[Lldb-commits] [lldb] [lldb] Fix TypeSystemClang::GetBasicTypeEnumeration for 128-bit int types (PR #162278)

[via lldb-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Matej Košík (sedymrak)

<details>
<summary>Changes</summary>

When we take the following C program:
```
int main() {
  return 0;
}
```
and create a statically-linked executable from it:
```
clang -static -g -o main main.c
```
Then we can observe the following `lldb` behavior:
```
$ lldb
(lldb) target create main
Current executable set to '.../main' (x86_64).
(lldb) breakpoint set --name main
Breakpoint 1: where = main`main + 11 at main.c:2:3, address = 0x000000000022aa7b
(lldb) process launch
Process 3773637 launched: '/home/me/tmp/built-in/main' (x86_64)
Process 3773637 stopped
* thread #<!-- -->1, name = 'main', stop reason = breakpoint 1.1
    frame #<!-- -->0: 0x000000000022aa7b main`main at main.c:2:3
   1   	int main() {
-> 2   	  return 0;
   3   	}
(lldb) script lldb.debugger.GetSelectedTarget().FindFirstType("__int128").size
0
(lldb) script lldb.debugger.GetSelectedTarget().FindFirstType("unsigned __int128").size
0
(lldb) quit
```
The value return by the `SBTarget::FindFirstType` method is wrong for the `__int128` and `unsigned __int128` basic types.

The proposed changes make the `TypeSystemClang::GetBasicTypeEnumeration` method consistent with `gcc` and `clang` C [language extension](https://gcc.gnu.org/onlinedocs/gcc/_005f_005fint128.html) related to 128-bit integer types as well as with the `BuiltinType::getName` method in the LLVM codebase itself.

When the above change is applied, the behavior of the `lldb` changes in the following (desired) way:
```
$ lldb
(lldb) target create main
Current executable set to '.../main' (x86_64).
(lldb) breakpoint set --name main
Breakpoint 1: where = main`main + 11 at main.c:2:3, address = 0x000000000022aa7b
(lldb) process launch
Process 3773637 launched: '/home/me/tmp/built-in/main' (x86_64)
Process 3773637 stopped
* thread #<!-- -->1, name = 'main', stop reason = breakpoint 1.1
    frame #<!-- -->0: 0x000000000022aa7b main`main at main.c:2:3
   1   	int main() {
-> 2   	  return 0;
   3   	}
(lldb) script lldb.debugger.GetSelectedTarget().FindFirstType("__int128").size
16
(lldb) script lldb.debugger.GetSelectedTarget().FindFirstType("unsigned __int128").size
16
(lldb) quit
```

---
Full diff: https://github.com/llvm/llvm-project/pull/162278.diff


2 Files Affected:

- (modified) lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp (+2-2) 
- (modified) lldb/unittests/Symbol/TestTypeSystemClang.cpp (+2-2) 


``````````diff
diff --git a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
index 21c265ede0bc5..1a574c97d9e46 100644
--- a/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
+++ b/lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp
@@ -849,8 +849,8 @@ lldb::BasicType TypeSystemClang::GetBasicTypeEnumeration(llvm::StringRef name) {
       {"unsigned long long int", eBasicTypeUnsignedLongLong},
 
       // "int128"
-      {"__int128_t", eBasicTypeInt128},
-      {"__uint128_t", eBasicTypeUnsignedInt128},
+      {"__int128", eBasicTypeInt128},
+      {"unsigned __int128", eBasicTypeUnsignedInt128},
 
       // "bool"
       {"bool", eBasicTypeBool},
diff --git a/lldb/unittests/Symbol/TestTypeSystemClang.cpp b/lldb/unittests/Symbol/TestTypeSystemClang.cpp
index f673cceae00dd..df507739d5c73 100644
--- a/lldb/unittests/Symbol/TestTypeSystemClang.cpp
+++ b/lldb/unittests/Symbol/TestTypeSystemClang.cpp
@@ -159,9 +159,9 @@ TEST_F(TestTypeSystemClang, TestGetBasicTypeFromName) {
             GetBasicQualType("unsigned long long"));
   EXPECT_EQ(GetBasicQualType(eBasicTypeUnsignedLongLong),
             GetBasicQualType("unsigned long long int"));
-  EXPECT_EQ(GetBasicQualType(eBasicTypeInt128), GetBasicQualType("__int128_t"));
+  EXPECT_EQ(GetBasicQualType(eBasicTypeInt128), GetBasicQualType("__int128"));
   EXPECT_EQ(GetBasicQualType(eBasicTypeUnsignedInt128),
-            GetBasicQualType("__uint128_t"));
+            GetBasicQualType("unsigned __uint128"));
   EXPECT_EQ(GetBasicQualType(eBasicTypeVoid), GetBasicQualType("void"));
   EXPECT_EQ(GetBasicQualType(eBasicTypeBool), GetBasicQualType("bool"));
   EXPECT_EQ(GetBasicQualType(eBasicTypeFloat), GetBasicQualType("float"));

``````````

</details>


https://github.com/llvm/llvm-project/pull/162278