[llvm] r374934 - Added support for "#pragma clang section relro=<name>"

[Dmitry Mikulin via llvm-commits]

Author: dmikulin
Date: Tue Oct 15 11:31:10 2019
New Revision: 374934

URL: http://llvm.org/viewvc/llvm-project?rev=374934&view=rev
Log:
Added support for "#pragma clang section relro=<name>"

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

Added:
    llvm/trunk/test/MC/ELF/section-relro.ll
Modified:
    llvm/trunk/include/llvm/IR/GlobalVariable.h
    llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
    llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp

Modified: llvm/trunk/include/llvm/IR/GlobalVariable.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/GlobalVariable.h?rev=374934&r1=374933&r2=374934&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/GlobalVariable.h (original)
+++ llvm/trunk/include/llvm/IR/GlobalVariable.h Tue Oct 15 11:31:10 2019
@@ -243,6 +243,7 @@ public:
   bool hasImplicitSection() const {
     return getAttributes().hasAttribute("bss-section") ||
            getAttributes().hasAttribute("data-section") ||
+           getAttributes().hasAttribute("relro-section") ||
            getAttributes().hasAttribute("rodata-section");
   }
 

Modified: llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp?rev=374934&r1=374933&r2=374934&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp (original)
+++ llvm/trunk/lib/CodeGen/TargetLoweringObjectFileImpl.cpp Tue Oct 15 11:31:10 2019
@@ -568,6 +568,8 @@ MCSection *TargetLoweringObjectFileELF::
       SectionName = Attrs.getAttribute("bss-section").getValueAsString();
     } else if (Attrs.hasAttribute("rodata-section") && Kind.isReadOnly()) {
       SectionName = Attrs.getAttribute("rodata-section").getValueAsString();
+    } else if (Attrs.hasAttribute("relro-section") && Kind.isReadOnlyWithRel()) {
+      SectionName = Attrs.getAttribute("relro-section").getValueAsString();
     } else if (Attrs.hasAttribute("data-section") && Kind.isData()) {
       SectionName = Attrs.getAttribute("data-section").getValueAsString();
     }

Modified: llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp?rev=374934&r1=374933&r2=374934&view=diff
==============================================================================
--- llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp (original)
+++ llvm/trunk/lib/Target/TargetLoweringObjectFile.cpp Tue Oct 15 11:31:10 2019
@@ -253,6 +253,7 @@ MCSection *TargetLoweringObjectFile::Sec
     auto Attrs = GVar->getAttributes();
     if ((Attrs.hasAttribute("bss-section") && Kind.isBSS()) ||
         (Attrs.hasAttribute("data-section") && Kind.isData()) ||
+        (Attrs.hasAttribute("relro-section") && Kind.isReadOnlyWithRel()) ||
         (Attrs.hasAttribute("rodata-section") && Kind.isReadOnly()))  {
        return getExplicitSectionGlobal(GO, Kind, TM);
     }

Added: llvm/trunk/test/MC/ELF/section-relro.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/ELF/section-relro.ll?rev=374934&view=auto
==============================================================================
--- llvm/trunk/test/MC/ELF/section-relro.ll (added)
+++ llvm/trunk/test/MC/ELF/section-relro.ll Tue Oct 15 11:31:10 2019
@@ -0,0 +1,65 @@
+; Tests that data and relro are correctly placed in sections
+; specified by "#pragma clang section"
+; RUN: llc -filetype=obj -mtriple x86_64-unknown-linux %s -o - | llvm-readobj -S -t | FileCheck %s
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux"
+
+ at funcs_relro = hidden constant [2 x i32 ()*] [i32 ()* bitcast (i32 (...)* @func1 to i32 ()*), i32 ()* bitcast (i32 (...)* @func2 to i32 ()*)], align 16 #0
+ at var_data = hidden global i32 33, align 4 #0
+
+declare i32 @func1(...)
+declare i32 @func2(...)
+
+; Function Attrs: noinline nounwind optnone sspstrong uwtable
+define hidden i32 @foo(i32 %i) {
+entry:
+  %i.addr = alloca i32, align 4
+  store i32 %i, i32* %i.addr, align 4
+  %0 = load i32, i32* %i.addr, align 4
+  %idxprom = sext i32 %0 to i64
+  %arrayidx = getelementptr inbounds [2 x i32 ()*], [2 x i32 ()*]* @funcs_relro, i64 0, i64 %idxprom
+  %1 = load i32 ()*, i32 ()** %arrayidx, align 8
+  %call = call i32 %1()
+  %2 = load i32, i32* @var_data, align 4
+  %add = add nsw i32 %call, %2
+  ret i32 %add
+}
+
+attributes #0 = { "data-section"=".my_data" "relro-section"=".my_relro" "rodata-section"=".my_rodata" }
+
+; CHECK:  Section {
+; CHECK:    Index:
+; CHECK:    Name: .my_rodata
+; CHECK:    Type: SHT_PROGBITS (0x1)
+; CHECK:    Flags [ (0x2)
+; CHECK:      SHF_ALLOC (0x2)
+; CHECK:    ]
+; CHECK:    Size: 16
+; CHECK:  }
+; CHECK:  Section {
+; CHECK:    Index:
+; CHECK:    Name: .my_data
+; CHECK:    Type: SHT_PROGBITS (0x1)
+; CHECK:    Flags [ (0x3)
+; CHECK:      SHF_ALLOC (0x2)
+; CHECK:      SHF_WRITE (0x1)
+; CHECK:    ]
+; CHECK:    Size: 4
+; CHECK:  }
+; CHECK:   Symbol {
+; CHECK:    Name: funcs_relro
+; CHECK:    Value: 0x0
+; CHECK:    Size: 16
+; CHECK:    Binding: Global (0x1)
+; CHECK:    Type: Object (0x1)
+; CHECK:    Section: .my_rodata
+; CHECK:  }
+; CHECK:  Symbol {
+; CHECK:    Name: var_data
+; CHECK:    Value: 0x0
+; CHECK:    Size: 4
+; CHECK:    Binding: Global (0x1)
+; CHECK:    Type: Object (0x1)
+; CHECK:    Section: .my_data
+; CHECK:  }