[asan] Prevent folding of globals with redzones

Summary:
ICF prevented by removing unnamed_addr and local_unnamed_addr for all sanitized
globals.
Also in general unnamed_addr is not valid here as address now is important for
ODR violation detector and redzone poisoning.

Before the patch ICF on globals caused:
1. false ODR reports when we register global on the same address more than once
2. globals buffer overflow if we fold variables of smaller type inside of large
type. Then the smaller one will poison redzone which overlaps with the larger one.

Reviewers: eugenis, pcc

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D55857

llvm-svn: 349706

6 files changed, 14 insertions, 10 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 2ede46774b2..0c7aec4ac69 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -2150,6 +2150,10 @@ bool AddressSanitizerModule::InstrumentGlobals(IRBuilder<> &IRB, Module &M, bool
     NewGlobal->copyAttributesFrom(G);
     NewGlobal->setComdat(G->getComdat());
     NewGlobal->setAlignment(MinRZ);
+    // Don't fold globals with redzones. ODR violation detector and redzone
+    // poisoning implicitly creates a dependence on the global's address, so it
+    // is no longer valid for it to be marked unnamed_addr.
+    NewGlobal->setUnnamedAddr(GlobalValue::UnnamedAddr::None);
 
     // Move null-terminated C strings to "__asan_cstring" section on Darwin.
     if (TargetTriple.isOSBinFormatMachO() && !G->hasSection() &&
diff --git a/llvm/test/Instrumentation/AddressSanitizer/global_cstring_darwin.ll b/llvm/test/Instrumentation/AddressSanitizer/global_cstring_darwin.ll
index eb31c15b344..0fc3205ba49 100644
--- a/llvm/test/Instrumentation/AddressSanitizer/global_cstring_darwin.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/global_cstring_darwin.ll
@@ -8,14 +8,14 @@ target triple = "x86_64-apple-macosx10.10.0"
 @.str.1 = private unnamed_addr constant [13 x i8] c"Hello world.\00", align 1
 @.str.2 = private unnamed_addr constant [4 x i8] c"%s\0A\00", align 1
 
-; CHECK: @.str.1 = internal unnamed_addr constant { [13 x i8], [51 x i8] } { [13 x i8] c"Hello world.\00", [51 x i8] zeroinitializer }, section "__TEXT,__asan_cstring,regular", align 32
-; CHECK: @.str.2 = internal unnamed_addr constant { [4 x i8], [60 x i8] } { [4 x i8] c"%s\0A\00", [60 x i8] zeroinitializer }, section "__TEXT,__asan_cstring,regular", align 32
+; CHECK: @.str.1 = internal constant { [13 x i8], [51 x i8] } { [13 x i8] c"Hello world.\00", [51 x i8] zeroinitializer }, section "__TEXT,__asan_cstring,regular", align 32
+; CHECK: @.str.2 = internal constant { [4 x i8], [60 x i8] } { [4 x i8] c"%s\0A\00", [60 x i8] zeroinitializer }, section "__TEXT,__asan_cstring,regular", align 32
 
 ; Shouldn't be put into special section:
 @.str.3 = private unnamed_addr constant [4 x i8] c"\00\01\02\03", align 1
 @.str.4 = private unnamed_addr global [7 x i8] c"Hello.\00", align 1
 @.str.5 = private unnamed_addr constant [8 x i8] c"Hello.\00\00", align 1
 
-; CHECK: @.str.3 = internal unnamed_addr constant { [4 x i8], [60 x i8] } { [4 x i8] c"\00\01\02\03", [60 x i8] zeroinitializer }, align 32
-; CHECK: @.str.4 = private unnamed_addr global { [7 x i8], [57 x i8] } { [7 x i8] c"Hello.\00", [57 x i8] zeroinitializer }, align 32
-; CHECK: @.str.5 = internal unnamed_addr constant { [8 x i8], [56 x i8] } { [8 x i8] c"Hello.\00\00", [56 x i8] zeroinitializer }, align 32
+; CHECK: @.str.3 = internal constant { [4 x i8], [60 x i8] } { [4 x i8] c"\00\01\02\03", [60 x i8] zeroinitializer }, align 32
+; CHECK: @.str.4 = private global { [7 x i8], [57 x i8] } { [7 x i8] c"Hello.\00", [57 x i8] zeroinitializer }, align 32
+; CHECK: @.str.5 = internal constant { [8 x i8], [56 x i8] } { [8 x i8] c"Hello.\00\00", [56 x i8] zeroinitializer }, align 32
diff --git a/llvm/test/Instrumentation/AddressSanitizer/global_metadata.ll b/llvm/test/Instrumentation/AddressSanitizer/global_metadata.ll
index ee42f1cef97..ecee7720966 100644
--- a/llvm/test/Instrumentation/AddressSanitizer/global_metadata.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/global_metadata.ll
@@ -15,7 +15,7 @@ target triple = "x86_64-unknown-linux-gnu"
 ; Check that globals were instrumented:
 
 ; CHECK: @global = global { i32, [60 x i8] } zeroinitializer, comdat, align 32
-; CHECK: @.str = internal unnamed_addr constant { [14 x i8], [50 x i8] } { [14 x i8] c"Hello, world!\00", [50 x i8] zeroinitializer }, comdat($".str${{[01-9a-f]+}}"), align 32
+; CHECK: @.str = internal constant { [14 x i8], [50 x i8] } { [14 x i8] c"Hello, world!\00", [50 x i8] zeroinitializer }, comdat($".str${{[01-9a-f]+}}"), align 32
 
 ; Check emitted location descriptions:
 ; CHECK: [[VARNAME:@___asan_gen_.[0-9]+]] = private unnamed_addr constant [7 x i8] c"global\00", align 1
diff --git a/llvm/test/Instrumentation/AddressSanitizer/global_metadata_array.ll b/llvm/test/Instrumentation/AddressSanitizer/global_metadata_array.ll
index 76f73778f0f..fbe0016140b 100644
--- a/llvm/test/Instrumentation/AddressSanitizer/global_metadata_array.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/global_metadata_array.ll
@@ -15,7 +15,7 @@ target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 
 ; Check that globals were instrumented:
 ; CHECK: @global = global { i32, [60 x i8] } zeroinitializer, align 32
-; CHECK: @.str = internal unnamed_addr constant { [14 x i8], [50 x i8] } { [14 x i8] c"Hello, world!\00", [50 x i8] zeroinitializer }{{.*}}, align 32
+; CHECK: @.str = internal constant { [14 x i8], [50 x i8] } { [14 x i8] c"Hello, world!\00", [50 x i8] zeroinitializer }{{.*}}, align 32
 
 ; Check emitted location descriptions:
 ; CHECK: [[VARNAME:@___asan_gen_.[0-9]+]] = private unnamed_addr constant [7 x i8] c"global\00", align 1
diff --git a/llvm/test/Instrumentation/AddressSanitizer/global_metadata_windows.ll b/llvm/test/Instrumentation/AddressSanitizer/global_metadata_windows.ll
index eeac65e1847..5602cb26e00 100644
--- a/llvm/test/Instrumentation/AddressSanitizer/global_metadata_windows.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/global_metadata_windows.ll
@@ -14,8 +14,8 @@ $mystr = comdat any
 ; CHECK: $dead_global = comdat noduplicates
 ; CHECK: $private_str = comdat noduplicates
 
-; CHECK: @dead_global = local_unnamed_addr global { i32, [60 x i8] } { i32 42, [60 x i8] zeroinitializer }, comdat, align 32
-; CHECK: @private_str = internal unnamed_addr constant { [8 x i8], [56 x i8] } { [8 x i8] c"private\00", [56 x i8] zeroinitializer }, comdat, align 32
+; CHECK: @dead_global = global { i32, [60 x i8] } { i32 42, [60 x i8] zeroinitializer }, comdat, align 32
+; CHECK: @private_str = internal constant { [8 x i8], [56 x i8] } { [8 x i8] c"private\00", [56 x i8] zeroinitializer }, comdat, align 32
 
 ; CHECK: @__asan_global_dead_global = private global { {{.*}} }, section ".ASAN$GL", comdat($dead_global), align 64
 ; CHECK: @__asan_global_private_str = private global { {{.*}} }, section ".ASAN$GL", comdat($private_str), align 64
diff --git a/llvm/test/Instrumentation/AddressSanitizer/win-string-literal.ll b/llvm/test/Instrumentation/AddressSanitizer/win-string-literal.ll
index a86581c1e8e..05d96d123cd 100644
--- a/llvm/test/Instrumentation/AddressSanitizer/win-string-literal.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/win-string-literal.ll
@@ -7,7 +7,7 @@
 ; CHECK: $"??_C@_04JIHMPGLA@asdf?$AA@" = comdat any
 
 ; CHECK: @"??_C@_04JIHMPGLA@asdf?$AA@" =
-; CHECK-SAME: linkonce_odr dso_local unnamed_addr constant { [5 x i8], [59 x i8] }
+; CHECK-SAME: linkonce_odr dso_local constant { [5 x i8], [59 x i8] }
 ; CHECK-SAME: { [5 x i8] c"asdf\00", [59 x i8] zeroinitializer }, comdat, align 32
 
 ; CHECK: @"__asan_global_??_C@_04JIHMPGLA@asdf?$AA@" =