diff options
Diffstat (limited to 'gcc/tree-ssa-operands.c')
| -rw-r--r-- | gcc/tree-ssa-operands.c | 52 |
1 files changed, 43 insertions, 9 deletions
diff --git a/gcc/tree-ssa-operands.c b/gcc/tree-ssa-operands.c index 87eec74..cd8ade6 100644 --- a/gcc/tree-ssa-operands.c +++ b/gcc/tree-ssa-operands.c @@ -1367,8 +1367,33 @@ access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset, return true; } + +/* Given an aggregate expression FULL_REF, return the number of + aggregates that are containing FULL_REF. So, given a structure + reference a.b.c.d, the nesting level for this expression is 2 (the + number of '.' in the expression minus 1). */ + +static unsigned +ref_nesting_level (tree full_ref) +{ + unsigned nesting_level = 0; + + if (!handled_component_p (full_ref)) + return 0; + + full_ref = TREE_OPERAND (full_ref, 0); + while (handled_component_p (full_ref)) + { + nesting_level++; + full_ref = TREE_OPERAND (full_ref, 0); + } + + return nesting_level; +} + + /* Add the actual variables FULL_REF can access, given a member of - full_ref's points-to set VAR, where FULL_REF is an access of SIZE at + FULL_REF's points-to set VAR, where FULL_REF is an access of SIZE at OFFSET from var. IS_CALL_SITE is true if this is a call, and IS_DEF is true if this is supposed to be a vdef, and false if this should be a VUSE. @@ -1386,10 +1411,12 @@ access_can_touch_variable (tree ref, tree alias, HOST_WIDE_INT offset, This is necessary because foop only actually points to foo's first member, so that is all the points-to set contains. However, an access to foop->a may be touching some single SFT if we have created some - SFT's for a structure. */ + SFT's for a structure. + + FULL_REF is the original memory expression being analyzed. */ static bool -add_vars_for_offset (tree var, unsigned HOST_WIDE_INT offset, +add_vars_for_offset (tree full_ref, tree var, unsigned HOST_WIDE_INT offset, unsigned HOST_WIDE_INT size, bool is_def) { bool added = false; @@ -1397,14 +1424,21 @@ add_vars_for_offset (tree var, unsigned HOST_WIDE_INT offset, subvar_t sv; unsigned int i; - if (SFT_IN_NESTED_STRUCT (var)) + if (full_ref + && SFT_NESTING_LEVEL (var) > 0 + && ref_nesting_level (full_ref) < SFT_NESTING_LEVEL (var)) { /* Since VAR is an SFT inside a nested structure, the OFFSET computed by get_ref_base_and_extent is the offset from the - start of the immediately containing structure. However, to - find out what other SFTs are affected by this reference, we - need to know the offsets starting at the root structure in - the nesting hierarchy. + start of the immediately containing structure. If VAR is an + SFT inside a nested structure, then FULL_REF may be a + reference to the structure immediately enclosing SFT, and so + OFFSET will be the offset from the start of the immediately + enclosing structure. + + However, to find out what other SFTs are affected by this + reference, we need to know the offsets starting at the root + structure in the nesting hierarchy. For instance, given the following structure: @@ -1541,7 +1575,7 @@ add_virtual_operand (tree var, stmt_ann_t s_ann, int flags, if it is a potential points-to location. */ if (TREE_CODE (al) == STRUCT_FIELD_TAG && TREE_CODE (var) == NAME_MEMORY_TAG) - none_added &= !add_vars_for_offset (al, offset, size, + none_added &= !add_vars_for_offset (full_ref, al, offset, size, flags & opf_def); else { |