================
@@ -0,0 +1,64 @@
+// Verify that -mloadtime-comment-vars= diagnoses named C variables it cannot
+// preserve. The diagnostics are produced by Sema and fire even with
+// -fsyntax-only.
+//
+// Covered cases:
+// - volatile-qualified pointer (char *volatile)
+// - pointer-to-volatile character (volatile char *)
+// - volatile character array (volatile char[])
+// - thread-local variable (__thread, not static storage duration)
+// - pointer not initialized directly with a string literal
+// - name-matched variables of an unsupported type (int, unsigned char)
+// - valid const char array — no diagnostic
+// - a preserved variable counts as used: no -Wunused-const-variable for it,
+// while an unlisted static const variable still warns
+//
+// The NONAIX scenario invokes cc1 directly for a non-AIX target: the option
+// is rejected with an error.
+
+// RUN: %clang_cc1 -triple powerpc64-ibm-aix -Wunused-const-variable \
+// RUN:
-mloadtime-comment-vars=vol_ptr,vol_char,vol_arr,tls_ptr,ind_ptr,const_arr,lfn,kept,notchar,ustr
\
----------------
tonykuttai wrote:
```
❯ cat t.c
void h(void) {
static char lfn[] = "@(#) lfn";
(void)lfn;
}
❯ clang -cc1 -triple powerpc64-ibm-aix -ast-dump t.c
.....
`-FunctionDecl 0x79d719f000 <t.c:1:1, line:4:1> line:1:6 h 'void (void)'
external-linkage
`-CompoundStmt 0x79d719f2a8 <col:14, line:4:1> FPEvalMethod=1
|-DeclStmt 0x79d719f220 <line:2:3, col:33>
| `-VarDecl 0x79d719f160 <col:3, col:23> col:15 used lfn 'char[9]' static
cinit
| `-StringLiteral 0x79d719f200 <col:23> 'char[9]' "@(#) lfn"
`-CStyleCastExpr 0x79d719f280 <line:3:3, col:9> 'void' <ToVoid>
`-ImplicitCastExpr 0x79d719f268 <col:9> 'char *' <ArrayToPointerDecay>
part_of_explicit_cast
`-DeclRefExpr 0x79d719f238 <col:9> 'char[9]' lvalue Var 0x79d719f160
'lfn' 'char[9]'
```
Sema matches the `ASTNameGenerator` returned named, so `lfn` matches. But it
uses `h.lfn` in Clang codegen though.
```
❯ clang -cc1 -triple powerpc64-ibm-aix -emit-llvm -o - t.c
-mloadtime-comment-vars=lfn
t.c:2:15: warning: 'lfn' named in '-mloadtime-comment-vars=' is a
function-local variable and will not be preserved [-Wloadtime-comment-var]
2 | static char lfn[] = "@(#) lfn";
| ^
; ModuleID = 't.c'
source_filename = "t.c"
target datalayout =
"E-m:a-Fi64-i64:64-i128:128-n32:64-f64:32:64-S128-v256:256:256-v512:512:512"
target triple = "powerpc64-ibm-aix"
@h.lfn = internal global [9 x i8] c"@(#) lfn\00", align 1
; Function Attrs: noinline nounwind optnone
define void @h() #0 {
entry:
ret void
}
attributes #0 = { noinline nounwind optnone "no-trapping-math"="true"
"stack-protector-buffer-size"="8" }
!llvm.ident = !{!0}
!0 = !{!"clang version 24.0.0git"}
1 warning generated.
```
https://github.com/llvm/llvm-project/pull/187986
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