diff options
author | Keno Fischer <keno@alumni.harvard.edu> | 2017-04-06 19:26:22 +0000 |
---|---|---|
committer | Keno Fischer <keno@alumni.harvard.edu> | 2017-04-06 19:26:22 +0000 |
commit | 93e3e80c72090628ca63a13e2f05395de89b8662 (patch) | |
tree | 8d5e8495eead901bd20f38c4e0e3768573815626 /lib | |
parent | e4f931e960a32b85f15a74ff478580ddddc29af2 (diff) |
[StripDeadDebugInfo] Drop dead CUs entirely
Summary:
Prior to this while it would delete the dead DIGlobalVariables, it would
leave dead DICompileUnits and everything referenced therefrom. For a bit
bitcode file with thousands of compile units those dead nodes easily
outnumbered the real ones. Clean that up.
Reviewed By: aprantl
Differential Revision: https://reviews.llvm.org/D31720
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299692 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Transforms/IPO/StripSymbols.cpp | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/lib/Transforms/IPO/StripSymbols.cpp b/lib/Transforms/IPO/StripSymbols.cpp index 8f6f161428e..4d52f5f3110 100644 --- a/lib/Transforms/IPO/StripSymbols.cpp +++ b/lib/Transforms/IPO/StripSymbols.cpp @@ -323,6 +323,15 @@ bool StripDeadDebugInfo::runOnModule(Module &M) { LiveGVs.insert(GVE); } + std::set<DICompileUnit *> LiveCUs; + // Any CU referenced from a function is live. + for (Function &F : M.functions()) { + DISubprogram *SP = F.getSubprogram(); + if (SP && SP->getUnit()) + LiveCUs.insert(SP->getUnit()); + } + + bool HasDeadCUs = false; for (DICompileUnit *DIC : F.compile_units()) { // Create our live global variable list. bool GlobalVariableChange = false; @@ -341,6 +350,11 @@ bool StripDeadDebugInfo::runOnModule(Module &M) { GlobalVariableChange = true; } + if (!LiveGlobalVariables.empty()) + LiveCUs.insert(DIC); + else if (!LiveCUs.count(DIC)) + HasDeadCUs = true; + // If we found dead global variables, replace the current global // variable list with our new live global variable list. if (GlobalVariableChange) { @@ -352,5 +366,16 @@ bool StripDeadDebugInfo::runOnModule(Module &M) { LiveGlobalVariables.clear(); } + if (HasDeadCUs) { + // Delete the old node and replace it with a new one + NamedMDNode *NMD = M.getOrInsertNamedMetadata("llvm.dbg.cu"); + NMD->clearOperands(); + if (!LiveCUs.empty()) { + for (DICompileUnit *CU : LiveCUs) + NMD->addOperand(CU); + } + Changed = true; + } + return Changed; } |