#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Utils/FunctionComparator.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
#include <algorithm>
#include <cassert>
#include <iterator>
/// analyzed again.
std::vector<WeakTrackingVH> Deferred;
+ /// Set of values marked as used in llvm.used and llvm.compiler.used.
+ SmallPtrSet<GlobalValue *, 4> Used;
+
#ifndef NDEBUG
/// Checks the rules of order relation introduced among functions set.
/// Returns true, if check has been passed, and false if failed.
bool MergeFunctions::runOnModule(Module &M) {
bool Changed = false;
+ SmallVector<GlobalValue *, 4> UsedV;
+ collectUsedGlobalVariables(M, UsedV, /*CompilerUsed=*/false);
+ collectUsedGlobalVariables(M, UsedV, /*CompilerUsed=*/true);
+ Used.insert(UsedV.begin(), UsedV.end());
+
// All functions in the module, ordered by hash. Functions with a unique
// hash value are easily eliminated.
std::vector<std::pair<FunctionComparator::FunctionHash, Function *>>
FnTree.clear();
FNodesInTree.clear();
GlobalNumbers.clear();
+ Used.clear();
return Changed;
}
// For better debugability, under MergeFunctionsPDI, we do not modify G's
// call sites to point to F even when within the same translation unit.
if (!G->isInterposable() && !MergeFunctionsPDI) {
- if (G->hasGlobalUnnamedAddr()) {
+ // Functions referred to by llvm.used/llvm.compiler.used are special:
+ // there are uses of the symbol name that are not visible to LLVM,
+ // usually from inline asm.
+ if (G->hasGlobalUnnamedAddr() && !Used.contains(G)) {
// G might have been a key in our GlobalNumberState, and it's illegal
// to replace a key in ValueMap<GlobalValue *> with a non-global.
GlobalNumbers.erase(G);
--- /dev/null
+; RUN: opt -S -mergefunc < %s | FileCheck %s
+
+@llvm.compiler.used = appending global [1 x i8*] [i8* bitcast (i32 (i32)* @a to i8*)], section "llvm.metadata"
+
+define internal i32 @a(i32 %a) unnamed_addr {
+ %b = xor i32 %a, 0
+ %c = xor i32 %b, 0
+ ret i32 %c
+}
+
+define i32 @b(i32 %a) unnamed_addr {
+ %b = xor i32 %a, 0
+ %c = xor i32 %b, 0
+ ret i32 %c
+}
+
+define i32 @c(i32 %a) unnamed_addr {
+ %b = tail call i32 @a(i32 %a)
+ ret i32 %b
+}
+
+; CHECK-LABEL: @llvm.compiler.used = appending global [1 x i8*] [i8* bitcast (i32 (i32)* @a to i8*)], section "llvm.metadata"
+
+; CHECK-LABEL: define i32 @b(i32 %a) unnamed_addr
+; CHECK-NEXT: xor
+; CHECK-NEXT: xor
+; CHECK-NEXT: ret
+
+; CHECK-LABEL: define i32 @c(i32 %a) unnamed_addr
+; CHECK-NEXT: tail call i32 @b(i32 %a)
+; CHECK-NEXT: ret
+
+; CHECK-LABEL: define internal i32 @a(i32 %0) unnamed_addr
+; CHECK-NEXT: tail call i32 @b(i32 %0)
+; CHECK-NEXT: ret