From 69783d2696b1c3c41b1b97865f0c89da8f4ad7cf Mon Sep 17 00:00:00 2001 From: Peter Collingbourne Date: Fri, 2 Aug 2019 17:43:45 +0000 Subject: [PATCH] CodeGen: Don't follow aliases when extracting type info. This fixes a crash in the case where the type info object is an alias pointing to a non-zero offset within a global or is otherwise unanalyzable by the stripPointerCasts() function. Looking through the alias is not the right thing to do anyway for similar reasons as D65118. Differential Revision: https://reviews.llvm.org/D65314 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@367696 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/Analysis.cpp | 2 +- test/CodeGen/X86/typeid-alias.ll | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+), 1 deletion(-) create mode 100644 test/CodeGen/X86/typeid-alias.ll diff --git a/lib/CodeGen/Analysis.cpp b/lib/CodeGen/Analysis.cpp index d158e70b86a..e72938ba9be 100644 --- a/lib/CodeGen/Analysis.cpp +++ b/lib/CodeGen/Analysis.cpp @@ -156,7 +156,7 @@ void llvm::computeValueLLTs(const DataLayout &DL, Type &Ty, /// ExtractTypeInfo - Returns the type info, possibly bitcast, encoded in V. GlobalValue *llvm::ExtractTypeInfo(Value *V) { - V = V->stripPointerCasts(); + V = V->stripPointerCastsNoFollowAliases(); GlobalValue *GV = dyn_cast(V); GlobalVariable *Var = dyn_cast(V); diff --git a/test/CodeGen/X86/typeid-alias.ll b/test/CodeGen/X86/typeid-alias.ll new file mode 100644 index 00000000000..885ab703b8b --- /dev/null +++ b/test/CodeGen/X86/typeid-alias.ll @@ -0,0 +1,18 @@ +; Test that we don't crash in the case where the type info object is an +; alias pointing to a non-zero offset within a global. + +; RUN: llc < %s | FileCheck %s + +target triple = "x86_64-unknown-linux-gnu" + +%struct.exception = type { i8, i8, i32, i8*, i8*, i32, i8* } +@g = global %struct.exception zeroinitializer +@a = alias %struct.exception, %struct.exception* inttoptr (i64 add (i64 ptrtoint (%struct.exception* @g to i64), i64 1297036692682702848) to %struct.exception*) + +define i32 @typeid() { + ; CHECK: movl $1, %eax + %eh_typeid = tail call i32 @llvm.eh.typeid.for( i8* getelementptr (%struct.exception, %struct.exception* @a, i32 0, i32 0)) + ret i32 %eh_typeid +} + +declare i32 @llvm.eh.typeid.for(i8*) -- 2.40.0