From 2c87d24da09ecd2c14c38a0b4f7a0e3f332b08ee Mon Sep 17 00:00:00 2001 From: Evgeniy Stepanov Date: Thu, 8 Oct 2015 21:35:26 +0000 Subject: [PATCH] New MSan mapping layout (llvm part). This is an implementation of https://github.com/google/sanitizers/issues/579 It has a number of advantages over the current mapping: * Works for non-PIE executables. * Does not require ASLR; as a consequence, debugging MSan programs in gdb no longer requires "set disable-randomization off". * Supports linux kernels >=4.1.2. * The code is marginally faster and smaller. This is an ABI break. We never really promised ABI stability, but this patch includes a courtesy escape hatch: a compile-time macro that reverts back to the old mapping layout. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249753 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Instrumentation/MemorySanitizer.cpp | 22 +++++++++++++++------- .../MemorySanitizer/origin-alignment.ll | 10 ++++++---- 2 files changed, 21 insertions(+), 11 deletions(-) diff --git a/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/lib/Transforms/Instrumentation/MemorySanitizer.cpp index 9d4c7de..bc6da5a 100644 --- a/lib/Transforms/Instrumentation/MemorySanitizer.cpp +++ b/lib/Transforms/Instrumentation/MemorySanitizer.cpp @@ -232,10 +232,17 @@ static const MemoryMapParams Linux_I386_MemoryMapParams = { // x86_64 Linux static const MemoryMapParams Linux_X86_64_MemoryMapParams = { +#ifdef MSAN_LINUX_X86_64_OLD_MAPPING 0x400000000000, // AndMask 0, // XorMask (not used) 0, // ShadowBase (not used) 0x200000000000, // OriginBase +#else + 0, // AndMask (not used) + 0x500000000000, // XorMask + 0, // ShadowBase (not used) + 0x100000000000, // OriginBase +#endif }; // mips64 Linux @@ -926,16 +933,17 @@ struct MemorySanitizerVisitor : public InstVisitor { /// /// Offset = (Addr & ~AndMask) ^ XorMask Value *getShadowPtrOffset(Value *Addr, IRBuilder<> &IRB) { + Value *OffsetLong = IRB.CreatePointerCast(Addr, MS.IntptrTy); + uint64_t AndMask = MS.MapParams->AndMask; - assert(AndMask != 0 && "AndMask shall be specified"); - Value *OffsetLong = - IRB.CreateAnd(IRB.CreatePointerCast(Addr, MS.IntptrTy), - ConstantInt::get(MS.IntptrTy, ~AndMask)); + if (AndMask) + OffsetLong = + IRB.CreateAnd(OffsetLong, ConstantInt::get(MS.IntptrTy, ~AndMask)); uint64_t XorMask = MS.MapParams->XorMask; - if (XorMask != 0) - OffsetLong = IRB.CreateXor(OffsetLong, - ConstantInt::get(MS.IntptrTy, XorMask)); + if (XorMask) + OffsetLong = + IRB.CreateXor(OffsetLong, ConstantInt::get(MS.IntptrTy, XorMask)); return OffsetLong; } diff --git a/test/Instrumentation/MemorySanitizer/origin-alignment.ll b/test/Instrumentation/MemorySanitizer/origin-alignment.ll index ce0dbfc..562d194 100644 --- a/test/Instrumentation/MemorySanitizer/origin-alignment.ll +++ b/test/Instrumentation/MemorySanitizer/origin-alignment.ll @@ -24,7 +24,7 @@ entry: ; CHECK-ORIGINS1: [[ORIGIN:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls ; CHECK-ORIGINS2: [[ORIGIN0:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls ; CHECK-ORIGINS2: [[ORIGIN:%[01-9a-z]+]] = call i32 @__msan_chain_origin(i32 [[ORIGIN0]]) -; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 add (i64 and (i64 ptrtoint {{.*}} to i32*), align 8 +; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 add (i64 xor (i64 ptrtoint (i8* @a8 to i64), i64 {{.*}}), i64 {{.*}}) to i32*), align 8 ; CHECK: ret void @@ -39,7 +39,7 @@ entry: ; CHECK-ORIGINS1: [[ORIGIN:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls ; CHECK-ORIGINS2: [[ORIGIN0:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls ; CHECK-ORIGINS2: [[ORIGIN:%[01-9a-z]+]] = call i32 @__msan_chain_origin(i32 [[ORIGIN0]]) -; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 add (i64 and (i64 ptrtoint {{.*}} to i32*), align 4 +; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 add (i64 xor (i64 ptrtoint (i8* @a4 to i64), i64 {{.*}}), i64 {{.*}}) to i32*), align 4 ; CHECK: ret void @@ -54,7 +54,8 @@ entry: ; CHECK-ORIGINS1: [[ORIGIN:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls ; CHECK-ORIGINS2: [[ORIGIN0:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls ; CHECK-ORIGINS2: [[ORIGIN:%[01-9a-z]+]] = call i32 @__msan_chain_origin(i32 [[ORIGIN0]]) -; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 and (i64 add (i64 and (i64 ptrtoint {{.*}} i64 -4) to i32*), align 4 +; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 and (i64 add (i64 xor (i64 ptrtoint (i8* @a2 to i64), i64 {{.*}}), i64 {{.*}}), i64 -4) to i32*), align 4 + ; CHECK: ret void @@ -69,5 +70,6 @@ entry: ; CHECK-ORIGINS1: [[ORIGIN:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls ; CHECK-ORIGINS2: [[ORIGIN0:%[01-9a-z]+]] = load {{.*}} @__msan_param_origin_tls ; CHECK-ORIGINS2: [[ORIGIN:%[01-9a-z]+]] = call i32 @__msan_chain_origin(i32 [[ORIGIN0]]) -; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 and (i64 add (i64 and (i64 ptrtoint {{.*}} i64 -4) to i32*), align 4 +; CHECK: store i32 [[ORIGIN]], i32* inttoptr (i64 and (i64 add (i64 xor (i64 ptrtoint (i8* @a1 to i64), i64 {{.*}}), i64 {{.*}}), i64 -4) to i32*), align 4 + ; CHECK: ret void -- 2.6.1