[cfe-commits] r39927 - in /cfe/trunk/CodeGen: CGStmt.cpp CodeGenFunction.cpp CodeGenFunction.h
Chris Lattner
sabre at nondot.org
Mon Jul 16 14:28:46 PDT 2007
Author: lattner
Date: Mon Jul 16 16:28:45 2007
New Revision: 39927
URL: http://llvm.org/viewvc/llvm-project?rev=39927&view=rev
Log:
Implement break and continue. Patch by Anders Carlsson!
Modified:
cfe/trunk/CodeGen/CGStmt.cpp
cfe/trunk/CodeGen/CodeGenFunction.cpp
cfe/trunk/CodeGen/CodeGenFunction.h
Modified: cfe/trunk/CodeGen/CGStmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/CodeGen/CGStmt.cpp?rev=39927&r1=39926&r2=39927&view=diff
==============================================================================
--- cfe/trunk/CodeGen/CGStmt.cpp (original)
+++ cfe/trunk/CodeGen/CGStmt.cpp Mon Jul 16 16:28:45 2007
@@ -49,6 +49,9 @@
case Stmt::ReturnStmtClass: EmitReturnStmt(cast<ReturnStmt>(*S)); break;
case Stmt::DeclStmtClass: EmitDeclStmt(cast<DeclStmt>(*S)); break;
+
+ case Stmt::BreakStmtClass: EmitBreakStmt(); break;
+ case Stmt::ContinueStmtClass: EmitContinueStmt(); break;
}
}
@@ -126,8 +129,6 @@
}
void CodeGenFunction::EmitWhileStmt(const WhileStmt &S) {
- // FIXME: Handle continue/break.
-
// Emit the header for the loop, insert it, which will create an uncond br to
// it.
llvm::BasicBlock *LoopHeader = new llvm::BasicBlock("whilecond");
@@ -148,10 +149,15 @@
// As long as the condition is true, go to the loop body.
Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock);
+
+ // Store the blocks to use for break and continue.
+ BreakContinueStack.push_back(BreakContinue(ExitBlock, LoopHeader));
// Emit the loop body.
EmitBlock(LoopBody);
EmitStmt(S.getBody());
+
+ BreakContinueStack.pop_back();
// Cycle to the condition.
Builder.CreateBr(LoopHeader);
@@ -161,7 +167,6 @@
}
void CodeGenFunction::EmitDoStmt(const DoStmt &S) {
- // FIXME: Handle continue/break.
// TODO: "do {} while (0)" is common in macros, avoid extra blocks. Be sure
// to correctly handle break/continue though.
@@ -170,10 +175,19 @@
llvm::BasicBlock *LoopBody = new llvm::BasicBlock("dobody");
llvm::BasicBlock *AfterDo = new llvm::BasicBlock("afterdo");
EmitBlock(LoopBody);
+
+ llvm::BasicBlock *DoCond = new llvm::BasicBlock("docond");
+
+ // Store the blocks to use for break and continue.
+ BreakContinueStack.push_back(BreakContinue(AfterDo, DoCond));
// Emit the body of the loop into the block.
EmitStmt(S.getBody());
+ BreakContinueStack.pop_back();
+
+ EmitBlock(DoCond);
+
// C99 6.8.5.2: "The evaluation of the controlling expression takes place
// after each execution of the loop body."
@@ -190,17 +204,20 @@
}
void CodeGenFunction::EmitForStmt(const ForStmt &S) {
- // FIXME: Handle continue/break.
// FIXME: What do we do if the increment (f.e.) contains a stmt expression,
// which contains a continue/break?
-
+ // TODO: We could keep track of whether the loop body contains any
+ // break/continue statements and not create unnecessary blocks (like
+ // "afterfor" for a condless loop) if it doesn't.
+
// Evaluate the first part before the loop.
if (S.getInit())
EmitStmt(S.getInit());
// Start the loop with a block that tests the condition.
llvm::BasicBlock *CondBlock = new llvm::BasicBlock("forcond");
- llvm::BasicBlock *AfterFor = 0;
+ llvm::BasicBlock *AfterFor = new llvm::BasicBlock("afterfor");
+
EmitBlock(CondBlock);
// Evaluate the condition if present. If not, treat it as a non-zero-constant
@@ -212,7 +229,6 @@
// As long as the condition is true, iterate the loop.
llvm::BasicBlock *ForBody = new llvm::BasicBlock("forbody");
- AfterFor = new llvm::BasicBlock("afterfor");
Builder.CreateCondBr(BoolCondVal, ForBody, AfterFor);
EmitBlock(ForBody);
} else {
@@ -220,8 +236,24 @@
// body, just fall into it.
}
+ // If the for loop doesn't have an increment we can just use the
+ // condition as the continue block.
+ llvm::BasicBlock *ContinueBlock;
+ if (S.getInc())
+ ContinueBlock = new llvm::BasicBlock("forinc");
+ else
+ ContinueBlock = CondBlock;
+
+ // Store the blocks to use for break and continue.
+ BreakContinueStack.push_back(BreakContinue(AfterFor, ContinueBlock));
+
// If the condition is true, execute the body of the for stmt.
EmitStmt(S.getBody());
+
+ BreakContinueStack.pop_back();
+
+ if (S.getInc())
+ EmitBlock(ContinueBlock);
// If there is an increment, emit it next.
if (S.getInc())
@@ -230,11 +262,8 @@
// Finally, branch back up to the condition for the next iteration.
Builder.CreateBr(CondBlock);
- // Emit the fall-through block if there is any.
- if (AfterFor)
- EmitBlock(AfterFor);
- else
- EmitBlock(new llvm::BasicBlock());
+ // Emit the fall-through block.
+ EmitBlock(AfterFor);
}
/// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
@@ -284,3 +313,19 @@
for (const Decl *Decl = S.getDecl(); Decl; Decl = Decl->getNextDeclarator())
EmitDecl(*Decl);
}
+
+void CodeGenFunction::EmitBreakStmt() {
+ assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!");
+
+ llvm::BasicBlock *Block = BreakContinueStack.back().BreakBlock;
+ Builder.CreateBr(Block);
+ EmitBlock(new llvm::BasicBlock());
+}
+
+void CodeGenFunction::EmitContinueStmt() {
+ assert(!BreakContinueStack.empty() && "continue stmt not in a loop!");
+
+ llvm::BasicBlock *Block = BreakContinueStack.back().ContinueBlock;
+ Builder.CreateBr(Block);
+ EmitBlock(new llvm::BasicBlock());
+}
Modified: cfe/trunk/CodeGen/CodeGenFunction.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/CodeGen/CodeGenFunction.cpp?rev=39927&r1=39926&r2=39927&view=diff
==============================================================================
--- cfe/trunk/CodeGen/CodeGenFunction.cpp (original)
+++ cfe/trunk/CodeGen/CodeGenFunction.cpp Mon Jul 16 16:28:45 2007
@@ -94,6 +94,9 @@
else
Builder.CreateRet(llvm::UndefValue::get(CurFn->getReturnType()));
+ assert(BreakContinueStack.empty() &&
+ "mismatched push/pop in break/continue stack!");
+
// Verify that the function is well formed.
assert(!verifyFunction(*CurFn));
}
Modified: cfe/trunk/CodeGen/CodeGenFunction.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/CodeGen/CodeGenFunction.h?rev=39927&r1=39926&r2=39927&view=diff
==============================================================================
--- cfe/trunk/CodeGen/CodeGenFunction.h (original)
+++ cfe/trunk/CodeGen/CodeGenFunction.h Mon Jul 16 16:28:45 2007
@@ -15,6 +15,7 @@
#define CODEGEN_CODEGENFUNCTION_H
#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/LLVMBuilder.h"
#include <vector>
@@ -175,6 +176,18 @@
/// LabelMap - This keeps track of the LLVM basic block for each C label.
llvm::DenseMap<const LabelStmt*, llvm::BasicBlock*> LabelMap;
+
+ // BreakContinueStack - This keeps track of where break and continue
+ // statements should jump to.
+ struct BreakContinue {
+ BreakContinue(llvm::BasicBlock *bb, llvm::BasicBlock *cb)
+ : BreakBlock(bb), ContinueBlock(cb) {}
+
+ llvm::BasicBlock *BreakBlock;
+ llvm::BasicBlock *ContinueBlock;
+ };
+ llvm::SmallVector<BreakContinue, 8> BreakContinueStack;
+
public:
CodeGenFunction(CodeGenModule &cgm);
@@ -254,7 +267,9 @@
void EmitForStmt(const ForStmt &S);
void EmitReturnStmt(const ReturnStmt &S);
void EmitDeclStmt(const DeclStmt &S);
-
+ void EmitBreakStmt();
+ void EmitContinueStmt();
+
//===--------------------------------------------------------------------===//
// LValue Expression Emission
//===--------------------------------------------------------------------===//
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