[llvm-dwp] Start error messages with a lowercase letter.

We usually start error messages with lowercase letters and most of them
in llvm-dwp follow that rule. This patch fixes a few messages that
started with capital letters.

Differential revision: https://reviews.llvm.org/D76277

llvm/test/tools/llvm-dwp/X86/duplicate.test

@@ -18,10 +18,10 @@ RUN:   | FileCheck --check-prefix=DWO1DWP %s
 
 Build from a, b, and c.c all containing a single void() func by the name of the file.
 
-DWOS: error: Duplicate DWO ID ({{.*}}) in 'c.c' and 'c.c'{{$}}
-1DWP: error: Duplicate DWO ID ({{.*}}) in 'c.c' (from '{{.*}}ac.dwp') and 'c.c'{{$}}
-2DWP: error: Duplicate DWO ID ({{.*}}) in 'c.c' and 'c.c' (from '{{.*}}bc.dwp'){{$}}
+DWOS: error: duplicate DWO ID ({{.*}}) in 'c.c' and 'c.c'{{$}}
+1DWP: error: duplicate DWO ID ({{.*}}) in 'c.c' (from '{{.*}}ac.dwp') and 'c.c'{{$}}
+2DWP: error: duplicate DWO ID ({{.*}}) in 'c.c' and 'c.c' (from '{{.*}}bc.dwp'){{$}}
 
-DWODWOS: error: Duplicate DWO ID ({{.*}}) in 'c.c' and 'c.c'{{$}}
-DWO1DWP: error: Duplicate DWO ID ({{.*}}) in 'c.c' (from 'c.dwo' in '{{.*}}ac.dwp') and 'c.c'{{$}}
-DWO2DWP: error: Duplicate DWO ID ({{.*}}) in 'c.c' and 'c.c' (from 'c.dwo' in '{{.*}}bc.dwp'){{$}}
+DWODWOS: error: duplicate DWO ID ({{.*}}) in 'c.c' and 'c.c'{{$}}
+DWO1DWP: error: duplicate DWO ID ({{.*}}) in 'c.c' (from 'c.dwo' in '{{.*}}ac.dwp') and 'c.c'{{$}}
+DWO2DWP: error: duplicate DWO ID ({{.*}}) in 'c.c' and 'c.c' (from 'c.dwo' in '{{.*}}bc.dwp'){{$}}

llvm/test/tools/llvm-dwp/X86/gcc_type.test

@@ -5,4 +5,4 @@ CHECK: Type Unit
 CHECK: Type Unit
 
 // Check that llvm-dwp can parse DW_FORM_string for CU name
-DUP: Duplicate DWO ID ({{.*}}) in 'a.cpp' and 'a.cpp'
+DUP: duplicate DWO ID ({{.*}}) in 'a.cpp' and 'a.cpp'

llvm/test/tools/llvm-dwp/X86/invalid_cu_index.test

@@ -1,3 +1,3 @@
 RUN: not llvm-dwp %p/../Inputs/invalid_cu_index/x.dwp -o %t 2>&1 | FileCheck %s
 
-CHECK: error: Failed to parse cu_index
+CHECK: error: failed to parse cu_index

llvm/test/tools/llvm-dwp/X86/missing_tu_index.test

@@ -1,3 +1,3 @@
 RUN: not llvm-dwp %p/../Inputs/missing_tu_index/x.dwp -o %t 2>&1 | FileCheck %s
 
-CHECK: error: Failed to parse tu_index
+CHECK: error: failed to parse tu_index

llvm/tools/llvm-dwp/llvm-dwp.cpp

@@ -479,7 +479,7 @@ static Error
 buildDuplicateError(const std::pair<uint64_t, UnitIndexEntry> &PrevE,
                     const CompileUnitIdentifiers &ID, StringRef DWPName) {
   return make_error<DWPError>(
-      std::string("Duplicate DWO ID (") + utohexstr(PrevE.first) + ") in " +
+      std::string("duplicate DWO ID (") + utohexstr(PrevE.first) + ") in " +
       buildDWODescription(PrevE.second.Name, PrevE.second.DWPName,
                           PrevE.second.DWOName) +
       " and " + buildDWODescription(ID.Name, DWPName, ID.DWOName));
@@ -596,7 +596,7 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
     DWARFUnitIndex CUIndex(DW_SECT_INFO);
     DataExtractor CUIndexData(CurCUIndexSection, Obj.isLittleEndian(), 0);
     if (!CUIndex.parse(CUIndexData))
-      return make_error<DWPError>("Failed to parse cu_index");
+      return make_error<DWPError>("failed to parse cu_index");
 
     for (const DWARFUnitIndex::Entry &E : CUIndex.getRows()) {
       auto *I = E.getOffsets();
@@ -631,7 +631,7 @@ static Error write(MCStreamer &Out, ArrayRef<std::string> Inputs) {
       DWARFUnitIndex TUIndex(DW_SECT_TYPES);
       DataExtractor TUIndexData(CurTUIndexSection, Obj.isLittleEndian(), 0);
       if (!TUIndex.parse(TUIndexData))
-        return make_error<DWPError>("Failed to parse tu_index");
+        return make_error<DWPError>("failed to parse tu_index");
       addAllTypesFromDWP(Out, TypeIndexEntries, TUIndex, TypesSection,
                          CurTypesSection.front(), CurEntry,
                          ContributionOffsets[DW_SECT_TYPES - DW_SECT_INFO]);