[dfsan] Fix getShadowAddress computation

[anoopkg6]

Fix getShadowAddress computation by adding ShadowBase if it is not zero.

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

@llvm/pr-subscribers-llvm-transforms

Author: None (anoopkg6)

Changes

Fix getShadowAddress computation by adding ShadowBase if it is not zero.

---

Full diff: https://github.com/llvm/llvm-project/pull/162864.diff

2 Files Affected:

• (modified) compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake (+1-1)
• (modified) llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp (+6-2)

diff --git a/compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake b/compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake
index ca45d7bd2af7f..05aa7e153f362 100644
--- a/compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake
+++ b/compiler-rt/cmake/Modules/AllSupportedArchDefs.cmake
@@ -36,7 +36,7 @@ set(ALL_ASAN_SUPPORTED_ARCH ${X86} ${X86_64} ${ARM32} ${ARM64} ${RISCV64}
     ${LOONGARCH64})
 set(ALL_ASAN_ABI_SUPPORTED_ARCH ${X86_64} ${ARM64} ${ARM64_32})
 set(ALL_DFSAN_SUPPORTED_ARCH ${X86_64} ${MIPS64} ${ARM64} ${LOONGARCH64})
-set(ALL_RTSAN_SUPPORTED_ARCH ${X86_64} ${ARM64})
+set(ALL_RTSAN_SUPPORTED_ARCH ${X86_64} ${ARM64}  ${S390X})
 
 if(ANDROID)
   set(OS_NAME "Android")
diff --git a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
index 5ba2167859490..cc53ec2c0f2f3 100644
--- a/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/DataFlowSanitizer.cpp
@@ -1957,8 +1957,12 @@ Value *DataFlowSanitizer::getShadowAddress(Value *Addr,
 Value *DataFlowSanitizer::getShadowAddress(Value *Addr,
                                            BasicBlock::iterator Pos) {
   IRBuilder<> IRB(Pos->getParent(), Pos);
-  Value *ShadowOffset = getShadowOffset(Addr, IRB);
-  return getShadowAddress(Addr, Pos, ShadowOffset);
+  Value *ShadowAddr = getShadowOffset(Addr, IRB);
+  uint64_t ShadowBase = MapParams->ShadowBase;
+  if (ShadowBase != 0)
+    ShadowAddr =
+        IRB.CreateAdd(ShadowAddr, ConstantInt::get(IntptrTy, ShadowBase));
+  return getShadowAddress(Addr, Pos, ShadowAddr);
 }
 
 Value *DFSanFunction::combineShadowsThenConvert(Type *T, Value *V1, Value *V2,

[thurstond]

This change would belong better in the S390X-specific pull request.

[thurstond]

(Also, it's for RTSan, not DFSan?)

[anoopkg6]

Sorry, some unrelated changes got pull into this pr. Updated push should have only one file changes.

[thurstond]

Please add "[dfsan]" to the title

[anoopkg6]

[dfsan] has been added to the tile. This pr has changes related to getShadowAddress in DFSan only. RTSAN change has been removed.
All test using memory-transfer instructions involving memcpy and memmove fail on SystemZ. e.g. origin_memcpy.c, origin_memmove.c, etc in existing dfsan tests.

[thurstond]

Thanks! Is it ready to merge?

[anoopkg6]

Yes, It is ready to merge along with #162881<#162881>. Once these two prs are merged, I will rebase SystemZ pr on top.

…

________________________________ From: Thurston Dang ***@***.***> Sent: Wednesday, October 29, 2025 3:59 PM To: llvm/llvm-project ***@***.***> Cc: Anoop Kumar ***@***.***>; Author ***@***.***> Subject: [EXTERNAL] Re: [llvm/llvm-project] [dfsan] Fix getShadowAddress computation (PR #162864) @ thurstond approved this pull request. Thanks! Is it ready to merge? — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you authored the thread. Message ID: <llvm/llvm-project/pull/162864/review/3396216461@ github. com> @thurstond approved this pull request. Thanks! Is it ready to merge? — Reply to this email directly, view it on GitHub<#162864 (review) >, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BM5K4GT3R2SS432DEH2BN4332ETCPAVCNFSM6AAAAACI3ETHUOVHI2DSMVQWIX3LMV43YUDVNRWFEZLROVSXG5CSMV3GSZLXHMZTGOJWGIYTMNBWGE >. You are receiving this because you authored the thread.Message ID: ***@***.***>

[anoopkg6]

Thanks.

…

________________________________ From: Thurston Dang ***@***.***> Sent: Wednesday, October 29, 2025 4:39 PM To: llvm/llvm-project ***@***.***> Cc: Anoop Kumar ***@***.***>; Author ***@***.***> Subject: [EXTERNAL] Re: [llvm/llvm-project] [dfsan] Fix getShadowAddress computation (PR #162864) Merged #162864 into main. — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you authored the thread. Message ID: <llvm/llvm-project/pull/162864/issue_event/20592235782@ github. com> ‍ Merged #162864<#162864 > into main. — Reply to this email directly, view it on GitHub<#162864 (comment) >, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BM5K4GS2HFDMYY4X454YTBD32EXXZAVCNFSM6AAAAACI3ETHUOVHI2DSMVQWIX3LMV45UABCJFZXG5LFIV3GK3TUJZXXI2LGNFRWC5DJN5XDWMRQGU4TEMRTGU3TQMQ >. You are receiving this because you authored the thread.Message ID: ***@***.***>