Fixup goto codegen in and around VLAs.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@64014 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index 939ebec..42512d1 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -164,6 +164,7 @@
}
if (llvm::Value *V = StackSaveValues.pop_back_val()) {
+ StackDepth = V;
V = Builder.CreateLoad(V, "tmp");
llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stackrestore);
@@ -186,6 +187,41 @@
Builder.SetInsertPoint(BB);
}
+void CodeGenFunction::EmitStackUpdate(const LabelStmt &S) {
+ if (StackDepthMap.find(&S) == StackDepthMap.end()) {
+ // If we can't find it, just remember the depth now,
+ // so we can validate it later.
+ // FIXME: We need to save a place to insert the adjustment,
+ // if needed, here, sa that later in EmitLabel, we can
+ // backpatch the adjustment into that place, instead of
+ // saying unsupported.
+ StackDepthMap[&S] = StackDepth;
+ return;
+ }
+
+ // Find applicable stack depth, if any...
+ llvm::Value *V = StackDepthMap[&S];
+ // V can be 0 here, if it is, be sure to start searching from the
+ // top of the function, as we want the next save after that point.
+ for (unsigned int i = 0; i < StackSaveValues.size(); ++i)
+ if (StackSaveValues[i] == V) {
+ // The actual depth is actually in the next used slot, if any.
+ while (++i < StackSaveValues.size()
+ && (V = StackSaveValues[i]) == 0) ;
+ // If there were no other depth changes, we don't need any
+ // adjustments.
+ if (V) {
+ V = Builder.CreateLoad(V, "tmp");
+ // and restore it.
+ llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::stackrestore);
+ Builder.CreateCall(F, V);
+ }
+ } else
+ // FIXME: Move to semq and assert here, codegen isn't the right
+ // time to be checking.
+ CGM.ErrorUnsupported(&S, "invalid goto to VLA scope that has finished");
+}
+
void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) {
// Emit a branch from the current block to the target one if this
// was a real block. If this was just a fall-through block after a
@@ -205,6 +241,22 @@
void CodeGenFunction::EmitLabel(const LabelStmt &S) {
llvm::BasicBlock *NextBB = getBasicBlockForLabel(&S);
+ if (StackDepthMap.find(&S) == StackDepthMap.end()) {
+ // We need to remember the stack depth so that we can readjust the
+ // stack back to the right depth for this label if we want to
+ // transfer here from a different depth.
+ StackDepthMap[&S] = StackDepth;
+ } else {
+ if (StackDepthMap[&S] != StackDepth) {
+ // FIXME: Sema needs to ckeck for jumps that cross decls with
+ // initializations for C++, and all VLAs, not just the first in
+ // a block that does a stacksave.
+ // FIXME: We need to save a place to insert the adjustment
+ // when we do a EmitStackUpdate on a forward jump, and then
+ // backpatch the adjustment into that place.
+ CGM.ErrorUnsupported(&S, "forward goto inside scope with VLA");
+ }
+ }
EmitBlock(NextBB);
}
@@ -221,18 +273,16 @@
return;
}
- for (unsigned i = 0; i < StackSaveValues.size(); i++) {
- if (StackSaveValues[i]) {
- CGM.ErrorUnsupported(&S, "goto inside scope with VLA");
- return;
- }
- }
-
// If this code is reachable then emit a stop point (if generating
// debug info). We have to do this ourselves because we are on the
// "simple" statement path.
if (HaveInsertPoint())
EmitStopPoint(&S);
+
+ // We need to adjust the stack, if the destination was (will be) at
+ // a different depth.
+ EmitStackUpdate(*S.getLabel());
+
EmitBranch(getBasicBlockForLabel(S.getLabel()));
}
@@ -330,14 +380,13 @@
Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock);
// Store the blocks to use for break and continue.
- BreakContinueStack.push_back(BreakContinue(ExitBlock, LoopHeader,
- ObjCEHStack.size()));
+ BreakContinuePush(ExitBlock, LoopHeader);
// Emit the loop body.
EmitBlock(LoopBody);
EmitStmt(S.getBody());
- BreakContinueStack.pop_back();
+ BreakContinuePop();
// Cycle to the condition.
EmitBranch(LoopHeader);
@@ -364,13 +413,12 @@
llvm::BasicBlock *DoCond = createBasicBlock("do.cond");
// Store the blocks to use for break and continue.
- BreakContinueStack.push_back(BreakContinue(AfterDo, DoCond,
- ObjCEHStack.size()));
+ BreakContinuePush(AfterDo, DoCond);
// Emit the body of the loop into the block.
EmitStmt(S.getBody());
- BreakContinueStack.pop_back();
+ BreakContinuePop();
EmitBlock(DoCond);
@@ -443,13 +491,12 @@
ContinueBlock = CondBlock;
// Store the blocks to use for break and continue.
- BreakContinueStack.push_back(BreakContinue(AfterFor, ContinueBlock,
- ObjCEHStack.size()));
+ BreakContinuePush(AfterFor, ContinueBlock);
// If the condition is true, execute the body of the for stmt.
EmitStmt(S.getBody());
- BreakContinueStack.pop_back();
+ BreakContinuePop();
// If there is an increment, emit it next.
if (S.getInc()) {
@@ -678,12 +725,11 @@
llvm::BasicBlock *ContinueBlock = NULL;
if (!BreakContinueStack.empty())
ContinueBlock = BreakContinueStack.back().ContinueBlock;
- BreakContinueStack.push_back(BreakContinue(NextBlock, ContinueBlock,
- ObjCEHStack.size()));
+ BreakContinuePush(NextBlock, ContinueBlock);
// Emit switch body.
EmitStmt(S.getBody());
- BreakContinueStack.pop_back();
+ BreakContinuePop();
// Update the default block in case explicit case range tests have
// been chained on top.