[ARM][clang] Add some build attributes support

[paperchalice]

UnsafeFPMath and related flags will be removed in future, let frontend generate some hints for ARM backend to generate ABI tags.

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-codegen

Author: None (paperchalice)

Changes

UnsafeFPMath and related flags will be removed in future, let frontend generate some hints for ARM backend to generate ABI tags.

---

Full diff: https://github.com/llvm/llvm-project/pull/161106.diff

4 Files Affected:

• (modified) clang/lib/CodeGen/CodeGenModule.cpp (+27)
• (added) clang/test/CodeGen/ARM/build-attributes.c (+15)
• (modified) clang/test/CodeGen/ubsan-function-sugared.cpp (+3-3)
• (modified) clang/test/CodeGen/ubsan-function.cpp (+3-3)

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 0eac7c351b164..6baa66ed84791 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -61,6 +61,7 @@
 #include "llvm/IR/ProfileSummary.h"
 #include "llvm/ProfileData/InstrProfReader.h"
 #include "llvm/ProfileData/SampleProf.h"
+#include "llvm/Support/ARMBuildAttributes.h"
 #include "llvm/Support/CRC.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/CommandLine.h"
@@ -1383,6 +1384,32 @@ void CodeGenModule::Release() {
       }
     }
   }
+  if ((T.isARM() || T.isThumb()) && getTriple().isTargetAEABI() &&
+      getTriple().isOSBinFormatELF()) {
+    uint32_t TagVal = 0;
+    if (getCodeGenOpts().FPDenormalMode ==
+        llvm::DenormalMode::getPositiveZero())
+      TagVal = llvm::ARMBuildAttrs::PositiveZero;
+    else if (getCodeGenOpts().FPDenormalMode == llvm::DenormalMode::getIEEE())
+      TagVal = llvm::ARMBuildAttrs::IEEEDenormals;
+    else if (getCodeGenOpts().FPDenormalMode ==
+             llvm::DenormalMode::getPreserveSign())
+      TagVal = llvm::ARMBuildAttrs::PreserveFPSign;
+    getModule().addModuleFlag(llvm::Module::Warning, "arm-eabi-fp-denormal",
+                              TagVal);
+
+    if (getLangOpts().getFPExceptionMode() !=
+        LangOptions::FPExceptionModeKind::FPE_Ignore)
+      getModule().addModuleFlag(llvm::Module::Warning, "arm-eabi-fp-exceptions",
+                                llvm::ARMBuildAttrs::Allowed);
+
+    if (getLangOpts().NoHonorNaNs && getLangOpts().NoHonorInfs)
+      TagVal = llvm::ARMBuildAttrs::AllowIEEENormal;
+    else
+      TagVal = llvm::ARMBuildAttrs::AllowIEEE754;
+    getModule().addModuleFlag(llvm::Module::Warning, "arm-eabi-fp-number-model",
+                              TagVal);
+  }
 
   if (CodeGenOpts.StackClashProtector)
     getModule().addModuleFlag(
diff --git a/clang/test/CodeGen/ARM/build-attributes.c b/clang/test/CodeGen/ARM/build-attributes.c
new file mode 100644
index 0000000000000..2f7ff17df0526
--- /dev/null
+++ b/clang/test/CodeGen/ARM/build-attributes.c
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -triple arm-none-eabi -fdenormal-fp-math=positive-zero -emit-llvm -o - | FileCheck %s --check-prefix=DM-PZ
+// RUN: %clang_cc1 -triple arm-none-eabi -fdenormal-fp-math=ieee -emit-llvm -o - | FileCheck %s --check-prefix=DM-IEEE
+// RUN: %clang_cc1 -triple arm-none-eabi -fdenormal-fp-math=preserve-sign -emit-llvm -o - | FileCheck %s --check-prefix=DM-PS
+
+// RUN: %clang_cc1 -triple arm-none-eabi -menable-no-infs -menable-no-nans -emit-llvm -o - | FileCheck %s --check-prefix=NM-FIN
+// RUN: %clang_cc1 -triple arm-none-eabi -emit-llvm -o - | FileCheck %s --check-prefix=NM-IEEE
+
+// DM-PZ: !{i32 2, !"arm-eabi-fp-denormal", i32 0}
+// DM-IEEE: !{i32 2, !"arm-eabi-fp-denormal", i32 1}
+// DM-PS: !{i32 2, !"arm-eabi-fp-denormal", i32 2}
+
+// NM-FIN: !{i32 2, !"arm-eabi-fp-number-model", i32 1}
+// NM-IEEE: !{i32 2, !"arm-eabi-fp-number-model", i32 3}
+
+void foo() {}
diff --git a/clang/test/CodeGen/ubsan-function-sugared.cpp b/clang/test/CodeGen/ubsan-function-sugared.cpp
index fb2487c024ba9..2eb1e5239de50 100644
--- a/clang/test/CodeGen/ubsan-function-sugared.cpp
+++ b/clang/test/CodeGen/ubsan-function-sugared.cpp
@@ -10,9 +10,9 @@ auto fun() {}
 
 // GNU-LABEL:  define{{.*}} void @_Z6callerv()
 // MSVC-LABEL: define{{.*}} void @"?caller@@YAXXZ"()
-// ARM:   ptrtoint ptr {{.*}} to i32, !nosanitize !4
-// ARM:   and i32 {{.*}}, -2, !nosanitize !4
-// ARM:   inttoptr i32 {{.*}} to ptr, !nosanitize !4
+// ARM:   ptrtoint ptr {{.*}} to i32, !nosanitize !7
+// ARM:   and i32 {{.*}}, -2, !nosanitize !7
+// ARM:   inttoptr i32 {{.*}} to ptr, !nosanitize !7
 // CHECK: getelementptr <{ i32, i32 }>, ptr {{.*}}, i32 -1, i32 0, !nosanitize
 // CHECK: load i32, ptr {{.*}}, align {{.*}}, !nosanitize
 // CHECK: icmp eq i32 {{.*}}, -1056584962, !nosanitize
diff --git a/clang/test/CodeGen/ubsan-function.cpp b/clang/test/CodeGen/ubsan-function.cpp
index 76d4237383f83..33c110eb6a404 100644
--- a/clang/test/CodeGen/ubsan-function.cpp
+++ b/clang/test/CodeGen/ubsan-function.cpp
@@ -13,9 +13,9 @@ void fun() {}
 
 // GNU-LABEL:  define{{.*}} void @_Z6callerPFvvE(ptr noundef %f)
 // MSVC-LABEL: define{{.*}} void @"?caller@@YAXP6AXXZ@Z"(ptr noundef %f)
-// ARM:   ptrtoint ptr {{.*}} to i32, !nosanitize !5
-// ARM:   and i32 {{.*}}, -2, !nosanitize !5
-// ARM:   inttoptr i32 {{.*}} to ptr, !nosanitize !5
+// ARM:   ptrtoint ptr {{.*}} to i32, !nosanitize !8
+// ARM:   and i32 {{.*}}, -2, !nosanitize !8
+// ARM:   inttoptr i32 {{.*}} to ptr, !nosanitize !8
 // AUTH:  %[[STRIPPED:.*]] = ptrtoint ptr {{.*}} to i64, !nosanitize
 // AUTH:  call i64 @llvm.ptrauth.auth(i64 %[[STRIPPED]], i32 0, i64 0), !nosanitize
 // CHECK: getelementptr <{ i32, i32 }>, ptr {{.*}}, i32 -1, i32 0, !nosanitize