[llvm-c] Remove bindings for creating legacy passes

Legacy passes are only supported for codegen, and I don't believe
it's possible to write backends using the C API, so we should drop
all of those. Reduces the number of places that need to be modified
when removing legacy passes.

Differential Revision: https://reviews.llvm.org/D144970

Author: nikic

clang/docs/tools/clang-formatted-files.txt

@@ -5713,8 +5713,6 @@ llvm/include/llvm-c/OrcEE.h
 llvm/include/llvm-c/Remarks.h
 llvm/include/llvm-c/Types.h
 llvm/include/llvm-c/Transforms/PassBuilder.h
-llvm/include/llvm-c/Transforms/Scalar.h
-llvm/include/llvm-c/Transforms/Vectorize.h
 llvm/lib/Analysis/CodeMetrics.cpp
 llvm/lib/Analysis/CycleAnalysis.cpp
 llvm/lib/Analysis/DDGPrinter.cpp

llvm/docs/ReleaseNotes.rst

@@ -145,6 +145,8 @@ Changes to the C API
 
 * ``LLVMContextSetOpaquePointers``, a temporary API to pin to legacy typed
   pointer, has been removed.
+* Functions for adding legacy passes like ``LLVMAddInstructionCombiningPass``
+  have been removed.
 
 Changes to the FastISel infrastructure
 --------------------------------------

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

@@ -12,7 +12,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm-c/Transforms/IPO.h"
 #include "llvm-c/Initialization.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/InitializePasses.h"
@@ -34,11 +33,3 @@ void llvm::initializeIPO(PassRegistry &Registry) {
 void LLVMInitializeIPO(LLVMPassRegistryRef R) {
   initializeIPO(*unwrap(R));
 }
-
-void LLVMAddDeadArgEliminationPass(LLVMPassManagerRef PM) {
-  unwrap(PM)->add(createDeadArgEliminationPass());
-}
-
-void LLVMAddAlwaysInlinerPass(LLVMPassManagerRef PM) {
-  unwrap(PM)->add(llvm::createAlwaysInlinerLegacyPass());
-}

llvm/include/llvm-c/Transforms/InstCombine.h

@@ -34,7 +34,6 @@
 
 #include "InstCombineInternal.h"
 #include "llvm-c/Initialization.h"
-#include "llvm-c/Transforms/InstCombine.h"
 #include "llvm/ADT/APInt.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
@@ -4760,7 +4759,3 @@ FunctionPass *llvm::createInstructionCombiningPass() {
 FunctionPass *llvm::createInstructionCombiningPass(unsigned MaxIterations) {
   return new InstructionCombiningPass(MaxIterations);
 }
-
-void LLVMAddInstructionCombiningPass(LLVMPassManagerRef PM) {
-  unwrap(PM)->add(createInstructionCombiningPass());
-}