X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=docs%2Ftutorial%2FJITTutorial2.html;h=262457274d08d504205e40ddf0d13c91e0f02bd3;hb=317bd709bdd119a286e4c2e10b59202dc7e81a13;hp=ba72ea2abb014c1f19e8fb765b778c0f7242a89a;hpb=729eb14ae8b1a1002a212a99cdc411659670fbd4;p=oota-llvm.git diff --git a/docs/tutorial/JITTutorial2.html b/docs/tutorial/JITTutorial2.html index ba72ea2abb0..262457274d0 100644 --- a/docs/tutorial/JITTutorial2.html +++ b/docs/tutorial/JITTutorial2.html @@ -56,7 +56,7 @@ unsigned gcd(unsigned x, unsigned y) { #include <llvm/PassManager.h> #include <llvm/Analysis/Verifier.h> #include <llvm/Assembly/PrintModulePass.h> -#include <llvm/Support/LLVMBuilder.h> +#include <llvm/Support/IRBuilder.h> using namespace llvm; @@ -70,7 +70,8 @@ int main(int argc, char**argv) { PassManager PM; PM.add(new PrintModulePass(&llvm::cout)); PM.run(*Mod); - + + delete Mod; return 0; } @@ -98,11 +99,11 @@ Module* makeLLVMModule() { 
-  BasicBlock* entry = new BasicBlock("entry", gcd);
-  BasicBlock* ret = new BasicBlock("return", gcd);
-  BasicBlock* cond_false = new BasicBlock("cond_false", gcd);
-  BasicBlock* cond_true = new BasicBlock("cond_true", gcd);
-  BasicBlock* cond_false_2 = new BasicBlock("cond_false", gcd);
+  BasicBlock* entry = BasicBlock::Create("entry", gcd);
+  BasicBlock* ret = BasicBlock::Create("return", gcd);
+  BasicBlock* cond_false = BasicBlock::Create("cond_false", gcd);
+  BasicBlock* cond_true = BasicBlock::Create("cond_true", gcd);
+  BasicBlock* cond_false_2 = BasicBlock::Create("cond_false", gcd);
@@ -110,13 +111,13 @@ Module* makeLLVMModule() { 
-  LLVMBuilder builder(entry);
+  IRBuilder builder(entry);
   Value* xEqualsY = builder.CreateICmpEQ(x, y, "tmp");
   builder.CreateCondBr(xEqualsY, ret, cond_false);
-

Our next block, ret, is pretty simple: it just returns the value of x. Recall that this block is only reached if x == y, so this is the correct behavior. Notice that instead of creating a new LLVMBuilder for each block, we can use SetInsertPoint to retarget our existing one. This saves on construction and memory allocation costs.

+

Our next block, ret, is pretty simple: it just returns the value of x. Recall that this block is only reached if x == y, so this is the correct behavior. Notice that instead of creating a new IRBuilder for each block, we can use SetInsertPoint to retarget our existing one. This saves on construction and memory allocation costs.

@@ -125,7 +126,15 @@ Module* makeLLVMModule() {
-

cond_false is a more interesting block: we now know that x != y, so we must branch again to determine which of x and y is larger. This is achieved using the ICmpULT instruction, which stands for integer comparison for unsigned less-than. In LLVM, integer types do not carry sign; a 32-bit integer pseudo-register can interpreted as signed or unsigned without casting. Whether a signed or unsigned interpretation is desired is specified in the instruction. This is why several instructions in the LLVM IR, such as integer less-than, include a specifier for signed or unsigned.

+

cond_false is a more interesting block: we now know that x +!= y, so we must branch again to determine which of x +and y is larger. This is achieved using the ICmpULT +instruction, which stands for integer comparison for unsigned +less-than. In LLVM, integer types do not carry sign; a 32-bit integer +pseudo-register can be interpreted as signed or unsigned without casting. +Whether a signed or unsigned interpretation is desired is specified in the +instruction. This is why several instructions in the LLVM IR, such as integer +less-than, include a specifier for signed or unsigned.

Also note that we're again making use of LLVM's automatic name uniquing, this time at a register level. We've deliberately chosen to name every instruction "tmp" to illustrate that LLVM will give them all unique names without getting confused.

@@ -166,7 +175,7 @@ Module* makeLLVMModule() { 
-# c++ -g tut2.cpp `llvm-config --cppflags --ldflags --libs core` -o tut2
+# c++ -g tut2.cpp `llvm-config --cxxflags --ldflags --libs core` -o tut2
 # ./tut2