Currently APValues are dumped as a single string. This becomes quickly
completely unreadable since APValue is a tree-like structure. Even a simple
example is not pretty:
struct S { int arr[4]; float f; };
constexpr S s = { .arr = {1,2}, .f = 3.1415f };
// Struct fields: Array: Int: 1, Int: 2, 2 x Int: 0, Float: 3.141500e+00
With this patch this becomes:
-Struct
|-field: Array size=4
| |-elements: Int 1, Int 2
| `-filler: 2 x Int 0
`-field: Float 3.141500e+00
Additionally APValues are currently only dumped as part of visiting a
ConstantExpr. This patch also dump the value of the initializer of constexpr
variable declarations:
constexpr int foo(int a, int b) { return a + b - 42; }
constexpr int a = 1, b = 2;
constexpr int c = foo(a, b) > 0 ? foo(a, b) : foo(b, a);
// VarDecl 0x62100008aec8 <col:3, col:57> col:17 c 'const int' constexpr cinit
// |-value: Int -39
// `-ConditionalOperator 0x62100008b4d0 <col:21, col:57> 'int'
// <snip>
Do the above by moving the dump functions to TextNodeDumper which already has
the machinery to display trees. The cases APValue::LValue, APValue::MemberPointer
and APValue::AddrLabelDiff are left as they were before (unimplemented).
We try to display multiple elements on the same line if they are considered to
be "simple". This is to avoid wasting large amounts of vertical space in an
example like:
constexpr int arr[8] = {0,1,2,3,4,5,6,7};
// VarDecl 0x62100008bb78 <col:3, col:42> col:17 arr 'int const[8]' constexpr cinit
// |-value: Array size=8
// | |-elements: Int 0, Int 1, Int 2, Int 3
// | `-elements: Int 4, Int 5, Int 6, Int 7
Differential Revision: https://reviews.llvm.org/D83183
Reviewed By: aaron.ballman
The serialization of ConstantExpr has currently a number of problems:
- Some fields are just not serialized (ConstantExprBits.APValueKind and
ConstantExprBits.IsImmediateInvocation).
- ASTStmtReader::VisitConstantExpr forgets to add the trailing APValue
to the list of objects to be destroyed when the APValue needs cleanup.
While we are at it, bring the serialization of ConstantExpr more in-line
with what is done with the other expressions by doing the following NFCs:
- Get rid of ConstantExpr::DefaultInit. It is better to not initialize
the fields of an empty ConstantExpr since this will allow msan to
detect if a field was not deserialized.
- Move the initialization of the fields of ConstantExpr to the constructor;
ConstantExpr::Create allocates the memory and ConstantExpr::ConstantExpr
is responsible for the initialization.
Review after commit since this is a straightforward mechanical fix
similar to the other serialization fixes.
Bruno Ricci