYPE (exp)); - if (TREE_CODE (exp) == STRING_CST) - size = MAX (TREE_STRING_LENGTH (exp), size); + gcc_checking_assert (size >= 0); + gcc_checking_assert (TREE_CODE (exp) != STRING_CST + || size >= TREE_STRING_LENGTH (exp)); return size; } @@ -4773,6 +4776,30 @@ initializer_constant_valid_for_bitfield_p (tree value) return false; } +/* Check if a STRING_CST fits into the field. + Tolerate only the case when the NUL termination + does not fit into the field. */ + +static bool +check_string_literal (tree string, unsigned HOST_WIDE_INT size) +{ + tree type = TREE_TYPE (string); + tree eltype = TREE_TYPE (type); + unsigned HOST_WIDE_INT elts = tree_to_uhwi (TYPE_SIZE_UNIT (eltype)); + unsigned HOST_WIDE_INT mem_size = tree_to_uhwi (TYPE_SIZE_UNIT (type)); + int len = TREE_STRING_LENGTH (string); + + if (elts != 1 && elts != 2 && elts != 4) + return false; + if (len < 0 || len % elts != 0) + return false; + if (size < (unsigned)len) + return false; + if (mem_size != size) + return false; + return true; +} + /* output_constructor outer state of relevance in recursive calls, typically for nested aggregate bitfields. */ @@ -4941,6 +4968,7 @@ output_constant (tree exp, unsigned HOST_WIDE_INT size, unsigned int align, case STRING_CST: thissize = MIN ((unsigned HOST_WIDE_INT)TREE_STRING_LENGTH (exp), size); + gcc_checking_assert (check_string_literal (exp, size)); assemble_string (TREE_STRING_POINTER (exp), thissize); break; case VECTOR_CST: -- 2.30.2