[LLVM-C] Improve Bindings to The Internalize Pass

[CodaFi]

Summary

Adds a binding to the internalize pass that allows the caller to pass a function pointer that acts as the visibility-preservation predicate. Previously, one could only pass an unsigned value (not LLVMBool?) that directed the pass to consider "main" or not.

[whitequark]

LGTM. Maybe a comment about expected lifetime of Context would be useful, but it seems fairly obvious.

[CodaFi]

Document the lifetime of the context parameter

[kren1]

Is there a plan to commit this? I would like to add the OCaml binding for it ...

llvm/trunk/include/llvm-c/Transforms/IPO.h

 void LLVMAddPruneEHPass(LLVMPassManagerRef PM);
 
 /** See llvm::createIPSCCPPass function. */
 void LLVMAddIPSCCPPass(LLVMPassManagerRef PM);
 
 /** See llvm::createInternalizePass function. */
 void LLVMAddInternalizePass(LLVMPassManagerRef, unsigned AllButMain);
 
+/**
+ * Create and add the internalize pass to the given pass manager with the
+ * provided preservation callback.
+ *
+ * The context parameter is forwarded to the callback on each invocation.
+ * As such, it is the responsibility of the caller to extend its lifetime
+ * until execution of this pass has finished.
+ *
+ * @see llvm::createInternalizePass function.
+ */
+void LLVMAddInternalizePassWithMustPreservePredicate(
+    LLVMPassManagerRef PM,
+    void *Context,
+    LLVMBool (*MustPreserve)(LLVMValueRef, void *));
+
 /** See llvm::createStripDeadPrototypesPass function. */
 void LLVMAddStripDeadPrototypesPass(LLVMPassManagerRef PM);
 
 /** See llvm::createStripSymbolsPass function. */
 void LLVMAddStripSymbolsPass(LLVMPassManagerRef PM);
 
 /**
  * @}
  */
 
 #ifdef __cplusplus
 }
 #endif /* defined(__cplusplus) */
 
 #endif

llvm/trunk/lib/Transforms/IPO/IPO.cpp

 
 void LLVMAddInternalizePass(LLVMPassManagerRef PM, unsigned AllButMain) {
   auto PreserveMain = [=](const GlobalValue &GV) {
     return AllButMain && GV.getName() == "main";
   };
   unwrap(PM)->add(createInternalizePass(PreserveMain));
 }
 
+void LLVMAddInternalizePassWithMustPreservePredicate(
+    LLVMPassManagerRef PM,
+    void *Context,
+    LLVMBool (*Pred)(LLVMValueRef, void *)) {
+  unwrap(PM)->add(createInternalizePass([=](const GlobalValue &GV) {
+    return Pred(wrap(&GV), Context) == 0 ? false : true;
+  }));
+}
+
 void LLVMAddStripDeadPrototypesPass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createStripDeadPrototypesPass());
 }
 
 void LLVMAddStripSymbolsPass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createStripSymbolsPass());
 }