[llvm] r227261 - SymbolRewriter: allow rewriting with comdats

[Saleem Abdulrasool]

On Tue, Jan 27, 2015 at 2:57 PM, Saleem Abdulrasool <compnerd at compnerd.org>
wrote:

> Author: compnerd
> Date: Tue Jan 27 16:57:39 2015
> New Revision: 227261
>
> URL: http://llvm.org/viewvc/llvm-project?rev=227261&view=rev
> Log:
> SymbolRewriter: allow rewriting with comdats
>
> COMDATs must be identically named to the symbol.  When support for COMDATs
> was
> introduced, the symbol rewriter was not updated, resulting in rewriting
> failing
> for symbols which were placed into COMDATs.  This corrects the behaviour
> and
> adds test cases for this.
>

Hi Hans,

I think we should merge this and the prior change (227260) for the 3.6
release as it makes this unusable in many cases after the support for
comdats was added near the end of the branch point.


> Modified:
>     llvm/trunk/lib/Transforms/Utils/SymbolRewriter.cpp
>     llvm/trunk/test/SymbolRewriter/rewrite.ll
>     llvm/trunk/test/SymbolRewriter/rewrite.map
>
> Modified: llvm/trunk/lib/Transforms/Utils/SymbolRewriter.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SymbolRewriter.cpp?rev=227261&r1=227260&r2=227261&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Utils/SymbolRewriter.cpp (original)
> +++ llvm/trunk/lib/Transforms/Utils/SymbolRewriter.cpp Tue Jan 27 16:57:39
> 2015
> @@ -79,6 +79,19 @@ static cl::list<std::string> RewriteMapF
>
>  namespace llvm {
>  namespace SymbolRewriter {
> +void rewriteComdat(Module &M, GlobalObject *GO, const std::string &Source,
> +                   const std::string &Target) {
> +  if (Comdat *CD = GO->getComdat()) {
> +    auto &Comdats = M.getComdatSymbolTable();
> +
> +    Comdat *C = M.getOrInsertComdat(Target);
> +    C->setSelectionKind(CD->getSelectionKind());
> +    GO->setComdat(C);
> +
> +    Comdats.erase(Comdats.find(Source));
> +  }
> +}
> +
>  template <RewriteDescriptor::Type DT, typename ValueType,
>            ValueType *(llvm::Module::*Get)(StringRef) const>
>  class ExplicitRewriteDescriptor : public RewriteDescriptor {
> @@ -102,10 +115,14 @@ template <RewriteDescriptor::Type DT, ty
>  bool ExplicitRewriteDescriptor<DT, ValueType,
> Get>::performOnModule(Module &M) {
>    bool Changed = false;
>    if (ValueType *S = (M.*Get)(Source)) {
> +    if (GlobalObject *GO = dyn_cast<GlobalObject>(S))
> +      rewriteComdat(M, GO, Source, Target);
> +
>      if (Value *T = (M.*Get)(Target))
>        S->setValueName(T->getValueName());
>      else
>        S->setName(Target);
> +
>      Changed = true;
>    }
>    return Changed;
> @@ -148,6 +165,9 @@ performOnModule(Module &M) {
>      if (C.getName() == Name)
>        continue;
>
> +    if (GlobalObject *GO = dyn_cast<GlobalObject>(&C))
> +      rewriteComdat(M, GO, C.getName(), Name);
> +
>      if (Value *V = (M.*Get)(Name))
>        C.setValueName(V->getValueName());
>      else
>
> Modified: llvm/trunk/test/SymbolRewriter/rewrite.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/SymbolRewriter/rewrite.ll?rev=227261&r1=227260&r2=227261&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/SymbolRewriter/rewrite.ll (original)
> +++ llvm/trunk/test/SymbolRewriter/rewrite.ll Tue Jan 27 16:57:39 2015
> @@ -28,12 +28,40 @@ entry:
>    ret void
>  }
>
> +$source_comdat_function = comdat any
> +define dllexport void @source_comdat_function()
> comdat($source_comdat_function) {
> +entry:
> +  ret void
> +}
> +
> +$source_comdat_function_1 = comdat exactmatch
> +define dllexport void @source_comdat_function_1()
> comdat($source_comdat_function_1) {
> +entry:
> +  ret void
> +}
> +
> +$source_comdat_variable = comdat largest
> + at source_comdat_variable = global i32 32, comdat($source_comdat_variable)
> +
> +$source_comdat_variable_1 = comdat noduplicates
> + at source_comdat_variable_1 = global i32 64,
> comdat($source_comdat_variable_1)
> +
> +; CHECK: $target_comdat_function = comdat any
> +; CHECK: $target_comdat_function_1 = comdat exactmatch
> +; CHECK: $target_comdat_variable = comdat largest
> +; CHECK: $target_comdat_variable_1 = comdat noduplicates
> +
>  ; CHECK: @target_variable = external global i32
>  ; CHECK-NOT: @source_variable = external global i32
>  ; CHECK: @target_pattern_variable = external global i32
>  ; CHECK-NOT: @source_pattern_variable = external global i32
>  ; CHECK: @target_pattern_multiple_variable_matches = external global i32
>  ; CHECK-NOT: @source_pattern_multiple_variable_matches = external global
> i32
> +; CHECK: @target_comdat_variable = global i32 32, comdat
> +; CHECK-NOT: @source_comdat_variable = global i32 32, comdat
> +; CHECK: @target_comdat_variable_1 = global i32 64, comdat
> +; CHECK-NOT: @source_comdat_variable_1 = global i32 64, comdat
> +
>  ; CHECK: declare void @target_function()
>  ; CHECK-NOT: declare void @source_function()
>  ; CHECK: declare void @target_pattern_function()
> @@ -57,3 +85,8 @@ entry:
>  ; CHECK:   ret i32 %res
>  ; CHECK: }
>
> +; CHECK: define dllexport void @target_comdat_function() comdat
> +; CHECK-NOT: define dllexport void @source_comdat_function() comdat
> +; CHECK: define dllexport void @target_comdat_function_1() comdat
> +; CHECK-NOT: define dllexport void @source_comdat_function_1() comdat
> +
>
> Modified: llvm/trunk/test/SymbolRewriter/rewrite.map
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/SymbolRewriter/rewrite.map?rev=227261&r1=227260&r2=227261&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/SymbolRewriter/rewrite.map (original)
> +++ llvm/trunk/test/SymbolRewriter/rewrite.map Tue Jan 27 16:57:39 2015
> @@ -44,3 +44,23 @@ global alias: {
>    target: _ZN1SD1Ev,
>  }
>
> +function: {
> +  source: source_comdat_function,
> +  target: target_comdat_function,
> +}
> +
> +function: {
> +  source: source_comdat_function_(.*),
> +  transform: target_comdat_function_\1,
> +}
> +
> +global variable: {
> +  source: source_comdat_variable,
> +  target: target_comdat_variable,
> +}
> +
> +global variable: {
> +  source: source_comdat_variable_(.*),
> +  transform: target_comdat_variable_\1,
> +}
> +
>
>
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-- 
Saleem Abdulrasool
compnerd (at) compnerd (dot) org
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