[clang] 35737df - [Clang][AArch64][ARM] Unaligned Access Warning Added
Mubashar Ahmad via cfe-commits
cfe-commits at lists.llvm.org
Thu Jan 20 06:13:29 PST 2022
Author: Mubashar Ahmad
Date: 2022-01-20T14:12:49Z
New Revision: 35737df4dcd28534bd3090157c224c19b501278a
URL: https://github.com/llvm/llvm-project/commit/35737df4dcd28534bd3090157c224c19b501278a
DIFF: https://github.com/llvm/llvm-project/commit/35737df4dcd28534bd3090157c224c19b501278a.diff
LOG: [Clang][AArch64][ARM] Unaligned Access Warning Added
Added warning for potential cases of
unaligned access when option
-mno-unaligned-access has been specified
Differential Revision: https://reviews.llvm.org/D116221
Added:
clang/test/Sema/test-wunaligned-access.c
clang/test/Sema/test-wunaligned-access.cpp
Modified:
clang/include/clang/Basic/DiagnosticASTKinds.td
clang/include/clang/Basic/DiagnosticGroups.td
clang/lib/AST/RecordLayoutBuilder.cpp
clang/lib/Driver/ToolChains/Arch/AArch64.cpp
clang/lib/Driver/ToolChains/Arch/AArch64.h
clang/lib/Driver/ToolChains/Arch/ARM.cpp
clang/lib/Driver/ToolChains/Clang.cpp
Removed:
################################################################################
diff --git a/clang/include/clang/Basic/DiagnosticASTKinds.td b/clang/include/clang/Basic/DiagnosticASTKinds.td
index d788c85179142..a89bdff1a10c2 100644
--- a/clang/include/clang/Basic/DiagnosticASTKinds.td
+++ b/clang/include/clang/Basic/DiagnosticASTKinds.td
@@ -590,4 +590,9 @@ def warn_padded_struct_size : Warning<
InGroup<Padded>, DefaultIgnore;
def warn_unnecessary_packed : Warning<
"packed attribute is unnecessary for %0">, InGroup<Packed>, DefaultIgnore;
+
+// -Wunaligned-access
+def warn_unaligned_access : Warning<
+ "field %1 within %0 is less aligned than %2 and is usually due to %0 being "
+ "packed, which can lead to unaligned accesses">, InGroup<UnalignedAccess>, DefaultIgnore;
}
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index 1bc879a68a8c7..608e16147b1cd 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -543,6 +543,7 @@ def ExplicitInitializeCall : DiagGroup<"explicit-initialize-call">;
def OrderedCompareFunctionPointers : DiagGroup<"ordered-compare-function-pointers">;
def Packed : DiagGroup<"packed">;
def Padded : DiagGroup<"padded">;
+def UnalignedAccess : DiagGroup<"unaligned-access">;
def PessimizingMove : DiagGroup<"pessimizing-move">;
def ReturnStdMove : DiagGroup<"return-std-move">;
diff --git a/clang/lib/AST/RecordLayoutBuilder.cpp b/clang/lib/AST/RecordLayoutBuilder.cpp
index 3e39ec1c718d1..61a30ead165ef 100644
--- a/clang/lib/AST/RecordLayoutBuilder.cpp
+++ b/clang/lib/AST/RecordLayoutBuilder.cpp
@@ -2021,6 +2021,7 @@ void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
CharUnits UnpackedFieldAlign =
!DefaultsToAIXPowerAlignment ? FieldAlign : PreferredAlign;
CharUnits UnpackedFieldOffset = FieldOffset;
+ CharUnits OriginalFieldAlign = UnpackedFieldAlign;
if (FieldPacked) {
FieldAlign = CharUnits::One();
@@ -2105,6 +2106,22 @@ void ItaniumRecordLayoutBuilder::LayoutField(const FieldDecl *D,
// Remember max struct/class ABI-specified alignment.
UnadjustedAlignment = std::max(UnadjustedAlignment, FieldAlign);
UpdateAlignment(FieldAlign, UnpackedFieldAlign, PreferredAlign);
+
+ // For checking the alignment of inner fields against
+ // the alignment of its parent record.
+ if (const RecordDecl *RD = D->getParent()) {
+ // Check if packed attribute or pragma pack is present.
+ if (RD->hasAttr<PackedAttr>() || !MaxFieldAlignment.isZero())
+ if (FieldAlign < OriginalFieldAlign)
+ if (D->getType()->isRecordType()) {
+ // If the offset is a multiple of the alignment of
+ // the type, raise the warning.
+ // TODO: Takes no account the alignment of the outer struct
+ if (FieldOffset % OriginalFieldAlign != 0)
+ Diag(D->getLocation(), diag::warn_unaligned_access)
+ << Context.getTypeDeclType(RD) << D->getName() << D->getType();
+ }
+ }
}
void ItaniumRecordLayoutBuilder::FinishLayout(const NamedDecl *D) {
diff --git a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
index 9ffb5d73b2aad..89a77a368ef02 100644
--- a/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/AArch64.cpp
@@ -221,6 +221,7 @@ getAArch64MicroArchFeaturesFromMcpu(const Driver &D, StringRef Mcpu,
void aarch64::getAArch64TargetFeatures(const Driver &D,
const llvm::Triple &Triple,
const ArgList &Args,
+ llvm::opt::ArgStringList &CmdArgs,
std::vector<StringRef> &Features,
bool ForAS) {
Arg *A;
@@ -464,10 +465,16 @@ void aarch64::getAArch64TargetFeatures(const Driver &D,
if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
options::OPT_munaligned_access)) {
- if (A->getOption().matches(options::OPT_mno_unaligned_access))
+ if (A->getOption().matches(options::OPT_mno_unaligned_access)) {
Features.push_back("+strict-align");
- } else if (Triple.isOSOpenBSD())
+ if (!ForAS)
+ CmdArgs.push_back("-Wunaligned-access");
+ }
+ } else if (Triple.isOSOpenBSD()) {
Features.push_back("+strict-align");
+ if (!ForAS)
+ CmdArgs.push_back("-Wunaligned-access");
+ }
if (Args.hasArg(options::OPT_ffixed_x1))
Features.push_back("+reserve-x1");
diff --git a/clang/lib/Driver/ToolChains/Arch/AArch64.h b/clang/lib/Driver/ToolChains/Arch/AArch64.h
index d47c402d4a42d..0cdc2ec725e02 100644
--- a/clang/lib/Driver/ToolChains/Arch/AArch64.h
+++ b/clang/lib/Driver/ToolChains/Arch/AArch64.h
@@ -22,6 +22,7 @@ namespace aarch64 {
void getAArch64TargetFeatures(const Driver &D, const llvm::Triple &Triple,
const llvm::opt::ArgList &Args,
+ llvm::opt::ArgStringList &CmdArgs,
std::vector<llvm::StringRef> &Features,
bool ForAS);
diff --git a/clang/lib/Driver/ToolChains/Arch/ARM.cpp b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
index 4013cf230026b..1055d7800b63e 100644
--- a/clang/lib/Driver/ToolChains/Arch/ARM.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/ARM.cpp
@@ -769,10 +769,12 @@ void arm::getARMTargetFeatures(const Driver &D, const llvm::Triple &Triple,
}
// Kernel code has more strict alignment requirements.
- if (KernelOrKext)
+ if (KernelOrKext) {
Features.push_back("+strict-align");
- else if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
- options::OPT_munaligned_access)) {
+ if (!ForAS)
+ CmdArgs.push_back("-Wunaligned-access");
+ } else if (Arg *A = Args.getLastArg(options::OPT_mno_unaligned_access,
+ options::OPT_munaligned_access)) {
if (A->getOption().matches(options::OPT_munaligned_access)) {
// No v6M core supports unaligned memory access (v6M ARM ARM A3.2).
if (Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v6m)
@@ -781,8 +783,11 @@ void arm::getARMTargetFeatures(const Driver &D, const llvm::Triple &Triple,
// access either.
else if (Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v8m_baseline)
D.Diag(diag::err_target_unsupported_unaligned) << "v8m.base";
- } else
+ } else {
Features.push_back("+strict-align");
+ if (!ForAS)
+ CmdArgs.push_back("-Wunaligned-access");
+ }
} else {
// Assume pre-ARMv6 doesn't support unaligned accesses.
//
@@ -801,14 +806,23 @@ void arm::getARMTargetFeatures(const Driver &D, const llvm::Triple &Triple,
int VersionNum = getARMSubArchVersionNumber(Triple);
if (Triple.isOSDarwin() || Triple.isOSNetBSD()) {
if (VersionNum < 6 ||
- Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v6m)
+ Triple.getSubArch() == llvm::Triple::SubArchType::ARMSubArch_v6m) {
Features.push_back("+strict-align");
+ if (!ForAS)
+ CmdArgs.push_back("-Wunaligned-access");
+ }
} else if (Triple.isOSLinux() || Triple.isOSNaCl() ||
Triple.isOSWindows()) {
- if (VersionNum < 7)
+ if (VersionNum < 7) {
Features.push_back("+strict-align");
- } else
+ if (!ForAS)
+ CmdArgs.push_back("-Wunaligned-access");
+ }
+ } else {
Features.push_back("+strict-align");
+ if (!ForAS)
+ CmdArgs.push_back("-Wunaligned-access");
+ }
}
// llvm does not support reserving registers in general. There is support
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 253c52cf0ba85..96d949be17eea 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -346,7 +346,8 @@ static void getTargetFeatures(const Driver &D, const llvm::Triple &Triple,
case llvm::Triple::aarch64:
case llvm::Triple::aarch64_32:
case llvm::Triple::aarch64_be:
- aarch64::getAArch64TargetFeatures(D, Triple, Args, Features, ForAS);
+ aarch64::getAArch64TargetFeatures(D, Triple, Args, CmdArgs, Features,
+ ForAS);
break;
case llvm::Triple::x86:
case llvm::Triple::x86_64:
diff --git a/clang/test/Sema/test-wunaligned-access.c b/clang/test/Sema/test-wunaligned-access.c
new file mode 100644
index 0000000000000..55c2149634d1a
--- /dev/null
+++ b/clang/test/Sema/test-wunaligned-access.c
@@ -0,0 +1,516 @@
+// RUN: %clang_cc1 %s -triple=armv7-none-none-eabi -verify -Wunaligned-access -S -emit-llvm
+// REQUIRES: arm-registered-target
+//
+// This test suite tests the warning triggered by the -Wunaligned-access option.
+// The warning occurs when a struct or other type of record contains a field
+// that is itself a record. The outer record must be a packed structure, while
+// while the inner record must be unpacked. This is the fundamental condition
+// for the warning to be triggered. Some of these tests may have three layers.
+//
+// The command line option -fsyntax-only is not used as Clang needs to be
+// forced to layout the structs used in this test.
+// The triple in the command line above is used for the assumptions about
+// size and alignment of types.
+
+// Set 1
+struct T1 {
+ char a;
+ int b;
+};
+
+struct __attribute__((packed)) U1 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct U1' is less aligned than 'struct T1' and is usually due to 'struct U1' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((packed)) U2 {
+ char a;
+ struct T1 b __attribute__((aligned(2))); // expected-warning {{field b within 'struct U2' is less aligned than 'struct T1' and is usually due to 'struct U2' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((packed)) U3 {
+ char a;
+ struct T1 b __attribute__((aligned(4)));
+ int c;
+};
+
+struct __attribute__((aligned(2))) U4 {
+ char a;
+ struct T1 b;
+ int c;
+};
+
+struct U5 {
+ char a;
+ struct T1 b;
+ int c;
+};
+
+struct U6 {
+ char a;
+ int b;
+ struct T1 c __attribute__((aligned(2)));
+};
+
+struct __attribute__((packed)) U7 {
+ short a;
+ short b;
+ char c;
+ struct T1 d; // expected-warning {{field d within 'struct U7' is less aligned than 'struct T1' and is usually due to 'struct U7' being packed, which can lead to unaligned accesses}}
+};
+
+struct U8 {
+ short a;
+ short b;
+ char c;
+ struct T1 d;
+};
+
+struct __attribute__((packed)) U9 {
+ short a;
+ short b;
+ char c;
+ struct T1 d __attribute__((aligned(4)));
+};
+
+struct __attribute__((packed)) U10 {
+ short a;
+ short b;
+ char c;
+ struct T1 d __attribute__((aligned(2))); // expected-warning {{field d within 'struct U10' is less aligned than 'struct T1' and is usually due to 'struct U10' being packed, which can lead to unaligned accesses}}
+};
+
+struct __attribute__((aligned(2))) U11 {
+ short a;
+ short b;
+ char c;
+ struct T1 d;
+};
+
+// Set 2
+#pragma pack(push, 1)
+
+struct U12 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct U12' is less aligned than 'struct T1' and is usually due to 'struct U12' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((packed)) U13 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct U13' is less aligned than 'struct T1' and is usually due to 'struct U13' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((packed)) U14 {
+ char a;
+ struct T1 b __attribute__((aligned(4))); // expected-warning {{field b within 'struct U14' is less aligned than 'struct T1' and is usually due to 'struct U14' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((aligned(2))) U15 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct U15' is less aligned than 'struct T1' and is usually due to 'struct U15' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct U16 {
+ char a;
+ char b;
+ short c;
+ struct T1 d;
+};
+
+struct U17 {
+ char a;
+ char b;
+ short c;
+ struct T1 d __attribute__((aligned(4)));
+};
+
+struct __attribute__((packed)) U18 {
+ char a;
+ short b;
+ struct T1 c __attribute__((aligned(4))); // expected-warning {{field c within 'struct U18' is less aligned than 'struct T1' and is usually due to 'struct U18' being packed, which can lead to unaligned accesses}}
+};
+
+struct __attribute__((aligned(4))) U19 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct U19' is less aligned than 'struct T1' and is usually due to 'struct U19' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((aligned(4))) U20 {
+ char a[4];
+ struct T1 b;
+ int c;
+};
+
+struct U21 {
+ char a;
+ short c;
+ struct T1 d; // expected-warning {{field d within 'struct U21' is less aligned than 'struct T1' and is usually due to 'struct U21' being packed, which can lead to unaligned accesses}}
+};
+
+struct U22 {
+ char a;
+ short c;
+ struct T1 d __attribute__((aligned(4))); // expected-warning {{field d within 'struct U22' is less aligned than 'struct T1' and is usually due to 'struct U22' being packed, which can lead to unaligned accesses}}
+};
+
+#pragma pack(pop)
+
+// Set 3
+#pragma pack(push, 2)
+
+struct __attribute__((packed)) U23 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct U23' is less aligned than 'struct T1' and is usually due to 'struct U23' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct U24 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct U24' is less aligned than 'struct T1' and is usually due to 'struct U24' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct U25 {
+ char a;
+ char b;
+ short c;
+ struct T1 d;
+};
+
+struct U26 {
+ char a;
+ char b;
+ short c;
+ struct T1 d;
+};
+
+#pragma pack(pop)
+
+// Set 4
+
+struct __attribute__((packed)) T2 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct T2' is less aligned than 'struct T1' and is usually due to 'struct T2' being packed, which can lead to unaligned accesses}}
+};
+
+struct T3 {
+ char a;
+ struct T1 b;
+};
+
+struct __attribute__((packed)) U27 {
+ char a;
+ struct T2 b;
+ int c;
+};
+
+struct U28 {
+ char a;
+ char _p[2];
+ struct T2 b;
+ int c;
+};
+
+struct U29 {
+ char a;
+ struct T3 b;
+ int c;
+};
+
+struct __attribute__((packed)) U30 {
+ char a;
+ struct T3 b; // expected-warning {{field b within 'struct U30' is less aligned than 'struct T3' and is usually due to 'struct U30' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((packed)) U31 {
+ char a;
+ struct T2 b __attribute__((aligned(4)));
+};
+
+struct __attribute__((packed)) U32 {
+ char a;
+ char b;
+ char c;
+ char d;
+ struct T3 e;
+};
+
+struct __attribute__((packed)) U33 {
+ char a;
+ char b;
+ char c;
+ char d;
+ struct T2 e __attribute__((aligned(4)));
+};
+
+struct __attribute__((packed)) U34 {
+ char a;
+ struct T1 b __attribute__((packed)); // expected-warning {{field b within 'struct U34' is less aligned than 'struct T1' and is usually due to 'struct U34' being packed, which can lead to unaligned accesses}}
+ struct T2 c;
+};
+
+struct __attribute__((packed)) U35 {
+ char a;
+ struct T4 {
+ char b;
+ struct T1 c;
+ } d; // expected-warning {{field d within 'struct U35' is less aligned than 'struct T4' and is usually due to 'struct U35' being packed, which can lead to unaligned accesses}}
+};
+
+// Set 5
+
+#pragma pack(push, 1)
+struct T5 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct T5' is less aligned than 'struct T1' and is usually due to 'struct T5' being packed, which can lead to unaligned accesses}}
+};
+#pragma pack(pop)
+
+#pragma pack(push, 1)
+struct U36 {
+ char a;
+ struct T5 b;
+ int c;
+};
+
+struct U37 {
+ char a;
+ struct T3 b; // expected-warning {{field b within 'struct U37' is less aligned than 'struct T3' and is usually due to 'struct U37' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+#pragma pack(pop)
+struct U38 {
+ char a;
+ struct T5 b __attribute__((aligned(4)));
+ int c;
+};
+
+#pragma pack(push, 1)
+
+#pragma pack(push, 4)
+struct U39 {
+ char a;
+ struct T5 b;
+ int c;
+};
+#pragma pack(pop)
+
+#pragma pack(pop)
+
+// Set 6
+
+struct __attribute__((packed)) A1 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct A1' is less aligned than 'struct T1' and is usually due to 'struct A1' being packed, which can lead to unaligned accesses}}
+};
+
+struct A2 {
+ char a;
+ struct T1 b;
+};
+
+struct __attribute__((packed)) A3 {
+ char a;
+ struct T1 b __attribute__((aligned(4)));
+};
+
+#pragma pack(push, 1)
+struct A4 {
+ char a;
+ struct T1 b; // expected-warning {{field b within 'struct A4' is less aligned than 'struct T1' and is usually due to 'struct A4' being packed, which can lead to unaligned accesses}}
+};
+
+struct A5 {
+ char a;
+ struct T1 b __attribute__((aligned(4))); // expected-warning {{field b within 'struct A5' is less aligned than 'struct T1' and is usually due to 'struct A5' being packed, which can lead to unaligned accesses}}
+};
+#pragma pack(pop)
+
+struct __attribute__((packed)) A6 {
+ struct T1 a;
+};
+
+struct A7 {
+ char a;
+ struct T1 b __attribute__((packed));
+};
+
+struct A8 {
+ char a;
+ char b;
+ short c;
+ struct T1 d;
+};
+
+struct A9 {
+ char a;
+ struct T2 b;
+};
+
+struct A10 {
+ char a;
+ struct T2 b __attribute__((aligned(4)));
+};
+
+struct __attribute__((packed)) A11 {
+ char a;
+ struct T2 b;
+};
+
+struct __attribute__((packed)) U40 {
+ char a;
+ struct A1 b;
+ int c;
+};
+
+struct __attribute__((packed)) U41 {
+ char a;
+ struct A3 b; // expected-warning {{field b within 'struct U41' is less aligned than 'struct A3' and is usually due to 'struct U41' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+#pragma pack(push, 1)
+struct U42 {
+ char a;
+ struct A1 b;
+ int c;
+};
+#pragma pack(pop)
+
+struct __attribute__((packed)) U43 {
+ char a;
+ struct A9 b;
+ int c;
+};
+
+struct __attribute__((packed)) U44 {
+ char a;
+ struct A10 b; // expected-warning {{field b within 'struct U44' is less aligned than 'struct A10' and is usually due to 'struct U44' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+#pragma pack(push, 1)
+
+struct U45 {
+ char a;
+ struct A10 b; // expected-warning {{field b within 'struct U45' is less aligned than 'struct A10' and is usually due to 'struct U45' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+#pragma pack(pop)
+
+struct __attribute__((packed)) U46 {
+ char a;
+ struct A2 b; // expected-warning {{field b within 'struct U46' is less aligned than 'struct A2' and is usually due to 'struct U46' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((packed)) U47 {
+ char a;
+ struct A8 b; // expected-warning {{field b within 'struct U47' is less aligned than 'struct A8' and is usually due to 'struct U47' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+#pragma pack(push, 1)
+struct U48 {
+ char a;
+ struct A8 b; // expected-warning {{field b within 'struct U48' is less aligned than 'struct A8' and is usually due to 'struct U48' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+#pragma pack(pop)
+
+struct U49 {
+ char a;
+ struct A11 b;
+ int c;
+};
+
+struct U50 {
+ char a;
+ struct A1 b;
+ int c;
+};
+
+struct U51 {
+ char a;
+ struct A5 b;
+ int c;
+};
+
+struct __attribute__((packed)) U52 {
+ char a;
+ struct A6 b;
+};
+
+struct U53 {
+ char a;
+ struct A4 b;
+};
+
+struct U54 {
+ char b;
+ struct A7 c;
+};
+
+struct U1 s1;
+struct U2 s2;
+struct U3 s3;
+struct U4 s4;
+struct U5 s5;
+struct U6 s6;
+struct U7 s7;
+struct U8 s8;
+struct U9 s9;
+struct U10 s10;
+struct U11 s11;
+struct U12 s12;
+struct U13 s13;
+struct U14 s14;
+struct U15 s15;
+struct U16 s16;
+struct U17 s17;
+struct U18 s18;
+struct U19 s19;
+struct U20 s20;
+struct U21 s21;
+struct U22 s22;
+struct U23 s23;
+struct U24 s24;
+struct U25 s25;
+struct U26 s26;
+struct U27 s27;
+struct U28 s28;
+struct U29 s29;
+struct U30 s30;
+struct U31 s31;
+struct U32 s32;
+struct U33 s33;
+struct U34 s34;
+struct U35 s35;
+struct U36 s36;
+struct U37 s37;
+struct U38 s38;
+struct U39 s39;
+struct U40 s40;
+struct U41 s41;
+struct U42 s42;
+struct U43 s43;
+struct U44 s44;
+struct U45 s45;
+struct U46 s46;
+struct U47 s47;
+struct U48 s48;
+struct U49 s49;
+struct U50 s50;
+struct U51 s51;
+struct U52 s52;
+struct U53 s53;
+struct U54 s54;
diff --git a/clang/test/Sema/test-wunaligned-access.cpp b/clang/test/Sema/test-wunaligned-access.cpp
new file mode 100644
index 0000000000000..33f518310b0b1
--- /dev/null
+++ b/clang/test/Sema/test-wunaligned-access.cpp
@@ -0,0 +1,274 @@
+// RUN: %clang_cc1 %s -triple=armv7-none-none-eabi -verify -Wunaligned-access -S -emit-llvm -o %t
+// REQUIRES: arm-registered-target
+//
+// This test suite tests the warning triggered by the -Wunaligned-access option.
+// The warning occurs when a struct or other type of record contains a field
+// that is itself a record. The outer record must be a packed structure, while
+// while the inner record must be unpacked. This is the fundamental condition
+// for the warning to be triggered. Some of these tests may have three layers.
+//
+// The command line option -fsyntax-only is not used as Clang needs to be
+// forced to layout the structs used in this test.
+// The triple in the command line above is used for the assumptions about
+// size and alignment of types.
+
+// Packed-Unpacked Tests (No Pragma)
+
+struct T1 {
+ char a;
+ int b;
+};
+
+struct __attribute__((packed)) U1 {
+ char a;
+ T1 b; // expected-warning {{field b within 'U1' is less aligned than 'T1' and is usually due to 'U1' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((packed)) U2 {
+ char a;
+ T1 b __attribute__((aligned(4)));
+ int c;
+};
+
+struct __attribute__((packed)) U3 {
+ char a;
+ char b;
+ short c;
+ T1 d;
+};
+
+struct __attribute__((packed)) U4 {
+ T1 a;
+ int b;
+};
+
+struct __attribute__((aligned(4), packed)) U5 {
+ char a;
+ T1 b; // expected-warning {{field b within 'U5' is less aligned than 'T1' and is usually due to 'U5' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((aligned(4), packed)) U6 {
+ char a;
+ char b;
+ short c;
+ T1 d;
+};
+
+// Packed-Unpacked Tests with Pragma
+
+#pragma pack(push, 1)
+
+struct __attribute__((packed)) U7 {
+ char a;
+ T1 b; // expected-warning {{field b within 'U7' is less aligned than 'T1' and is usually due to 'U7' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((packed)) U8 {
+ char a;
+ T1 b __attribute__((aligned(4))); // expected-warning {{field b within 'U8' is less aligned than 'T1' and is usually due to 'U8' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct __attribute__((aligned(4))) U9 {
+ char a;
+ T1 b; // expected-warning {{field b within 'U9' is less aligned than 'T1' and is usually due to 'U9' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct U10 {
+ char a;
+ T1 b; // expected-warning {{field b within 'U10' is less aligned than 'T1' and is usually due to 'U10' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+#pragma pack(pop)
+
+// Packed-Packed Tests
+
+struct __attribute__((packed)) T2 {
+ char a;
+ int b;
+};
+
+struct __attribute__((packed)) U11 {
+ char a;
+ T2 b;
+ int c;
+};
+
+#pragma pack(push, 1)
+struct U12 {
+ char a;
+ T2 b;
+ int c;
+};
+#pragma pack(pop)
+
+// Unpacked-Packed Tests
+
+struct U13 {
+ char a;
+ T2 b;
+ int c;
+};
+
+struct U14 {
+ char a;
+ T2 b __attribute__((aligned(4)));
+ int c;
+};
+
+// Unpacked-Unpacked Test
+
+struct T3 {
+ char a;
+ int b;
+};
+
+struct U15 {
+ char a;
+ T3 b;
+ int c;
+};
+
+// Packed-Packed-Unpacked Test (No pragma)
+
+struct __attribute__((packed)) A1 {
+ char a;
+ T1 b; // expected-warning {{field b within 'A1' is less aligned than 'T1' and is usually due to 'A1' being packed, which can lead to unaligned accesses}}
+};
+
+struct __attribute__((packed)) U16 {
+ char a;
+ A1 b;
+ int c;
+};
+
+struct __attribute__((packed)) A2 {
+ char a;
+ T1 b __attribute__((aligned(4)));
+};
+
+struct __attribute__((packed)) U17 {
+ char a;
+ A2 b; // expected-warning {{field b within 'U17' is less aligned than 'A2' and is usually due to 'U17' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+// Packed-Unpacked-Packed tests
+
+struct A3 {
+ char a;
+ T2 b;
+};
+
+struct __attribute__((packed)) U18 {
+ char a;
+ A3 b;
+ int c;
+};
+
+struct A4 {
+ char a;
+ T2 b;
+ int c;
+};
+
+#pragma pack(push, 1)
+struct U19 {
+ char a;
+ A4 b; // expected-warning {{field b within 'U19' is less aligned than 'A4' and is usually due to 'U19' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+#pragma pack(pop)
+
+// Packed-Unpacked-Unpacked tests
+
+struct A5 {
+ char a;
+ T1 b;
+};
+
+struct __attribute__((packed)) U20 {
+ char a;
+ A5 b; // expected-warning {{field b within 'U20' is less aligned than 'A5' and is usually due to 'U20' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+
+struct A6 {
+ char a;
+ T1 b;
+};
+
+#pragma pack(push, 1)
+struct U21 {
+ char a;
+ A6 b; // expected-warning {{field b within 'U21' is less aligned than 'A6' and is usually due to 'U21' being packed, which can lead to unaligned accesses}}
+ int c;
+};
+#pragma pack(pop)
+
+// Unpacked-Packed-Packed test
+
+struct __attribute__((packed)) A7 {
+ char a;
+ T2 b;
+};
+
+struct U22 {
+ char a;
+ A7 b;
+ int c;
+};
+
+// Unpacked-Packed-Unpacked tests
+
+struct __attribute__((packed)) A8 {
+ char a;
+ T1 b; // expected-warning {{field b within 'A8' is less aligned than 'T1' and is usually due to 'A8' being packed, which can lead to unaligned accesses}}
+};
+
+struct U23 {
+ char a;
+ A8 b;
+ int c;
+};
+
+struct __attribute__((packed)) A9 {
+ char a;
+ T1 b __attribute__((aligned(4)));
+};
+
+struct U24 {
+ char a;
+ A9 b;
+ int c;
+};
+
+struct U1 s1;
+struct U2 s2;
+struct U3 s3;
+struct U4 s4;
+struct U5 s5;
+struct U6 s6;
+struct U7 s7;
+struct U8 s8;
+struct U9 s9;
+struct U10 s10;
+struct U11 s11;
+struct U12 s12;
+struct U13 s13;
+struct U14 s14;
+struct U15 s15;
+struct U16 s16;
+struct U17 s17;
+struct U18 s18;
+struct U19 s19;
+struct U20 s20;
+struct U21 s21;
+struct U22 s22;
+struct U23 s23;
+struct U24 s24;
\ No newline at end of file
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