Teach the 'opt' tool about '-Os' and '-Oz', corresponding to the Clang

options, to enable easier testing of the innards of LLVM that are
enabled by such optimization strategies.

Note that this doesn't provide the (much needed) function attribute
support for -Oz (as opposed to -Os), but still seems like a positive
step to better test the logic that Clang currently relies on.

Patch by Patrik Hägglund.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156913 91177308-0d34-0410-b5e6-96231b3b80d8

test/Other/optimize-options.ll

@@ -0,0 +1,8 @@
+;RUN: opt -S -O1 -debug-pass=Arguments |& FileCheck %s
+;RUN: opt -S -O2 -debug-pass=Arguments |& FileCheck %s
+;RUN: opt -S -Os -debug-pass=Arguments |& FileCheck %s
+;RUN: opt -S -Oz -debug-pass=Arguments |& FileCheck %s
+;RUN: opt -S -O3 -debug-pass=Arguments |& FileCheck %s
+
+; Just check that we get a non-empty set of passes for each -O opton.
+;CHECK: Pass Arguments: {{.*}} -print-module

tools/opt/opt.cpp

@@ -104,15 +104,23 @@ StandardLinkOpts("std-link-opts",
 
 static cl::opt<bool>
 OptLevelO1("O1",
-           cl::desc("Optimization level 1. Similar to llvm-gcc -O1"));
+           cl::desc("Optimization level 1. Similar to clang -O1"));
 
 static cl::opt<bool>
 OptLevelO2("O2",
-           cl::desc("Optimization level 2. Similar to llvm-gcc -O2"));
+           cl::desc("Optimization level 2. Similar to clang -O2"));
+
+static cl::opt<bool>
+OptLevelOs("Os",
+           cl::desc("Like -O2 with extra optimizations for size. Similar to clang -Os"));
+
+static cl::opt<bool>
+OptLevelOz("Oz",
+           cl::desc("Like -Os but reduces code size further. Similar to clang -Oz"));
 
 static cl::opt<bool>
 OptLevelO3("O3",
-           cl::desc("Optimization level 3. Similar to llvm-gcc -O3"));
+           cl::desc("Optimization level 3. Similar to clang -O3"));
 
 static cl::opt<std::string>
 TargetTriple("mtriple", cl::desc("Override target triple for module"));
@@ -409,16 +417,21 @@ static inline void addPass(PassManagerBase &PM, Pass *P) {
 ///
 /// OptLevel - Optimization Level
 static void AddOptimizationPasses(PassManagerBase &MPM,FunctionPassManager &FPM,
-                                  unsigned OptLevel) {
+                                  unsigned OptLevel, unsigned SizeLevel) {
   FPM.add(createVerifierPass());                  // Verify that input is correct
 
   PassManagerBuilder Builder;
   Builder.OptLevel = OptLevel;
+  Builder.SizeLevel = SizeLevel;
 
   if (DisableInline) {
     // No inlining pass
   } else if (OptLevel > 1) {
     unsigned Threshold = 225;
+    if (SizeLevel == 1)      // -Os
+      Threshold = 75;
+    else if (SizeLevel == 2) // -Oz
+      Threshold = 25;
     if (OptLevel > 2)
       Threshold = 275;
     Builder.Inliner = createFunctionInliningPass(Threshold);
@@ -571,7 +584,7 @@ int main(int argc, char **argv) {
     Passes.add(TD);
 
   OwningPtr<FunctionPassManager> FPasses;
-  if (OptLevelO1 || OptLevelO2 || OptLevelO3) {
+  if (OptLevelO1 || OptLevelO2 || OptLevelOs || OptLevelOz || OptLevelO3) {
     FPasses.reset(new FunctionPassManager(M.get()));
     if (TD)
       FPasses->add(new TargetData(*TD));
@@ -617,17 +630,27 @@ int main(int argc, char **argv) {
     }
 
     if (OptLevelO1 && OptLevelO1.getPosition() < PassList.getPosition(i)) {
-      AddOptimizationPasses(Passes, *FPasses, 1);
+      AddOptimizationPasses(Passes, *FPasses, 1, 0);
       OptLevelO1 = false;
     }
 
     if (OptLevelO2 && OptLevelO2.getPosition() < PassList.getPosition(i)) {
-      AddOptimizationPasses(Passes, *FPasses, 2);
+      AddOptimizationPasses(Passes, *FPasses, 2, 0);
       OptLevelO2 = false;
     }
 
+    if (OptLevelOs && OptLevelOs.getPosition() < PassList.getPosition(i)) {
+      AddOptimizationPasses(Passes, *FPasses, 2, 1);
+      OptLevelOs = false;
+    }
+
+    if (OptLevelOz && OptLevelOz.getPosition() < PassList.getPosition(i)) {
+      AddOptimizationPasses(Passes, *FPasses, 2, 2);
+      OptLevelOz = false;
+    }
+
     if (OptLevelO3 && OptLevelO3.getPosition() < PassList.getPosition(i)) {
-      AddOptimizationPasses(Passes, *FPasses, 3);
+      AddOptimizationPasses(Passes, *FPasses, 3, 0);
       OptLevelO3 = false;
     }
 
@@ -682,15 +705,21 @@ int main(int argc, char **argv) {
   }
 
   if (OptLevelO1)
-    AddOptimizationPasses(Passes, *FPasses, 1);
+    AddOptimizationPasses(Passes, *FPasses, 1, 0);
 
   if (OptLevelO2)
-    AddOptimizationPasses(Passes, *FPasses, 2);
+    AddOptimizationPasses(Passes, *FPasses, 2, 0);
+
+  if (OptLevelOs)
+    AddOptimizationPasses(Passes, *FPasses, 2, 1);
+
+  if (OptLevelOz)
+    AddOptimizationPasses(Passes, *FPasses, 2, 2);
 
   if (OptLevelO3)
-    AddOptimizationPasses(Passes, *FPasses, 3);
+    AddOptimizationPasses(Passes, *FPasses, 3, 0);
 
-  if (OptLevelO1 || OptLevelO2 || OptLevelO3) {
+  if (OptLevelO1 || OptLevelO2 || OptLevelOs || OptLevelOz || OptLevelO3) {
     FPasses->doInitialization();
     for (Module::iterator F = M->begin(), E = M->end(); F != E; ++F)
       FPasses->run(*F);