[llvm] [hwasan] Invalidate DominatorTreeAnalysis after each function is sanitized (PR #66935)

[Thurston Dang via llvm-commits]

https://github.com/thurstond created https://github.com/llvm/llvm-project/pull/66935

HWAddressSanitizerPass::run sanitizes functions one by one. The sanitization of each function - which may split blocks via insertShadowTagCheck - may result in some cached analyses are invalid. This matters because sanitizeFunction(F', FAM) may indirectly call the global stack safety analysis, hence we need to make sure the analyses of F are up to date.

Bug report: https://github.com/llvm/llvm-project/issues/66934


>From f090932f2edc6f35cec9b16c3adffe53e8c14091 Mon Sep 17 00:00:00 2001
From: Thurston Dang <thurston at google.com>
Date: Wed, 20 Sep 2023 18:11:22 +0000
Subject: [PATCH] [hwasan] Invalidate DominatorTreeAnalysis after each function
 is sanitized

HWAddressSanitizerPass::run sanitizes functions one by one. The sanitization of each function - which may split blocks via insertShadowTagCheck - may result in some cached analyses are invalid. This matters because sanitizeFunction(F', FAM) may indirectly call the global stack safety analysis, hence we need to make sure the analyses of F are up to date.

Bug report: https://github.com/llvm/llvm-project/issues/66934
---
 .../Transforms/Instrumentation/HWAddressSanitizer.cpp  | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
index 29770ece9c61eb2..1dc550ba8b54ea6 100644
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -430,8 +430,16 @@ PreservedAnalyses HWAddressSanitizerPass::run(Module &M,
 
   HWAddressSanitizer HWASan(M, Options.CompileKernel, Options.Recover, SSI);
   auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
-  for (Function &F : M)
+  for (Function &F : M) {
     HWASan.sanitizeFunction(F, FAM);
+    // After sanitizing F - which may split blocks via insertShadowTagCheck -
+    // some cached analyses are invalid. This matters because
+    // sanitizeFunction(F', FAM) may indirectly call the global stack safety
+    // analysis, hence we need to make sure the analyses of F are up to date.
+    PreservedAnalyses PA = PreservedAnalyses::all();
+    PA.abandon<DominatorTreeAnalysis>();
+    FAM.invalidate(F, PA);
+  }
 
   PreservedAnalyses PA = PreservedAnalyses::none();
   // GlobalsAA is considered stateless and does not get invalidated unless