Added support for "#pragma clang section relro=<name>"

Differential Revision: https://reviews.llvm.org/D68806

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@374934 91177308-0d34-0410-b5e6-96231b3b80d8

docs/LanguageExtensions.rst

@@ -3445,14 +3445,14 @@ The section names can be specified as:
 
 .. code-block:: c++
 
-  #pragma clang section bss="myBSS" data="myData" rodata="myRodata" text="myText"
+  #pragma clang section bss="myBSS" data="myData" rodata="myRodata" relro="myRelro" text="myText"
 
 The section names can be reverted back to default name by supplying an empty
 string to the section kind, for example:
 
 .. code-block:: c++
 
-  #pragma clang section bss="" data="" text="" rodata=""
+  #pragma clang section bss="" data="" text="" rodata="" relro=""
 
 The ``#pragma clang section`` directive obeys the following rules:
 

include/clang/Basic/Attr.td

@@ -2020,6 +2020,14 @@ def PragmaClangRodataSection : InheritableAttr {
   let Documentation = [Undocumented];
 }
 
+def PragmaClangRelroSection : InheritableAttr {
+  // This attribute has no spellings as it is only ever created implicitly.
+  let Spellings = [];
+  let Args = [StringArgument<"Name">];
+  let Subjects = SubjectList<[GlobalVar], ErrorDiag>;
+  let Documentation = [Undocumented];
+}
+
 def PragmaClangTextSection : InheritableAttr {
   // This attribute has no spellings as it is only ever created implicitly.
   let Spellings = [];

include/clang/Basic/DiagnosticParseKinds.td

@@ -976,9 +976,9 @@ def err_pragma_misplaced_in_decl : Error<"this pragma cannot appear in %0 declar
 
 // '#pragma clang section' related errors
 def err_pragma_expected_clang_section_name : Error<
-  "expected one of [bss|data|rodata|text] section kind in '#pragma %0'">;
+  "expected one of [bss|data|rodata|text|relro] section kind in '#pragma %0'">;
 def err_pragma_clang_section_expected_equal : Error<
-  "expected '=' following '#pragma clang section %select{invalid|bss|data|rodata|text}0'">;
+  "expected '=' following '#pragma clang section %select{invalid|bss|data|rodata|text|relro}0'">;
 def warn_pragma_expected_section_name : Warning<
   "expected a string literal for the section name in '#pragma %0' - ignored">,
   InGroup<IgnoredPragmas>;

include/clang/Sema/Sema.h

@@ -418,7 +418,8 @@ public:
     PCSK_BSS          = 1,
     PCSK_Data         = 2,
     PCSK_Rodata       = 3,
-    PCSK_Text         = 4
+    PCSK_Text         = 4,
+    PCSK_Relro        = 5
    };
 
   enum PragmaClangSectionAction {
@@ -439,6 +440,7 @@ public:
    PragmaClangSection PragmaClangBSSSection;
    PragmaClangSection PragmaClangDataSection;
    PragmaClangSection PragmaClangRodataSection;
+   PragmaClangSection PragmaClangRelroSection;
    PragmaClangSection PragmaClangTextSection;
 
   enum PragmaMsStackAction {

lib/CodeGen/CGDecl.cpp

@@ -419,6 +419,8 @@ void CodeGenFunction::EmitStaticVarDecl(const VarDecl &D,
     var->addAttribute("data-section", SA->getName());
   if (auto *SA = D.getAttr<PragmaClangRodataSectionAttr>())
     var->addAttribute("rodata-section", SA->getName());
+  if (auto *SA = D.getAttr<PragmaClangRelroSectionAttr>())
+    var->addAttribute("relro-section", SA->getName());
 
   if (const SectionAttr *SA = D.getAttr<SectionAttr>())
     var->setSection(SA->getName());

lib/CodeGen/CodeGenModule.cpp

@@ -1717,6 +1717,8 @@ void CodeGenModule::setNonAliasAttributes(GlobalDecl GD,
         GV->addAttribute("data-section", SA->getName());
       if (auto *SA = D->getAttr<PragmaClangRodataSectionAttr>())
         GV->addAttribute("rodata-section", SA->getName());
+      if (auto *SA = D->getAttr<PragmaClangRelroSectionAttr>())
+        GV->addAttribute("relro-section", SA->getName());
     }
 
     if (auto *F = dyn_cast<llvm::Function>(GO)) {
@@ -4118,6 +4120,7 @@ static bool isVarDeclStrongDefinition(const ASTContext &Context,
   // If no specialized section name is applicable, it will resort to default.
   if (D->hasAttr<PragmaClangBSSSectionAttr>() ||
       D->hasAttr<PragmaClangDataSectionAttr>() ||
+      D->hasAttr<PragmaClangRelroSectionAttr>() ||
       D->hasAttr<PragmaClangRodataSectionAttr>())
     return true;
 

lib/Parse/ParsePragma.cpp

@@ -1790,7 +1790,7 @@ void PragmaMSStructHandler::HandlePragma(Preprocessor &PP,
                       /*IsReinject=*/false);
 }
 
-// #pragma clang section bss="abc" data="" rodata="def" text=""
+// #pragma clang section bss="abc" data="" rodata="def" text="" relro=""
 void PragmaClangSectionHandler::HandlePragma(Preprocessor &PP,
                                              PragmaIntroducer Introducer,
                                              Token &FirstToken) {
@@ -1812,6 +1812,8 @@ void PragmaClangSectionHandler::HandlePragma(Preprocessor &PP,
       SecKind = Sema::PragmaClangSectionKind::PCSK_Data;
     else if (SecType->isStr("rodata"))
       SecKind = Sema::PragmaClangSectionKind::PCSK_Rodata;
+    else if (SecType->isStr("relro"))
+      SecKind = Sema::PragmaClangSectionKind::PCSK_Relro;
     else if (SecType->isStr("text"))
       SecKind = Sema::PragmaClangSectionKind::PCSK_Text;
     else {

lib/Sema/SemaAttr.cpp

@@ -266,6 +266,9 @@ void Sema::ActOnPragmaClangSection(SourceLocation PragmaLoc, PragmaClangSectionA
     case PragmaClangSectionKind::PCSK_Rodata:
       CSec = &PragmaClangRodataSection;
       break;
+    case PragmaClangSectionKind::PCSK_Relro:
+      CSec = &PragmaClangRelroSection;
+      break;
     case PragmaClangSectionKind::PCSK_Text:
       CSec = &PragmaClangTextSection;
       break;

lib/Sema/SemaDecl.cpp

@@ -12657,6 +12657,11 @@ void Sema::FinalizeDeclaration(Decl *ThisDecl) {
           Context, PragmaClangRodataSection.SectionName,
           PragmaClangRodataSection.PragmaLocation,
           AttributeCommonInfo::AS_Pragma));
+    if (PragmaClangRelroSection.Valid)
+      VD->addAttr(PragmaClangRelroSectionAttr::CreateImplicit(
+          Context, PragmaClangRelroSection.SectionName,
+          PragmaClangRelroSection.PragmaLocation,
+          AttributeCommonInfo::AS_Pragma));
   }
 
   if (auto *DD = dyn_cast<DecompositionDecl>(ThisDecl)) {

test/CodeGenCXX/clang-sections.cpp

@@ -29,17 +29,20 @@ int goo(void) {  // my_text.2
   static int lstat_h;  // my_bss.2
   return zoo(g, &lstat_h);
 }
-#pragma clang section rodata="my_rodata.2" data="my_data.2"
+#pragma clang section rodata="my_rodata.2" data="my_data.2" relro="my_relro.2"
 int l = 5; // my_data.2
 extern const int m;
 const int m = 6; // my_rodata.2
+
+typedef int (*fptr_t)(void);
+const fptr_t fptrs[2] = {&foo, &goo};
 #pragma clang section rodata="" data="" bss="" text=""
 int n; // default
 int o = 6; // default
 extern const int p;
 const int p = 7; // default
 int hoo(void) {
-  return b;
+  return b + fptrs[f]();
 }
 }
 //CHECK: @a = global i32 0, align 4 #0
@@ -62,17 +65,19 @@ int hoo(void) {
 //CHECK: @n = global i32 0, align 4
 //CHECK: @o = global i32 6, align 4
 //CHECK: @p = constant i32 7, align 4
+//CHECK: @_ZL5fptrs = internal constant [2 x i32 ()*] [i32 ()* @foo, i32 ()* @goo], align 4 #3
 
-//CHECK: define i32 @foo() #4 {
-//CHECK: define i32 @goo() #5 {
-//CHECK: declare i32 @zoo(i32*, i32*) #6
-//CHECK: define i32 @hoo() #7 {
+//CHECK: define i32 @foo() #5 {
+//CHECK: define i32 @goo() #6 {
+//CHECK: declare i32 @zoo(i32*, i32*) #7
+//CHECK: define i32 @hoo() #8 {
 
 //CHECK: attributes #0 = { "bss-section"="my_bss.1" "data-section"="my_data.1" "rodata-section"="my_rodata.1" }
 //CHECK: attributes #1 = { "data-section"="my_data.1" "rodata-section"="my_rodata.1" }
 //CHECK: attributes #2 = { "bss-section"="my_bss.2" "rodata-section"="my_rodata.1" }
-//CHECK: attributes #3 = { "bss-section"="my_bss.2" "data-section"="my_data.2" "rodata-section"="my_rodata.2" }
-//CHECK: attributes #4 = { {{.*"implicit-section-name"="my_text.1".*}} }
-//CHECK: attributes #5 = { {{.*"implicit-section-name"="my_text.2".*}} }
-//CHECK-NOT: attributes #6 = { {{.*"implicit-section-name".*}} }
+//CHECK: attributes #3 = { "bss-section"="my_bss.2" "data-section"="my_data.2" "relro-section"="my_relro.2" "rodata-section"="my_rodata.2" }
+//CHECK: attributes #4 = { "relro-section"="my_relro.2" }
+//CHECK: attributes #5 = { {{.*"implicit-section-name"="my_text.1".*}} }
+//CHECK: attributes #6 = { {{.*"implicit-section-name"="my_text.2".*}} }
 //CHECK-NOT: attributes #7 = { {{.*"implicit-section-name".*}} }
+//CHECK-NOT: attributes #8 = { {{.*"implicit-section-name".*}} }

test/Sema/pragma-clang-section.c

@@ -3,15 +3,17 @@
 #pragma clang section bss="" data="" rodata="" text=""
 #pragma clang section
 
-#pragma clang section dss="mybss.2" // expected-error {{expected one of [bss|data|rodata|text] section kind in '#pragma clang section'}}
-#pragma clang section deta="mydata.2" // expected-error {{expected one of [bss|data|rodata|text] section kind in '#pragma clang section'}}
-#pragma clang section rodeta="rodata.2" // expected-error {{expected one of [bss|data|rodata|text] section kind in '#pragma clang section'}}
-#pragma clang section taxt="text.2" // expected-error {{expected one of [bss|data|rodata|text] section kind in '#pragma clang section'}}
+#pragma clang section dss="mybss.2" // expected-error {{expected one of [bss|data|rodata|text|relro] section kind in '#pragma clang section'}}
+#pragma clang section deta="mydata.2" // expected-error {{expected one of [bss|data|rodata|text|relro] section kind in '#pragma clang section'}}
+#pragma clang section rodeta="rodata.2" // expected-error {{expected one of [bss|data|rodata|text|relro] section kind in '#pragma clang section'}}
+#pragma clang section taxt="text.2" // expected-error {{expected one of [bss|data|rodata|text|relro] section kind in '#pragma clang section'}}
 
-#pragma clang section section bss="mybss.2"  // expected-error {{expected one of [bss|data|rodata|text] section kind in '#pragma clang section'}}
+#pragma clang section section bss="mybss.2"  // expected-error {{expected one of [bss|data|rodata|text|relro] section kind in '#pragma clang section'}}
 
 #pragma clang section bss "mybss.2"   // expected-error {{expected '=' following '#pragma clang section bss'}}
 #pragma clang section data "mydata.2"   // expected-error {{expected '=' following '#pragma clang section data'}}
 #pragma clang section rodata "myrodata.2"   // expected-error {{expected '=' following '#pragma clang section rodata'}}
-#pragma clang section bss="" data="" rodata="" text="" more //expected-error {{expected one of [bss|data|rodata|text] section kind in '#pragma clang section'}}
+#pragma clang section text "text.2"   // expected-error {{expected '=' following '#pragma clang section text'}}
+#pragma clang section relro "relro.2"   // expected-error {{expected '=' following '#pragma clang section relro'}}
+#pragma clang section bss="" data="" rodata="" text="" more //expected-error {{expected one of [bss|data|rodata|text|relro] section kind in '#pragma clang section'}}
 int a;