[clang] [clang] Fix pretty-printing assume_aligned attributes (PR #67331)

[Balazs Benics via cfe-commits]

https://github.com/steakhal updated https://github.com/llvm/llvm-project/pull/67331

>From 988dcf4f568a58d9b1127b2adf8890a7c7867ac5 Mon Sep 17 00:00:00 2001
From: Balazs Benics <benicsbalazs at gmail.com>
Date: Mon, 25 Sep 2023 15:37:34 +0200
Subject: [PATCH] [clang] Fix pretty-printing assume_aligned attributes

Inside `writePrettyPrintFunction()`, we check if we need to emit the
given argument:
```C++
if (!arg->isOptional() || arg->getIsOmitted() == "false") {
    FoundNonOptArg = true;
    continue;
}
```
For the `AssumeAligned` attribute, the second argument was optional, but
the `getIsOmitted()` returned `false`, thus we treated this argument as
**non-optional** in the end because of that disjunction.

It was because `getIsOmitted()` did not account for `Expr *` type, and
returned `false` on the fallthrough branch.

Fixes #67156
---
 clang/test/AST/attr-print-emit.cpp        | 6 ++++++
 clang/utils/TableGen/ClangAttrEmitter.cpp | 7 ++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/clang/test/AST/attr-print-emit.cpp b/clang/test/AST/attr-print-emit.cpp
index cc7413baf10e87a..8c48eb92daba5ee 100644
--- a/clang/test/AST/attr-print-emit.cpp
+++ b/clang/test/AST/attr-print-emit.cpp
@@ -2,6 +2,12 @@
 // RUN: %clang -emit-ast -o %t.ast %s
 // RUN: %clang_cc1 %t.ast -ast-print | FileCheck %s
 
+// CHECK: void *aa() __attribute__((assume_aligned(64)));
+void *aa() __attribute__((assume_aligned(64)));
+
+// CHECK: void *aa2() __attribute__((assume_aligned(64, 8)));
+void *aa2() __attribute__((assume_aligned(64, 8)));
+
 // CHECK: void xla(int a) __attribute__((xray_log_args(1)));
 void xla(int a) __attribute__((xray_log_args(1)));
 
diff --git a/clang/utils/TableGen/ClangAttrEmitter.cpp b/clang/utils/TableGen/ClangAttrEmitter.cpp
index 7ea09058c3d39f2..f036656a7685fd6 100644
--- a/clang/utils/TableGen/ClangAttrEmitter.cpp
+++ b/clang/utils/TableGen/ClangAttrEmitter.cpp
@@ -320,11 +320,12 @@ namespace {
     }
 
     std::string getIsOmitted() const override {
-      if (type == "IdentifierInfo *")
+      StringRef T = type;
+      if (T == "IdentifierInfo *" || T == "Expr *")
         return "!get" + getUpperName().str() + "()";
-      if (type == "TypeSourceInfo *")
+      if (T == "TypeSourceInfo *")
         return "!get" + getUpperName().str() + "Loc()";
-      if (type == "ParamIdx")
+      if (T == "ParamIdx")
         return "!get" + getUpperName().str() + "().isValid()";
       return "false";
     }