Author: johannes
Date: Wed Jan 16 13:59:28 2008
New Revision: 46088
URL: http://llvm.org/viewvc/llvm-project?rev=46088&view=rev
Log:
Do not mark EH tables no-dead-strip unless the
associated function is so marked.
Modified:
llvm/trunk/include/llvm/CodeGen/MachineModuleInfo.h
llvm/trunk/lib/CodeGen/DwarfWriter.cpp
llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp
Modified: llvm/trunk/include/llvm/CodeGen/MachineModuleInfo.h
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineModuleInfo.h?rev=46088&r1=46087&r2=46088&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineModuleInfo.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineModuleInfo.h Wed Jan 16 13:59:28 2008
@@ -35,6 +35,7 @@
#include "llvm/Support/DataTypes.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/UniqueVector.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/GlobalValue.h"
#include "llvm/Pass.h"
@@ -1037,6 +1038,10 @@
// common EH frames.
std::vector<Function *> Personalities;
+ // UsedFunctions - the functions in the llvm.used list in a more easily
+ // searchable format.
+ SmallPtrSet<const Function *, 32> UsedFunctions;
+
bool CallsEHReturn;
bool CallsUnwindInit;
public:
@@ -1235,6 +1240,11 @@
return Personalities;
}
+ // UsedFunctions - Return set of the functions in the llvm.used list.
+ const SmallPtrSet<const Function *, 32>& getUsedFunctions() const {
+ return UsedFunctions;
+ }
+
/// addCatchTypeInfo - Provide the catch typeinfo for a landing pad.
///
void addCatchTypeInfo(MachineBasicBlock *LandingPad,
Modified: llvm/trunk/lib/CodeGen/DwarfWriter.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/DwarfWriter.cpp?rev=46088&r1=46087&r2=46088&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/DwarfWriter.cpp (original)
+++ llvm/trunk/lib/CodeGen/DwarfWriter.cpp Wed Jan 16 13:59:28 2008
@@ -2764,15 +2764,14 @@
bool hasCalls;
bool hasLandingPads;
std::vector<MachineMove> Moves;
- Function::LinkageTypes linkage;
+ const Function * function;
FunctionEHFrameInfo(const std::string &FN, unsigned Num, unsigned P,
bool hC, bool hL,
const std::vector<MachineMove> &M,
- Function::LinkageTypes l):
+ const Function *f):
FnName(FN), Number(Num), PersonalityIndex(P),
- hasCalls(hC), hasLandingPads(hL), Moves(M),
- linkage(l) { }
+ hasCalls(hC), hasLandingPads(hL), Moves(M), function (f) { }
};
std::vector<FunctionEHFrameInfo> EHFrames;
@@ -2869,19 +2868,21 @@
/// EmitEHFrame - Emit function exception frame information.
///
void EmitEHFrame(const FunctionEHFrameInfo &EHFrameInfo) {
+ Function::LinkageTypes linkage = EHFrameInfo.function->getLinkage();
+
Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection());
// Externally visible entry into the functions eh frame info.
// If the corresponding function is static, this should not be
// externally visible.
- if (EHFrameInfo.linkage != Function::InternalLinkage) {
+ if (linkage != Function::InternalLinkage) {
if (const char *GlobalEHDirective = TAI->getGlobalEHDirective())
O << GlobalEHDirective << EHFrameInfo.FnName << "\n";
}
// If corresponding function is weak definition, this should be too.
- if ((EHFrameInfo.linkage == Function::WeakLinkage ||
- EHFrameInfo.linkage == Function::LinkOnceLinkage) &&
+ if ((linkage == Function::WeakLinkage ||
+ linkage == Function::LinkOnceLinkage) &&
TAI->getWeakDefDirective())
O << TAI->getWeakDefDirective() << EHFrameInfo.FnName << "\n";
@@ -2889,12 +2890,17 @@
// omit the EH Frame, but some environments do not handle weak absolute
// symbols.
if (!EHFrameInfo.hasCalls &&
- ((EHFrameInfo.linkage != Function::WeakLinkage &&
- EHFrameInfo.linkage != Function::LinkOnceLinkage) ||
+ ((linkage != Function::WeakLinkage &&
+ linkage != Function::LinkOnceLinkage) ||
!TAI->getWeakDefDirective() ||
TAI->getSupportsWeakOmittedEHFrame()))
{
O << EHFrameInfo.FnName << " = 0\n";
+ // This name has no connection to the function, so it might get
+ // dead-stripped when the function is not, erroneously. Prohibit
+ // dead-stripping unconditionally.
+ if (const char *UsedDirective = TAI->getUsedDirective())
+ O << UsedDirective << EHFrameInfo.FnName << "\n\n";
} else {
O << EHFrameInfo.FnName << ":\n";
@@ -2941,10 +2947,16 @@
Asm->EmitAlignment(2);
EmitLabel("eh_frame_end", EHFrameInfo.Number);
- }
- if (const char *UsedDirective = TAI->getUsedDirective())
- O << UsedDirective << EHFrameInfo.FnName << "\n\n";
+ // If the function is marked used, this table should be also. We cannot
+ // make the mark unconditional in this case, since retaining the table
+ // also retains the function in this case, and there is code around
+ // that depends on unused functions (calling undefined externals) being
+ // dead-stripped to link correctly. Yes, there really is.
+ if (MMI->getUsedFunctions().count(EHFrameInfo.function))
+ if (const char *UsedDirective = TAI->getUsedDirective())
+ O << UsedDirective << EHFrameInfo.FnName << "\n\n";
+ }
}
/// EmitExceptionTable - Emit landing pads and actions.
@@ -3414,7 +3426,7 @@
MF->getFrameInfo()->hasCalls(),
!MMI->getLandingPads().empty(),
MMI->getFrameMoves(),
- MF->getFunction()->getLinkage()));
+ MF->getFunction()));
}
};
Modified: llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp?rev=46088&r1=46087&r2=46088&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineModuleInfo.cpp Wed Jan 16 13:59:28 2008
@@ -1552,6 +1552,21 @@
///
void MachineModuleInfo::AnalyzeModule(Module &M) {
SetupCompileUnits(M);
+
+ // Insert functions in the llvm.used array into UsedFunctions.
+ GlobalVariable *GV = M.getGlobalVariable("llvm.used");
+ if (!GV || !GV->hasInitializer()) return;
+
+ // Should be an array of 'i8*'.
+ ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
+ if (InitList == 0) return;
+
+ for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(InitList->getOperand(i)))
+ if (CE->getOpcode() == Instruction::BitCast)
+ if (Function *F = dyn_cast<Function>(CE->getOperand(0)))
+ UsedFunctions.insert(F);
+ }
}
/// needsFrameInfo - Returns true if we need to gather callee-saved register
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