Hi,
this is the revised version of my patch. I had trouble to get your
point regarding the float_visitor:
> If the constant is seen first, then the non-constant won't be favored
> (though perhaps binary ops get canonicalized so that constants are on
> the RHS?).
Only the assignment of m_result in visit_constant_svalue is guarded by
!m_result, while the other two are not. So, there are two possibilities:
1. A constant is seen first and then assigned to m_result.
1.1. A non-constant float operand is seen later and
overwrites m_result.
1.2. There's no non-constant float operand, thus the
constant is the actual floating-point operand and
is kept inside m_result.
2. A non-constant is seen first, then m_result might be
overwritten with another non-constant later but never
with a constant.
Do I have a flaw in my thinking? (But they do seem to get canonicalized,
so that shouldn't matter)
> How about:
> -Wanalyzer-imprecise-float-arithmetic
> -Wanalyzer-imprecise-fp-arithmetic
> instead? (ideas welcome)
I've chosen the second. I mostly tried to avoid float because it is also
a reserved keyword in many languages and I wanted to avoid confusion
(might be overthinking that).
- Tim
This patch fixes the ICE reported in PR106181 and adds a new warning to
the analyzer complaining about the use of floating-point operands.
Regrtested on Linux x86_64.
2022-08-17 Tim Lange
gcc/analyzer/ChangeLog:
PR analyzer/106181
* analyzer.opt: Add Wanalyzer-imprecise-floating-point-arithmetic.
* region-model.cc (is_any_cast_p): Formatting.
(region_model::check_region_size): Ensure precondition.
(class imprecise_floating_point_arithmetic): New abstract
diagnostic class for all floating-point related warnings.
(class float_as_size_arg): Concrete diagnostic class to complain
about floating-point operands inside the size argument.
(class contains_floating_point_visitor):
New visitor to find floating-point operands inside svalues.
(region_model::check_dynamic_size_for_floats): New function.
(region_model::set_dynamic_extents):
Call to check_dynamic_size_for_floats.
* region-model.h (class region_model):
Add region_model::check_dynamic_size_for_floats.
gcc/ChangeLog:
PR analyzer/106181
* doc/invoke.texi: Add Wanalyzer-imprecise-fp-arithmetic.
gcc/testsuite/ChangeLog:
PR analyzer/106181
* gcc.dg/analyzer/allocation-size-1.c: New test.
* gcc.dg/analyzer/imprecise-floating-point-1.c: New test.
* gcc.dg/analyzer/pr106181.c: New test.
---
gcc/analyzer/analyzer.opt | 4 +
gcc/analyzer/region-model.cc | 179 +++---
gcc/analyzer/region-model.h | 2 +
gcc/doc/invoke.texi | 14 ++
.../gcc.dg/analyzer/allocation-size-1.c | 10 +
.../analyzer/imprecise-floating-point-1.c | 74
gcc/testsuite/gcc.dg/analyzer/pr106181.c | 11 ++
7 files changed, 271 insertions(+), 23 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/analyzer/imprecise-floating-point-1.c
create mode 100644 gcc/testsuite/gcc.dg/analyzer/pr106181.c
diff --git a/gcc/analyzer/analyzer.opt b/gcc/analyzer/analyzer.opt
index 61b58c575ff..437ea92e130 100644
--- a/gcc/analyzer/analyzer.opt
+++ b/gcc/analyzer/analyzer.opt
@@ -98,6 +98,10 @@ Wanalyzer-free-of-non-heap
Common Var(warn_analyzer_free_of_non_heap) Init(1) Warning
Warn about code paths in which a non-heap pointer is freed.
+Wanalyzer-imprecise-fp-arithmetic
+Common Var(warn_analyzer_imprecise_fp_arithmetic) Init(1) Warning
+Warn about code paths in which floating-point arithmetic is used in locations
where precise computation is needed.
+
Wanalyzer-jump-through-null
Common Var(warn_analyzer_jump_through_null) Init(1) Warning
Warn about code paths in which a NULL function pointer is called.
diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc
index b5bc3efda32..ec29be259b5 100644
--- a/gcc/analyzer/region-model.cc
+++ b/gcc/analyzer/region-model.cc
@@ -3301,7 +3301,8 @@ public:
m.add_cwe (131);
return warning_meta (rich_loc, m, get_controlling_option (),
- "allocated buffer size is not a multiple of the pointee's size");
+"allocated buffer size is not a multiple"
+" of the pointee's size");
}
label_text
@@ -3396,21 +3397,20 @@ capacity_compatible_with_type (tree cst, tree
pointee_size_tree)
class size_visitor : public visitor
{
public:
- size_visitor (tree size_cst, const svalue *sval, constraint_manager *cm)
- : m_size_cst (size_cst), m_sval (sval), m_cm (cm)
+ size_visitor (tree size_cst, const svalue *root_sval, constraint_manager *cm)
+ : m_size_cst (size_cst), m_root_sval (roo
