diff options
| -rw-r--r-- | lib/Transforms/IPO/DeadArgumentElimination.cpp | 13 | ||||
| -rw-r--r-- | test/Transforms/DeadArgElim/linkage.ll | 21 |
2 files changed, 34 insertions, 0 deletions
diff --git a/lib/Transforms/IPO/DeadArgumentElimination.cpp b/lib/Transforms/IPO/DeadArgumentElimination.cpp index 6ee6162..8621f1a 100644 --- a/lib/Transforms/IPO/DeadArgumentElimination.cpp +++ b/lib/Transforms/IPO/DeadArgumentElimination.cpp @@ -357,6 +357,19 @@ bool DAE::RemoveDeadArgumentsFromCallers(Function &Fn) if (Fn.hasLocalLinkage() && !Fn.getFunctionType()->isVarArg()) return false; + // If a function seen at compile time is not necessarily the one linked to + // the binary being built, it is illegal to change the actual arguments + // passing to it. These functions can be captured by isWeakForLinker(). + // *NOTE* that mayBeOverridden() is insufficient for this purpose as it + // dosen't include linkage types like AvailableExternallyLinkage and + // LinkOnceODRLinkage. Take link_odr* as an example, it indicates a set of + // *EQUIVALENT* globals that can be merged at link-time. However, the + // semantic of *EQUIVALENT*-functions includes parameters. Changing + // parameters breaks the assumption. + // + if (Fn.isWeakForLinker()) + return false; + if (Fn.use_empty()) return false; diff --git a/test/Transforms/DeadArgElim/linkage.ll b/test/Transforms/DeadArgElim/linkage.ll new file mode 100644 index 0000000..f475484 --- /dev/null +++ b/test/Transforms/DeadArgElim/linkage.ll @@ -0,0 +1,21 @@ +; RUN: opt < %s -deadargelim -S | FileCheck %s + +; rdar://11546243 +%struct.A = type { i8 } + +define available_externally void @_Z17externallyDefinedP1A(%struct.A* %a) { +entry: + call void @_Z3foov() + ret void +} + +declare void @_Z3foov() + +define void @_Z4testP1A(%struct.A* %a) { +; CHECK: @_Z4testP1A +; CHECK: @_Z17externallyDefinedP1A(%struct.A* %a) + +entry: + call void @_Z17externallyDefinedP1A(%struct.A* %a) + ret void +} |