It seems the two failing tests can be simply fixed after r348037
Fix 3 cases in Analysis/builtin-functions.cpp
Delete the bad CodeGen/builtin-constant-p.c for now
llvm-svn: 348053
Kept the "indirect_builtin_constant_p" test case in test/SemaCXX/constant-expression-cxx1y.cpp
while we are investigating why the following snippet fails:
extern char extern_var;
struct { int a; } a = {__builtin_constant_p(extern_var)};
llvm-svn: 348039
This was reverted in r347656 due to me thinking it caused a miscompile of
Chromium. Turns out it was the Chromium code that was broken.
llvm-svn: 347756
This caused a miscompile in Chrome (see crbug.com/908372) that's
illustrated by this small reduction:
static bool f(int *a, int *b) {
return !__builtin_constant_p(b - a) || (!(b - a));
}
int arr[] = {1,2,3};
bool g() {
return f(arr, arr + 3);
}
$ clang -O2 -S -emit-llvm a.cc -o -
g() should return true, but after r347417 it became false for some reason.
This also reverts the follow-up commits.
r347417:
> Re-Reinstate 347294 with a fix for the failures.
>
> Don't try to emit a scalar expression for a non-scalar argument to
> __builtin_constant_p().
>
> Third time's a charm!
r347446:
> The result of is.constant() is unsigned.
r347480:
> A __builtin_constant_p() returns 0 with a function type.
r347512:
> isEvaluatable() implies a constant context.
>
> Assume that we're in a constant context if we're asking if the expression can
> be compiled into a constant initializer. This fixes the issue where a
> __builtin_constant_p() in a compound literal was diagnosed as not being
> constant, even though it's always possible to convert the builtin into a
> constant.
r347531:
> A "constexpr" is evaluated in a constant context. Make sure this is reflected
> if a __builtin_constant_p() is a part of a constexpr.
llvm-svn: 347656
Assume that we're in a constant context if we're asking if the expression can
be compiled into a constant initializer. This fixes the issue where a
__builtin_constant_p() in a compound literal was diagnosed as not being
constant, even though it's always possible to convert the builtin into a
constant.
llvm-svn: 347512
Summary:
A __builtin_constant_p may end up with a constant after inlining. Use
the is.constant intrinsic if it's a variable that's in a context where
it may resolve to a constant, e.g., an argument to a function after
inlining.
Reviewers: rsmith, shafik
Subscribers: jfb, kristina, cfe-commits, nickdesaulniers, jyknight
Differential Revision: https://reviews.llvm.org/D54355
llvm-svn: 347294
Summary:
Compound literals, enums, file-scoped arrays, etc. require their
initializers and size specifiers to be constant. Wrap the initializer
expressions in a ConstantExpr so that we can easily check for this later
on.
Reviewers: rsmith, shafik
Reviewed By: rsmith
Subscribers: cfe-commits, jyknight, nickdesaulniers
Differential Revision: https://reviews.llvm.org/D53921
llvm-svn: 346455
This allows you to dump C++ code that spells bool instead of _Bool, leaves off the elaborated type specifiers when printing struct or class names, and other C-isms.
Fixes the -Wreorder issue and fixes the ast-dump-color.cpp test.
llvm-svn: 321310
This allows you to dump C++ code that spells bool instead of _Bool, leaves off the elaborated type specifiers when printing struct or class names, and other C-isms.
llvm-svn: 321223
the body of a function for the purposes of computing its storage
duration and deciding whether its initializer must be constant.
There are a number of problems in our current treatment of compound
literals. C specifies that a compound literal yields an l-value
referring to an object with either static or automatic storage
duration, depending on where it was written; in the latter case,
the literal object has a lifetime tied to the enclosing scope (much
like an ObjC block), not the enclosing full-expression. To get these
semantics fully correct in our current design, we would need to
collect compound literals on the ExprWithCleanups, just like we do
with ObjC blocks; we would probably also want to identify literals
like we do with materialized temporaries. But it gets stranger;
GCC adds compound literals to C++ as an extension, but makes them
r-values, which are generally assumed to have temporary storage
duration. Ignoring destructor ordering, the difference only matters
if the object's address escapes the full-expression, which for an
r-value can only happen with reference binding (which extends
temporaries) or array-to-pointer decay (which does not). GCC then
attempts to lock down on array-to-pointer decay in ad hoc ways.
Arguably a far superior language solution for C++ (and perhaps even
array r-values in C, which can occur in other ways) would be to
propagate lifetime extension through array-to-pointer decay, so
that initializing a pointer object to a decayed r-value array
extends the lifetime of the complete object containing the array.
But this would be a major change in semantics which arguably ought
to be blessed by the committee(s).
Anyway, I'm not fixing any of that in this patch; I did try, but
it got out of hand.
Fixes rdar://28949016.
llvm-svn: 285643
Currently, IR generation can't handle file-scope compound literals with
non-constant initializers in C++.
Fixes PR17415 (the first crash in the bug).
(We should probably change (T){1,2,3} to use the same codepath as T{1,2,3} in
C++ eventually, given that the semantics of the latter are actually defined by
the standard.)
llvm-svn: 191719
Previously, this compound literal expression (a GNU extension in C++):
(AggregateWithDtor){1, 2}
resulted in this AST:
`-CXXBindTemporaryExpr [...] 'struct Point' (CXXTemporary [...])
`-CompoundLiteralExpr [...] 'struct AggregateWithDtor'
`-CXXBindTemporaryExpr [...] 'struct AggregateWithDtor' (CXXTemporary [...])
`-InitListExpr [...] 'struct AggregateWithDtor'
|-IntegerLiteral [...] 'int' 1
`-IntegerLiteral [...] 'int' 2
Note the two CXXBindTemporaryExprs. The InitListExpr is really part of the
CompoundLiteralExpr, not an object in its own right. By introducing a new
entity initialization kind in Sema specifically for compound literals, we
avoid the treatment of the inner InitListExpr as a temporary.
`-CXXBindTemporaryExpr [...] 'struct Point' (CXXTemporary [...])
`-CompoundLiteralExpr [...] 'struct AggregateWithDtor'
`-InitListExpr [...] 'struct AggregateWithDtor'
|-IntegerLiteral [...] 'int' 1
`-IntegerLiteral [...] 'int' 2
llvm-svn: 181212
Fangrui Song