[IR] Fix ignoring non-global-value-max-name-size in ValueSymbolTable::makeUniqueName(). (#89057)

E.g. during inlining new symbol name can be duplicated and then
`ValueSymbolTable::makeUniqueName()` will add unique suffix, exceeding
the `non-global-value-max-name-size` restriction.

Also fixed `unsigned` type of the option to `int` since `ValueSymbolTable`'
constructor can use `-1` value that means unrestricted name size.

Author: dfukalov

llvm/lib/IR/Function.cpp

@@ -79,7 +79,7 @@ using ProfileCount = Function::ProfileCount;
 // are not in the public header file...
 template class llvm::SymbolTableListTraits<BasicBlock>;
 
-static cl::opt<unsigned> NonGlobalValueMaxNameSize(
+static cl::opt<int> NonGlobalValueMaxNameSize(
     "non-global-value-max-name-size", cl::Hidden, cl::init(1024),
     cl::desc("Maximum size for the name of non-global values."));
 

llvm/lib/IR/ValueSymbolTable.cpp

@@ -43,23 +43,34 @@ ValueSymbolTable::~ValueSymbolTable() {
 ValueName *ValueSymbolTable::makeUniqueName(Value *V,
                                             SmallString<256> &UniqueName) {
   unsigned BaseSize = UniqueName.size();
+  bool AppenDot = false;
+  if (auto *GV = dyn_cast<GlobalValue>(V)) {
+    // A dot is appended to mark it as clone during ABI demangling so that
+    // for example "_Z1fv" and "_Z1fv.1" both demangle to "f()", the second
+    // one being a clone.
+    // On NVPTX we cannot use a dot because PTX only allows [A-Za-z0-9_$] for
+    // identifiers. This breaks ABI demangling but at least ptxas accepts and
+    // compiles the program.
+    const Module *M = GV->getParent();
+    if (!(M && Triple(M->getTargetTriple()).isNVPTX()))
+      AppenDot = true;
+  }
+
   while (true) {
     // Trim any suffix off and append the next number.
     UniqueName.resize(BaseSize);
     raw_svector_ostream S(UniqueName);
-    if (auto *GV = dyn_cast<GlobalValue>(V)) {
-      // A dot is appended to mark it as clone during ABI demangling so that
-      // for example "_Z1fv" and "_Z1fv.1" both demangle to "f()", the second
-      // one being a clone.
-      // On NVPTX we cannot use a dot because PTX only allows [A-Za-z0-9_$] for
-      // identifiers. This breaks ABI demangling but at least ptxas accepts and
-      // compiles the program.
-      const Module *M = GV->getParent();
-      if (!(M && Triple(M->getTargetTriple()).isNVPTX()))
-        S << ".";
-    }
+    if (AppenDot)
+      S << ".";
     S << ++LastUnique;
 
+    // Retry if MaxNameSize has been exceeded.
+    if (MaxNameSize > -1 && UniqueName.size() > (size_t)MaxNameSize) {
+      assert(BaseSize >= UniqueName.size() - (size_t)MaxNameSize &&
+             "Can't generate unique name: MaxNameSize is too small.");
+      BaseSize -= UniqueName.size() - (size_t)MaxNameSize;
+      continue;
+    }
     // Try insert the vmap entry with this suffix.
     auto IterBool = vmap.insert(std::make_pair(UniqueName.str(), V));
     if (IterBool.second)

llvm/test/Assembler/non-global-value-max-name-size-2.ll

@@ -0,0 +1,23 @@
+; RUN: opt < %s -S -passes='always-inline' -non-global-value-max-name-size=5 | opt -non-global-value-max-name-size=5 -passes=verify -disable-output
+
+; Opt should not generate too long name for labels during inlining.
+
+define internal i32 @inner(i32 %flag) alwaysinline {
+entry:
+  %icmp = icmp slt i32 %flag, 0
+  br i1 %icmp, label %one, label %two
+
+one:
+  ret i32 42
+
+two:
+  ret i32 44
+}
+
+define i32 @outer(i32 %x) {
+entry:
+  %call1 = call i32 @inner(i32 %x)
+  %call2 = call i32 @inner(i32 %x)
+  %ret = add i32 %call1, %call2
+  ret i32 %ret
+}

llvm/test/Bitcode/value-with-long-name-dbg.ll

@@ -0,0 +1,11 @@
+; REQUIRES: asserts
+; Force the size to be small to check assertion message.
+; RUN: not --crash opt -S %s -O2 -o - -non-global-value-max-name-size=0 2>&1 | FileCheck %s
+; CHECK: Can't generate unique name: MaxNameSize is too small.
+
+define i32 @f(i32 %a, i32 %b) {
+  %c = add i32 %a, %b
+  %d = add i32 %c, %a
+  %e = add i32 %d, %b
+  ret i32 %e
+}

llvm/test/Bitcode/value-with-long-name.ll

@@ -1,10 +1,10 @@
 ; Check the size of generated variable when no option is set
 ; RUN: opt -S %s -O2 -o - | FileCheck -check-prefix=CHECK-LONG %s
+; RUN: opt -S %s -O2 -o - -non-global-value-max-name-size=-1 | FileCheck -check-prefix=CHECK-LONG %s
 ; CHECK-LONG: %{{[a-z]{4}[a-z]+}}
 
 ; Then check we correctly cap the size of newly generated non-global values name
 ; Force the size to be small so that the check works on release and debug build
-; RUN: opt -S %s -O2 -o - -non-global-value-max-name-size=0 | FileCheck -check-prefix=CHECK-SHORT %s
 ; RUN: opt -S %s -O2 -o - -non-global-value-max-name-size=1 | FileCheck -check-prefix=CHECK-SHORT %s
 ; CHECK-SHORT-NOT: %{{[a-z][a-z]+}}
 
@@ -14,5 +14,3 @@ define i32 @f(i32 %a, i32 %b) {
   %e = add i32 %d, %b
   ret i32 %e
 }
-
-