From 9c7dd8ca502a6397839f7462609f19897855830d Mon Sep 17 00:00:00 2001
From: Dmitry Mikulin <dmitry.mikulin@sony.com>
Date: Tue, 15 Oct 2019 18:31:10 +0000
Subject: [PATCH] Added support for "#pragma clang section relro=<name>"

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@374934 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/IR/GlobalVariable.h             |  1 +
 lib/CodeGen/TargetLoweringObjectFileImpl.cpp |  2 +
 lib/Target/TargetLoweringObjectFile.cpp      |  1 +
 test/MC/ELF/section-relro.ll                 | 65 ++++++++++++++++++++
 4 files changed, 69 insertions(+)
 create mode 100644 test/MC/ELF/section-relro.ll

diff --git a/include/llvm/IR/GlobalVariable.h b/include/llvm/IR/GlobalVariable.h
index 2e2c8c47791..2c730bc312e 100644
--- a/include/llvm/IR/GlobalVariable.h
+++ b/include/llvm/IR/GlobalVariable.h
@@ -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");
   }
 
diff --git a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
index 89a98bba65e..4978f4b9500 100644
--- a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
+++ b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp
@@ -568,6 +568,8 @@ MCSection *TargetLoweringObjectFileELF::getExplicitSectionGlobal(
       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();
     }
diff --git a/lib/Target/TargetLoweringObjectFile.cpp b/lib/Target/TargetLoweringObjectFile.cpp
index 17274e1c2c6..dcd3934de0f 100644
--- a/lib/Target/TargetLoweringObjectFile.cpp
+++ b/lib/Target/TargetLoweringObjectFile.cpp
@@ -253,6 +253,7 @@ MCSection *TargetLoweringObjectFile::SectionForGlobal(
     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);
     }
diff --git a/test/MC/ELF/section-relro.ll b/test/MC/ELF/section-relro.ll
new file mode 100644
index 00000000000..27fc109dea5
--- /dev/null
+++ b/test/MC/ELF/section-relro.ll
@@ -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"
+
+@funcs_relro = hidden constant [2 x i32 ()*] [i32 ()* bitcast (i32 (...)* @func1 to i32 ()*), i32 ()* bitcast (i32 (...)* @func2 to i32 ()*)], align 16 #0
+@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:  }
-- 
2.40.0