Add TargetRegistry::lookupTarget.

 - This is a simplified mechanism which just looks up a target based on the
   target triple, with a few additional flags.

 - Remove getClosestStaticTargetForModule, the moral equivalent is now:
     lookupTarget(Mod->getTargetTriple, true, false, ...);

 - This no longer does the fuzzy matching with target data (based on endianness
   and pointer width) that getClosestStaticTargetForModule was doing, but this
   was deemed unnecessary.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@77111 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 85 deletions

diff --git a/lib/Support/TargetRegistry.cpp b/lib/Support/TargetRegistry.cpp
index f9026f12af..4558d2d215 100644
--- a/lib/Support/TargetRegistry.cpp
+++ b/lib/Support/TargetRegistry.cpp
@@ -7,6 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Module.h"
 #include "llvm/Target/TargetRegistry.h"
 #include "llvm/System/Host.h"
 #include <cassert>
@@ -19,9 +20,10 @@ TargetRegistry::iterator TargetRegistry::begin() {
   return iterator(FirstTarget);
 }
 
-const Target *
-TargetRegistry::getClosestStaticTargetForTriple(const std::string &TT,
-                                                std::string &Error) {
+const Target *TargetRegistry::lookupTarget(const std::string &TT,
+                                           bool FallbackToHost,
+                                           bool RequireJIT,
+                                           std::string &Error) {
   // Provide special warning when no targets are initialized.
   if (begin() == end()) {
     Error = "Unable to find target for this triple (no targets are registered)";
@@ -30,45 +32,10 @@ TargetRegistry::getClosestStaticTargetForTriple(const std::string &TT,
   const Target *Best = 0, *EquallyBest = 0;
   unsigned BestQuality = 0;
   for (iterator it = begin(), ie = end(); it != ie; ++it) {
-    if (unsigned Qual = it->TripleMatchQualityFn(TT)) {
-      if (!Best || Qual > BestQuality) {
-        Best = &*it;
-        EquallyBest = 0;
-        BestQuality = Qual;
-      } else if (Qual == BestQuality)
-        EquallyBest = &*it;
-    }
-  }
-
-  if (!Best) {
-    Error = "No available targets are compatible with this triple";
-    return 0;
-  }
-
-  // Otherwise, take the best target, but make sure we don't have two equally
-  // good best targets.
-  if (EquallyBest) {
-    Error = std::string("Cannot choose between targets \"") +
-      Best->Name  + "\" and \"" + EquallyBest->Name + "\"";
-    return 0;
-  }
-
-  return Best;
-}
-
-const Target *
-TargetRegistry::getClosestStaticTargetForModule(const Module &M,
-                                                std::string &Error) {
-  // Provide special warning when no targets are initialized.
-  if (begin() == end()) {
-    Error = "Unable to find target for this module (no targets are registered)";
-    return 0;
-  }
+    if (RequireJIT && !it->hasJIT())
+      continue;
 
-  const Target *Best = 0, *EquallyBest = 0;
-  unsigned BestQuality = 0;
-  for (iterator it = begin(), ie = end(); it != ie; ++it) {
-    if (unsigned Qual = it->ModuleMatchQualityFn(M)) {
+    if (unsigned Qual = it->TripleMatchQualityFn(TT)) {
       if (!Best || Qual > BestQuality) {
         Best = &*it;
         EquallyBest = 0;
@@ -78,18 +45,18 @@ TargetRegistry::getClosestStaticTargetForModule(const Module &M,
     }
   }
 
-  // FIXME: This is a hack to ignore super weak matches like msil, etc. and look
-  // by host instead. They will be found again via the triple.
-  if (Best && BestQuality == 1)    
-    Best = EquallyBest = 0;
+  // FIXME: Hack. If we only have an extremely weak match and the client
+  // requested to fall back to the host, then ignore it and try again.
+  if (BestQuality == 1 && FallbackToHost)
+    Best = 0;
 
-  // If that failed, try looking up the host triple.
-  if (!Best)
-    Best = getClosestStaticTargetForTriple(sys::getHostTriple(), Error);
+  // Fallback to the host triple if we didn't find anything.
+  if (!Best && FallbackToHost)
+    return lookupTarget(sys::getHostTriple(), false, RequireJIT, Error);
 
   if (!Best) {
-    Error = "No available targets are compatible with this module";
-    return Best;
+    Error = "No available targets are compatible with this triple";
+    return 0;
   }
 
   // Otherwise, take the best target, but make sure we don't have two equally
@@ -103,41 +70,6 @@ TargetRegistry::getClosestStaticTargetForModule(const Module &M,
   return Best;
 }
 
-const Target *
-TargetRegistry::getClosestTargetForJIT(std::string &Error) {
-  std::string Triple = sys::getHostTriple();
-
-  // Provide special warning when no targets are initialized.
-  if (begin() == end()) {
-    Error = "No JIT is available for this host (no targets are registered)";
-    return 0;
-  }
-
-  const Target *Best = 0, *EquallyBest = 0;
-  unsigned BestQuality = 0;
-  for (iterator it = begin(), ie = end(); it != ie; ++it) {
-    if (!it->hasJIT())
-      continue;
-
-    if (unsigned Qual = it->TripleMatchQualityFn(Triple)) {
-      if (!Best || Qual > BestQuality) {
-        Best = &*it;
-        EquallyBest = 0;
-        BestQuality = Qual;
-      } else if (Qual == BestQuality)
-        EquallyBest = &*it;
-    }
-  }
-
-  if (!Best) {
-    Error = "No JIT is available for this host";
-    return 0;
-  }
-
-  // Return the best, ignoring ties.
-  return Best;
-}
-
 void TargetRegistry::RegisterTarget(Target &T,
                                     const char *Name,
                                     const char *ShortDesc,