forked from llvm/llvm-project
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[lldb][TypeSystemClang] Create VLAs of explicitly 0-size as ConstantA…
…rrayType (llvm#100710) Depends on llvm#100674 Currently, we treat VLAs declared as `int[]` and `int[0]` identically. I.e., we create them as `IncompleteArrayType`s. However, the `DW_AT_count` for `int[0]` *does* exist, and is retrievable without an execution context. This patch decouples the notion of "has 0 elements" from "has no known `DW_AT_count`". This aligns with how Clang represents `int[0]` in the AST (it treats it as a `ConstantArrayType` of 0 size). This issue was surfaced when adapting LLDB to llvm#93069. There, the `__compressed_pair_padding` type has a `char[0]` member. If we previously got the `__compressed_pair_padding` out of a module (where clang represents `char[0]` as a `ConstantArrayType`), and try to merge the AST with one we got from DWARF (where LLDB used to represent `char[0]` as an `IncompleteArrayType`), the AST structural equivalence check fails, resulting in silent ASTImporter failures. This manifested in a failure in `TestNonModuleTypeSeparation.py`. **Implementation** 1. Adjust `ParseChildArrayInfo` to store the element counts of each VLA dimension as an `optional<uint64_t>`, instead of a regular `uint64_t`. So when we pass this down to `CreateArrayType`, we have a better heuristic for what is an `IncompleteArrayType`. 2. In `TypeSystemClang::GetBitSize`, if we encounter a `ConstantArrayType` simply return the size that it was created with. If we couldn't determine the authoritative bound from DWARF during parsing, we would've created an `IncompleteArrayType`. This ensures that `GetBitSize` on arrays with `DW_AT_count 0x0` returns `0` (whereas previously it would've returned a `std::nullopt`, causing that `FieldDecl` to just get dropped during printing)
- Loading branch information
1 parent
616bfc9
commit 0b964a1
Showing
7 changed files
with
127 additions
and
35 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,80 @@ | ||
| // RUN: %clangxx_host -gdwarf -std=c++11 -o %t %s | ||
| // RUN: %lldb %t \ | ||
| // RUN: -o run \ | ||
| // RUN: -o "frame var --show-types f" \ | ||
| // RUN: -o "frame var vla0" \ | ||
| // RUN: -o "frame var fla0" \ | ||
| // RUN: -o "frame var fla1" \ | ||
| // RUN: -o "frame var vla01" \ | ||
| // RUN: -o "frame var vla10" \ | ||
| // RUN: -o "frame var vlaN" \ | ||
| // RUN: -o "frame var vlaNM" \ | ||
| // RUN: -o exit | FileCheck %s | ||
|
|
||
| struct Foo { | ||
| static constexpr int n = 1; | ||
| int m_vlaN[n]; | ||
|
|
||
| int m_vla0[0]; | ||
| }; | ||
|
|
||
| int main() { | ||
| Foo f; | ||
| f.m_vlaN[0] = 60; | ||
|
|
||
| // CHECK: (lldb) frame var --show-types f | ||
| // CHECK-NEXT: (Foo) f = { | ||
| // CHECK-NEXT: (int[1]) m_vlaN = { | ||
| // CHECK-NEXT: (int) [0] = 60 | ||
| // CHECK-NEXT: } | ||
| // CHECK-NEXT: (int[0]) m_vla0 = {} | ||
| // CHECK-NEXT: } | ||
|
|
||
| int vla0[0] = {}; | ||
|
|
||
| // CHECK: (lldb) frame var vla0 | ||
| // CHECK-NEXT: (int[0]) vla0 = {} | ||
|
|
||
| int fla0[] = {}; | ||
|
|
||
| // CHECK: (lldb) frame var fla0 | ||
| // CHECK-NEXT: (int[0]) fla0 = {} | ||
|
|
||
| int fla1[] = {42}; | ||
|
|
||
| // CHECK: (lldb) frame var fla1 | ||
| // CHECK-NEXT: (int[1]) fla1 = ([0] = 42) | ||
|
|
||
| int vla01[0][1]; | ||
|
|
||
| // CHECK: (lldb) frame var vla01 | ||
| // CHECK-NEXT: (int[0][1]) vla01 = {} | ||
|
|
||
| int vla10[1][0]; | ||
|
|
||
| // CHECK: (lldb) frame var vla10 | ||
| // CHECK-NEXT: (int[1][0]) vla10 = ([0] = int[0] | ||
|
|
||
| int n = 3; | ||
| int vlaN[n]; | ||
| for (int i = 0; i < n; ++i) | ||
| vlaN[i] = -i; | ||
|
|
||
| // CHECK: (lldb) frame var vlaN | ||
| // CHECK-NEXT: (int[]) vlaN = ([0] = 0, [1] = -1, [2] = -2) | ||
|
|
||
| int m = 2; | ||
| int vlaNM[n][m]; | ||
| for (int i = 0; i < n; ++i) | ||
| for (int j = 0; j < m; ++j) | ||
| vlaNM[i][j] = i + j; | ||
|
|
||
| // FIXME: multi-dimensional VLAs aren't well supported | ||
| // CHECK: (lldb) frame var vlaNM | ||
| // CHECK-NEXT: (int[][]) vlaNM = { | ||
| // CHECK-NEXT: [0] = ([0] = 0, [1] = 1, [2] = 1) | ||
| // CHECK-NEXT: [1] = ([0] = 1, [1] = 1, [2] = 2) | ||
| // CHECK-NEXT: } | ||
|
|
||
| __builtin_debugtrap(); | ||
| } |