[os_log] Fix a CodeGen crash that occurs when arguments of struct, class, or complex types are passed to _builtin_os_log_format #158744
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class, or complex types are passed to _builtin_os_log_format This change fixes a crash in clang's CodeGen by ensuring that those arguments are ignored. rdar://139824423
llvmbot
added
clang
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@llvm/pr-subscribers-clang Author: Akira Hatanaka (ahatanak) ChangesThis change fixes a crash in clang's CodeGen by ensuring that those arguments are ignored. rdar://139824423 Full diff: https://github.com/llvm/llvm-project/pull/158744.diff 2 Files Affected:
diff --git a/clang/lib/AST/OSLog.cpp b/clang/lib/AST/OSLog.cpp
index 91f8410e89e86..d228d297dd2ca 100644
--- a/clang/lib/AST/OSLog.cpp
+++ b/clang/lib/AST/OSLog.cpp
@@ -70,22 +70,31 @@ class OSLogFormatStringHandler
bool HandlePrintfSpecifier(const analyze_printf::PrintfSpecifier &FS,
const char *StartSpecifier, unsigned SpecifierLen,
const TargetInfo &) override {
+ // Set the argument expression. Arguments of struct/class/complex types are
+ // ignored.
+ auto CheckAndSetArgExpr = [&](unsigned Idx, auto &ArgE) {
+ const Expr *E = Args[Idx];
+ if (E && (E->getType()->isRecordType() || E->getType()->isComplexType()))
+ return false;
+ ArgE = E;
+ return true;
+ };
+
if (!FS.consumesDataArgument() &&
FS.getConversionSpecifier().getKind() !=
clang::analyze_format_string::ConversionSpecifier::PrintErrno)
return true;
- ArgsData.emplace_back();
+ ArgData ArgD;
unsigned ArgIndex = FS.getArgIndex();
if (ArgIndex < Args.size())
- ArgsData.back().E = Args[ArgIndex];
+ if (!CheckAndSetArgExpr(ArgIndex, ArgD.E))
+ return true;
// First get the Kind
- ArgsData.back().Kind = getKind(FS.getConversionSpecifier().getKind());
- if (ArgsData.back().Kind != OSLogBufferItem::ErrnoKind &&
- !ArgsData.back().E) {
+ ArgD.Kind = getKind(FS.getConversionSpecifier().getKind());
+ if (ArgD.Kind != OSLogBufferItem::ErrnoKind && !ArgD.E) {
// missing argument
- ArgsData.pop_back();
return false;
}
@@ -97,10 +106,11 @@ class OSLogFormatStringHandler
case clang::analyze_format_string::OptionalAmount::NotSpecified: // "%s"
break;
case clang::analyze_format_string::OptionalAmount::Constant: // "%.16s"
- ArgsData.back().Size = precision.getConstantAmount();
+ ArgD.Size = precision.getConstantAmount();
break;
case clang::analyze_format_string::OptionalAmount::Arg: // "%.*s"
- ArgsData.back().Count = Args[precision.getArgIndex()];
+ if (!CheckAndSetArgExpr(precision.getArgIndex(), ArgD.Count))
+ return true;
break;
case clang::analyze_format_string::OptionalAmount::Invalid:
return false;
@@ -113,10 +123,11 @@ class OSLogFormatStringHandler
case clang::analyze_format_string::OptionalAmount::NotSpecified: // "%P"
return false; // length must be supplied with pointer format specifier
case clang::analyze_format_string::OptionalAmount::Constant: // "%.16P"
- ArgsData.back().Size = precision.getConstantAmount();
+ ArgD.Size = precision.getConstantAmount();
break;
case clang::analyze_format_string::OptionalAmount::Arg: // "%.*P"
- ArgsData.back().Count = Args[precision.getArgIndex()];
+ if (!CheckAndSetArgExpr(precision.getArgIndex(), ArgD.Count))
+ return true;
break;
case clang::analyze_format_string::OptionalAmount::Invalid:
return false;
@@ -125,22 +136,27 @@ class OSLogFormatStringHandler
}
default:
if (FS.getPrecision().hasDataArgument()) {
- ArgsData.back().Precision = Args[FS.getPrecision().getArgIndex()];
+ if (!CheckAndSetArgExpr(FS.getPrecision().getArgIndex(),
+ ArgD.Precision))
+ return true;
}
break;
}
if (FS.getFieldWidth().hasDataArgument()) {
- ArgsData.back().FieldWidth = Args[FS.getFieldWidth().getArgIndex()];
+ if (!CheckAndSetArgExpr(FS.getFieldWidth().getArgIndex(),
+ ArgD.FieldWidth))
+ return true;
}
if (FS.isSensitive())
- ArgsData.back().Flags |= OSLogBufferItem::IsSensitive;
+ ArgD.Flags |= OSLogBufferItem::IsSensitive;
else if (FS.isPrivate())
- ArgsData.back().Flags |= OSLogBufferItem::IsPrivate;
+ ArgD.Flags |= OSLogBufferItem::IsPrivate;
else if (FS.isPublic())
- ArgsData.back().Flags |= OSLogBufferItem::IsPublic;
+ ArgD.Flags |= OSLogBufferItem::IsPublic;
- ArgsData.back().MaskType = FS.getMaskType();
+ ArgD.MaskType = FS.getMaskType();
+ ArgsData.push_back(ArgD);
return true;
}
diff --git a/clang/test/CodeGenObjC/os_log.m b/clang/test/CodeGenObjC/os_log.m
index 837883ec4bb75..00229a746304c 100644
--- a/clang/test/CodeGenObjC/os_log.m
+++ b/clang/test/CodeGenObjC/os_log.m
@@ -13,6 +13,13 @@ + (id)m1;
C *c;
+struct S {
+ int a[4];
+};
+
+struct S s;
+_Complex float cf;
+
@class NSString;
extern __attribute__((visibility("default"))) NSString *GenString(void);
void os_log_pack_send(void *);
@@ -123,3 +130,19 @@ void test_builtin_os_log5(void *buf) {
__builtin_os_log_format(buf, "capabilities: %@", (0, GenString()));
os_log_pack_send(buf);
}
+
+// CHECK-LABEL: define void @test_builtin_os_log6(
+// CHECK: call void @__os_log_helper_1_0_0(
+
+void test_builtin_os_log6(void *buf) {
+ __builtin_os_log_format(buf, "%.*s %.*P %*.*f", s, s, s, s, s, s, s);
+}
+
+// CHECK-LABEL: define linkonce_odr hidden void @__os_log_helper_1_0_0(
+
+// CHECK-LABEL: define void @test_builtin_os_log7(
+// CHECK: call void @__os_log_helper_1_0_0(
+
+void test_builtin_os_log7(void *buf) {
+ __builtin_os_log_format(buf, "%.*s %.*P %*.*f", cf, cf, cf, cf, cf, cf, cf);
+}
|
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I repro'd the original problem at desk: "cannot compile this %0 yet" is a codegen diagnostic and the crash doesn't reproduce if I also pass -fsyntax-only. I understand that we have to do something regardless because you can turn off -Wnon-pod-varargs, but how come we get to codegen after an error was emitted? |
clang/lib/AST/OSLog.cpp
Outdated
| const char *StartSpecifier, unsigned SpecifierLen, | ||
| const TargetInfo &) override { | ||
| // Set the argument expression. Arguments of struct/class/complex types are | ||
| // ignored. |
There was a problem hiding this comment.
Is there any reason we can't diagnose this as an error? A priori, it seems no one can be doing this right now because it crashes clang. The layout is going to be super broken if we skip arguments.
We get to CodeGen because warnings aren't unrecoverable errors. |
apple-fcloutier
approved these changes
Sep 23, 2025
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/27/builds/16491 Here is the relevant piece of the build log for the reference |
ahatanaka
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to swiftlang/llvm-project
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Sep 23, 2025
…ass, or complex types are passed to _builtin_os_log_format (llvm#158744) This change fixes the crash in clang's CodeGen by erroring out in Sema if those arguments are passed. rdar://139824423
ahatanaka
pushed a commit
to swiftlang/llvm-project
that referenced
this pull request
Sep 23, 2025
…ass, or complex types are passed to _builtin_os_log_format (llvm#158744) This change fixes the crash in clang's CodeGen by erroring out in Sema if those arguments are passed. rdar://139824423
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This change fixes the crash in clang's CodeGen by erroring out in Sema if those arguments are passed.
rdar://139824423