Teaching llvm-tblgen to not emit a switch statement when there are no case statements.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186330 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/utils/TableGen/AsmMatcherEmitter.cpp b/utils/TableGen/AsmMatcherEmitter.cpp
index 218af21..b45d40a 100644
--- a/utils/TableGen/AsmMatcherEmitter.cpp
+++ b/utils/TableGen/AsmMatcherEmitter.cpp
@@ -114,6 +114,7 @@
#include <cassert>
#include <map>
#include <set>
+#include <sstream>
using namespace llvm;
static cl::opt<std::string>
@@ -2066,9 +2067,11 @@
OS << " if (A == B)\n";
OS << " return true;\n\n";
- OS << " switch (A) {\n";
- OS << " default:\n";
- OS << " return false;\n";
+ std::stringstream SS;
+ unsigned Count = 0;
+ SS << " switch (A) {\n";
+ SS << " default:\n";
+ SS << " return false;\n";
for (std::vector<ClassInfo*>::iterator it = Infos.begin(),
ie = Infos.end(); it != ie; ++it) {
ClassInfo &A = **it;
@@ -2084,21 +2087,35 @@
if (SuperClasses.empty())
continue;
+ ++Count;
- OS << "\n case " << A.Name << ":\n";
+ SS << "\n case " << A.Name << ":\n";
if (SuperClasses.size() == 1) {
- OS << " return B == " << SuperClasses.back() << ";\n";
+ SS << " return B == " << SuperClasses.back().str() << ";\n";
continue;
}
- OS << " switch (B) {\n";
- OS << " default: return false;\n";
- for (unsigned i = 0, e = SuperClasses.size(); i != e; ++i)
- OS << " case " << SuperClasses[i] << ": return true;\n";
- OS << " }\n";
+ if (!SuperClasses.empty()) {
+ SS << " switch (B) {\n";
+ SS << " default: return false;\n";
+ for (unsigned i = 0, e = SuperClasses.size(); i != e; ++i)
+ SS << " case " << SuperClasses[i].str() << ": return true;\n";
+ SS << " }\n";
+ } else {
+ // No case statement to emit
+ SS << " return false;\n";
+ }
}
- OS << " }\n";
+ SS << " }\n";
+
+ // If there were case statements emitted into the string stream, write them
+ // to the output stream, otherwise write the default.
+ if (Count)
+ OS << SS.str();
+ else
+ OS << " return false;\n";
+
OS << "}\n\n";
}
@@ -2194,18 +2211,24 @@
static void emitGetSubtargetFeatureName(AsmMatcherInfo &Info, raw_ostream &OS) {
OS << "// User-level names for subtarget features that participate in\n"
<< "// instruction matching.\n"
- << "static const char *getSubtargetFeatureName(unsigned Val) {\n"
- << " switch(Val) {\n";
- for (std::map<Record*, SubtargetFeatureInfo*>::const_iterator
- it = Info.SubtargetFeatures.begin(),
- ie = Info.SubtargetFeatures.end(); it != ie; ++it) {
- SubtargetFeatureInfo &SFI = *it->second;
- // FIXME: Totally just a placeholder name to get the algorithm working.
- OS << " case " << SFI.getEnumName() << ": return \""
- << SFI.TheDef->getValueAsString("PredicateName") << "\";\n";
+ << "static const char *getSubtargetFeatureName(unsigned Val) {\n";
+ if (!Info.SubtargetFeatures.empty()) {
+ OS << " switch(Val) {\n";
+ for (std::map<Record*, SubtargetFeatureInfo*>::const_iterator
+ it = Info.SubtargetFeatures.begin(),
+ ie = Info.SubtargetFeatures.end(); it != ie; ++it) {
+ SubtargetFeatureInfo &SFI = *it->second;
+ // FIXME: Totally just a placeholder name to get the algorithm working.
+ OS << " case " << SFI.getEnumName() << ": return \""
+ << SFI.TheDef->getValueAsString("PredicateName") << "\";\n";
+ }
+ OS << " default: return \"(unknown)\";\n";
+ OS << " }\n";
+ } else {
+ // Nothing to emit, so skip the switch
+ OS << " return \"(unknown)\";\n";
}
- OS << " default: return \"(unknown)\";\n";
- OS << " }\n}\n\n";
+ OS << "}\n\n";
}
/// emitComputeAvailableFeatures - Emit the function to compute the list of