[flang] Correct bug in literal CHARACTER constant names

[clementval]

Summary

The names of CHARACTER strings were being truncated leading to invalid
collisions and other failures. This change makes sure to use the entire
string as the seed for the unique name.

This patch is part of the upstreaming effort from fir-dev branch.

Co-authored-by: Eric Schweitz <[e-mail]>

[jeanPerier]

LGTM

flang/lib/Lower/ConvertExpr.cpp

genScalarLit(const Fortran::evaluate::Scalar<Fortran::evaluate::Type<
     // When in an initializer context, construct the literal op itself and do
     // not construct another constant object in rodata.
     if (inInitializer)
       return fir::CharBoxValue{consLit().getResult(), lenp};
 
     // Otherwise, the string is in a plain old expression so "outline" the value
     // by hashconsing it to a constant literal object.
 
-    std::string globalName =
-        fir::factory::uniqueCGIdent("cl", (const char *)value.c_str());
+    auto size =
+        converter.getKindMap().getCharacterBitsize(KIND) / 8 * value.size();
+    llvm::StringRef strVal(reinterpret_cast<const char *>(value.c_str()), size);
+    std::string globalName = fir::factory::uniqueCGIdent("cl", strVal);
     fir::GlobalOp global = builder.getNamedGlobal(globalName);
     if (!global)
       global = builder.createGlobalConstant(
           getLoc(), type, globalName,
           [&](fir::FirOpBuilder &builder) {
             fir::StringLitOp str = consLit();
             builder.create<fir::HasValueOp>(getLoc(), str);
           },

flang/test/Lower/array-wide-char.f90

 ! CHECK-LABEL: @_QFsub1ECwiggle = internal constant [63 x i32] [i32 119,
 ! CHECK-SAME: i32 105, i32 103, i32 103, i32 108, i32 101, i32 32, i32 32,
 ! CHECK: @_QQcl[[inline:.*]] = linkonce constant [63 x i32] [i32 119, i32 105, i32 103, i32 103, i32 108, i32 101, i32 32,
 
 ! CHECK-LABEL: define void @_QQmain()
 ! CHECK: call void @_QPaction_on_char4(ptr @_QFEarr, i64 10)
 
 ! CHECK-LABEL: define void @_QPsub1(
-! CHECK: call void @_QPsub2(ptr @_QQcl.77, i64 63)
+! CHECK: call void @_QPsub2(ptr @_QQcl[[inline]], i64 63)