[WIP] Initial code for module flags.
Module flags are key-value pairs associated with the module. They include a
'behavior' value, indicating how module flags react when mergine two
files. Normally, it's just the union of the two module flags. But if two module
flags have the same key, then the resulting flags are dictated by the behaviors.
Allowable behaviors are:
Error
Emits an error if two values disagree.
Warning
Emits a warning if two values disagree.
Require
Emits an error when the specified value is not present
or doesn't have the specified value. It is an error for
two (or more) llvm.module.flags with the same ID to have
the Require behavior but different values. There may be
multiple Require flags per ID.
Override
Uses the specified value if the two values disagree. It
is an error for two (or more) llvm.module.flags with the
same ID to have the Override behavior but different
values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150300 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Linker/LinkModules.cpp b/lib/Linker/LinkModules.cpp
index 73ae6ad..8e2fc4f 100644
--- a/lib/Linker/LinkModules.cpp
+++ b/lib/Linker/LinkModules.cpp
@@ -16,8 +16,10 @@
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
-#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Path.h"
#include "llvm/Transforms/Utils/Cloning.h"
@@ -406,11 +408,19 @@
}
void computeTypeMapping();
+ bool categorizeModuleFlagNodes(const NamedMDNode *ModFlags,
+ DenseMap<MDString*, MDNode*> &ErrorNode,
+ DenseMap<MDString*, MDNode*> &WarningNode,
+ DenseMap<MDString*, MDNode*> &OverrideNode,
+ DenseMap<MDString*,
+ SmallSetVector<MDNode*, 8> > &RequireNodes,
+ SmallSetVector<MDString*, 16> &SeenIDs);
bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV);
bool linkGlobalProto(GlobalVariable *SrcGV);
bool linkFunctionProto(Function *SrcF);
bool linkAliasProto(GlobalAlias *SrcA);
+ bool linkModuleFlagsMetadata();
void linkAppendingVarInit(const AppendingVarInfo &AVI);
void linkGlobalInits();
@@ -938,8 +948,11 @@
/// linkNamedMDNodes - Insert all of the named mdnodes in Src into the Dest
/// module.
void ModuleLinker::linkNamedMDNodes() {
+ const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(),
E = SrcM->named_metadata_end(); I != E; ++I) {
+ // Don't link module flags here. Do them separately.
+ if (&*I == SrcModFlags) continue;
NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName());
// Add Src elements into Dest node.
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
@@ -947,10 +960,175 @@
RF_None, &TypeMap));
}
}
+
+/// categorizeModuleFlagNodes -
+bool ModuleLinker::
+categorizeModuleFlagNodes(const NamedMDNode *ModFlags,
+ DenseMap<MDString*, MDNode*> &ErrorNode,
+ DenseMap<MDString*, MDNode*> &WarningNode,
+ DenseMap<MDString*, MDNode*> &OverrideNode,
+ DenseMap<MDString*,
+ SmallSetVector<MDNode*, 8> > &RequireNodes,
+ SmallSetVector<MDString*, 16> &SeenIDs) {
+ bool HasErr = false;
+
+ for (unsigned I = 0, E = ModFlags->getNumOperands(); I != E; ++I) {
+ MDNode *Op = ModFlags->getOperand(I);
+ assert(Op->getNumOperands() == 3 && "Invalid module flag metadata!");
+ assert(isa<ConstantInt>(Op->getOperand(0)) &&
+ "Module flag's first operand must be an integer!");
+ assert(isa<MDString>(Op->getOperand(1)) &&
+ "Module flag's second operand must be an MDString!");
+
+ ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0));
+ MDString *ID = cast<MDString>(Op->getOperand(1));
+ Value *Val = Op->getOperand(2);
+ switch (Behavior->getZExtValue()) {
+ default:
+ assert(false && "Invalid behavior in module flag metadata!");
+ break;
+ case Module::Error: {
+ MDNode *&ErrNode = ErrorNode[ID];
+ if (!ErrNode) ErrNode = Op;
+ if (ErrNode->getOperand(2) != Val)
+ HasErr = emitError("Linking module flags '" + ID->getString() +
+ "': IDs have conflicting values!");
+ break;
+ }
+ case Module::Warning: {
+ MDNode *&WarnNode = WarningNode[ID];
+ if (!WarnNode) WarnNode = Op;
+ if (WarnNode->getOperand(2) != Val)
+ errs() << "WARNING: Linking module flags '" << ID->getString()
+ << "': IDs have conflicting values!";
+ break;
+ }
+ case Module::Require: RequireNodes[ID].insert(Op); break;
+ case Module::Override: {
+ MDNode *&OvrNode = OverrideNode[ID];
+ if (!OvrNode) OvrNode = Op;
+ if (OvrNode->getOperand(2) != Val)
+ HasErr = emitError("Linking module flags '" + ID->getString() +
+ "': IDs have conflicting override values!");
+ break;
+ }
+ }
+
+ SeenIDs.insert(ID);
+ }
+
+ return HasErr;
+}
+
+/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest
+/// module.
+bool ModuleLinker::linkModuleFlagsMetadata() {
+ const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
+ if (!SrcModFlags) return false;
+
+ NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata();
+
+ // If the destination module doesn't have module flags yet, then just copy
+ // over the source module's flags.
+ if (DstModFlags->getNumOperands() == 0) {
+ for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
+ DstModFlags->addOperand(SrcModFlags->getOperand(I));
+
+ return false;
+ }
+
+ bool HasErr = false;
+
+ // Otherwise, we have to merge them based on their behaviors. First,
+ // categorize all of the nodes in the modules' module flags. If an error or
+ // warning occurs, then emit the appropriate message(s).
+ DenseMap<MDString*, MDNode*> ErrorNode;
+ DenseMap<MDString*, MDNode*> WarningNode;
+ DenseMap<MDString*, MDNode*> OverrideNode;
+ DenseMap<MDString*, SmallSetVector<MDNode*, 8> > RequireNodes;
+ SmallSetVector<MDString*, 16> SeenIDs;
+
+ HasErr |= categorizeModuleFlagNodes(SrcModFlags, ErrorNode, WarningNode,
+ OverrideNode, RequireNodes, SeenIDs);
+ HasErr |= categorizeModuleFlagNodes(DstModFlags, ErrorNode, WarningNode,
+ OverrideNode, RequireNodes, SeenIDs);
+
+ // Check that there isn't both an error and warning node for a flag.
+ for (SmallSetVector<MDString*, 16>::iterator
+ I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
+ MDString *ID = *I;
+ if (ErrorNode[ID] && WarningNode[ID])
+ HasErr = emitError("Linking module flags '" + ID->getString() +
+ "': IDs have conflicting behaviors");
+ }
+
+ // Early exit if we had an error.
+ if (HasErr) return true;
+
+ // Get the destination's module flags ready for new operands.
+ DstModFlags->dropAllReferences();
+
+ // Add all of the module flags to the destination module.
+ DenseMap<MDString*, SmallVector<MDNode*, 4> > AddedNodes;
+ for (SmallSetVector<MDString*, 16>::iterator
+ I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
+ MDString *ID = *I;
+ if (OverrideNode[ID]) {
+ DstModFlags->addOperand(OverrideNode[ID]);
+ AddedNodes[ID].push_back(OverrideNode[ID]);
+ } else if (ErrorNode[ID]) {
+ DstModFlags->addOperand(ErrorNode[ID]);
+ AddedNodes[ID].push_back(ErrorNode[ID]);
+ } else if (WarningNode[ID]) {
+ DstModFlags->addOperand(WarningNode[ID]);
+ AddedNodes[ID].push_back(WarningNode[ID]);
+ }
+
+ for (SmallSetVector<MDNode*, 8>::iterator
+ II = RequireNodes[ID].begin(), IE = RequireNodes[ID].end();
+ II != IE; ++II)
+ DstModFlags->addOperand(*II);
+ }
+
+ // Now check that all of the requirements have been satisfied.
+ for (SmallSetVector<MDString*, 16>::iterator
+ I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
+ MDString *ID = *I;
+ SmallSetVector<MDNode*, 8> &Set = RequireNodes[ID];
+
+ for (SmallSetVector<MDNode*, 8>::iterator
+ II = Set.begin(), IE = Set.end(); II != IE; ++II) {
+ MDNode *Node = *II;
+ assert(isa<MDNode>(Node->getOperand(2)) &&
+ "Module flag's third operand must be an MDNode!");
+ MDNode *Val = cast<MDNode>(Node->getOperand(2));
+
+ MDString *ReqID = cast<MDString>(Val->getOperand(0));
+ Value *ReqVal = Val->getOperand(1);
+
+ bool HasValue = false;
+ for (SmallVectorImpl<MDNode*>::iterator
+ RI = AddedNodes[ReqID].begin(), RE = AddedNodes[ReqID].end();
+ RI != RE; ++RI) {
+ MDNode *ReqNode = *RI;
+ if (ReqNode->getOperand(2) == ReqVal) {
+ HasValue = true;
+ break;
+ }
+ }
+
+ if (!HasValue)
+ HasErr = emitError("Linking module flags '" + ReqID->getString() +
+ "': does not have the required value!");
+ }
+ }
+
+ return HasErr;
+}
bool ModuleLinker::run() {
- assert(DstM && "Null Destination module");
- assert(SrcM && "Null Source Module");
+ assert(DstM && "Null destination module");
+ assert(SrcM && "Null source module");
// Inherit the target data from the source module if the destination module
// doesn't have one already.
@@ -1030,7 +1208,6 @@
// Link in the function bodies that are defined in the source module into
// DstM.
for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) {
-
// Skip if not linking from source.
if (DoNotLinkFromSource.count(SF)) continue;
@@ -1048,11 +1225,15 @@
// Resolve all uses of aliases with aliasees.
linkAliasBodies();
- // Remap all of the named mdnoes in Src into the DstM module. We do this
+ // Remap all of the named MDNodes in Src into the DstM module. We do this
// after linking GlobalValues so that MDNodes that reference GlobalValues
// are properly remapped.
linkNamedMDNodes();
+ // Merge the module flags into the DstM module.
+ if (linkModuleFlagsMetadata())
+ return true;
+
// Process vector of lazily linked in functions.
bool LinkedInAnyFunctions;
do {