[WinEH] Mark funclet entries and exits as clobbering all registers

Summary:
In this implementation, LiveIntervalAnalysis invents a few register
masks on basic block boundaries that preserve no registers. The nice
thing about this is that it prevents the prologue inserter from thinking
it needs to spill all XMM CSRs, because it doesn't see any explicit
physreg defs in the MI.

Reviewers: MatzeB, qcolombet, JosephTremoulet, majnemer

Subscribers: MatzeB, llvm-commits

Differential Revision: http://reviews.llvm.org/D14407

llvm-svn: 252318

2 files changed, 177 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/catchpad-regmask.ll b/llvm/test/CodeGen/X86/catchpad-regmask.ll
new file mode 100644
index 00000000000..fe3a238e173
--- /dev/null
+++ b/llvm/test/CodeGen/X86/catchpad-regmask.ll
@@ -0,0 +1,150 @@
+; RUN: llc < %s | FileCheck %s
+
+; Based on this code:
+;
+; extern "C" int array[4];
+; extern "C" void global_array(int idx1, int idx2, int idx3) {
+;   try {
+;     array[idx1] = 111;
+;     throw;
+;   } catch (...) {
+;     array[idx2] = 222;
+;   }
+;   array[idx3] = 333;
+; }
+; extern "C" __declspec(dllimport) int imported;
+; extern "C" void access_imported() {
+;   try {
+;     imported = 111;
+;     throw;
+;   } catch (...) {
+;     imported = 222;
+;   }
+;   imported = 333;
+; }
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc18.0.0"
+
+%eh.ThrowInfo = type { i32, i32, i32, i32 }
+
+@array = external global [4 x i32], align 16
+@imported = external dllimport global i32, align 4
+
+; Function Attrs: uwtable
+define void @global_array(i32 %idx1, i32 %idx2, i32 %idx3) #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+entry:
+  %idxprom = sext i32 %idx1 to i64
+  %arrayidx = getelementptr inbounds [4 x i32], [4 x i32]* @array, i64 0, i64 %idxprom
+  store i32 111, i32* %arrayidx, align 4, !tbaa !2
+  invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) #1
+          to label %unreachable unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %entry
+  %0 = catchpad [i8* null, i32 64, i8* null]
+          to label %catch unwind label %catchendblock
+
+catch:                                            ; preds = %catch.dispatch
+  %idxprom1 = sext i32 %idx2 to i64
+  %arrayidx2 = getelementptr inbounds [4 x i32], [4 x i32]* @array, i64 0, i64 %idxprom1
+  store i32 222, i32* %arrayidx2, align 4, !tbaa !2
+  catchret %0 to label %try.cont
+
+try.cont:                                         ; preds = %catch
+  %idxprom3 = sext i32 %idx3 to i64
+  %arrayidx4 = getelementptr inbounds [4 x i32], [4 x i32]* @array, i64 0, i64 %idxprom3
+  store i32 333, i32* %arrayidx4, align 4, !tbaa !2
+  ret void
+
+catchendblock:                                    ; preds = %catch.dispatch
+  catchendpad unwind to caller
+
+unreachable:                                      ; preds = %entry
+  unreachable
+}
+
+; CHECK-LABEL: global_array: # @global_array
+; CHECK: pushq %rbp
+; 	First array access
+; CHECK: movslq  %ecx, %[[idx:[^ ]*]]
+; CHECK: leaq    array(%rip), %[[base:[^ ]*]]
+; CHECK: movl    $111, (%[[base]],%[[idx]],4)
+;	Might throw an exception and return to below...
+; CHECK: callq   _CxxThrowException
+; 	Third array access must remat the address of array
+; CHECK: movslq  {{.*}}, %[[idx:[^ ]*]]
+; CHECK: leaq    array(%rip), %[[base:[^ ]*]]
+; CHECK: movl    $333, (%[[base]],%[[idx]],4)
+; CHECK: popq %rbp
+; CHECK: retq
+
+; CHECK: "?catch$2@?0?global_array@4HA":
+; CHECK: pushq   %rbp
+; CHECK: movslq  {{.*}}, %[[idx:[^ ]*]]
+; CHECK: leaq    array(%rip), %[[base:[^ ]*]]
+; CHECK: movl    $222, (%[[base]],%[[idx]],4)
+; CHECK: popq    %rbp
+; CHECK: retq                            # CATCHRET
+
+declare void @_CxxThrowException(i8*, %eh.ThrowInfo*)
+
+declare i32 @__CxxFrameHandler3(...)
+
+; Function Attrs: uwtable
+define void @access_imported() #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+entry:
+  store i32 111, i32* @imported, align 4, !tbaa !2
+  invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) #1
+          to label %unreachable unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %entry
+  %0 = catchpad [i8* null, i32 64, i8* null]
+          to label %catch unwind label %catchendblock
+
+catch:                                            ; preds = %catch.dispatch
+  store i32 222, i32* @imported, align 4, !tbaa !2
+  catchret %0 to label %try.cont
+
+try.cont:                                         ; preds = %catch
+  store i32 333, i32* @imported, align 4, !tbaa !2
+  ret void
+
+catchendblock:                                    ; preds = %catch.dispatch
+  catchendpad unwind to caller
+
+unreachable:                                      ; preds = %entry
+  unreachable
+}
+
+; CHECK-LABEL: access_imported: # @access_imported
+; CHECK: pushq %rbp
+; CHECK: movq    __imp_imported(%rip), %[[base:[^ ]*]]
+; CHECK: movl    $111, (%[[base]])
+;	Might throw an exception and return to below...
+; CHECK: callq   _CxxThrowException
+; 	Third access must reload the address of imported
+; CHECK: movq    __imp_imported(%rip), %[[base:[^ ]*]]
+; CHECK: movl    $333, (%[[base]])
+; CHECK: popq %rbp
+; CHECK: retq
+
+; CHECK: "?catch$2@?0?access_imported@4HA":
+; CHECK: pushq   %rbp
+; CHECK: movq    __imp_imported(%rip), %[[base:[^ ]*]]
+; CHECK: movl    $222, (%[[base]])
+; CHECK: popq    %rbp
+; CHECK: retq                            # CATCHRET
+
+
+attributes #0 = { uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { noreturn }
+
+!llvm.module.flags = !{!0}
+!llvm.ident = !{!1}
+
+!0 = !{i32 1, !"PIC Level", i32 2}
+!1 = !{!"clang version 3.8.0 "}
+!2 = !{!3, !3, i64 0}
+!3 = !{!"int", !4, i64 0}
+!4 = !{!"omnipotent char", !5, i64 0}
+!5 = !{!"Simple C/C++ TBAA"}
diff --git a/llvm/test/CodeGen/X86/cleanuppad-large-codemodel.ll b/llvm/test/CodeGen/X86/cleanuppad-large-codemodel.ll
new file mode 100644
index 00000000000..df866f9598a
--- /dev/null
+++ b/llvm/test/CodeGen/X86/cleanuppad-large-codemodel.ll
@@ -0,0 +1,27 @@
+; RUN: llc -mtriple=x86_64-pc-windows-msvc -code-model=large -o - < %s | FileCheck %s
+
+declare i32 @__CxxFrameHandler3(...)
+
+declare void @bar()
+
+define void @foo() personality i32 (...)* @__CxxFrameHandler3 {
+entry:
+  invoke void @bar()
+    to label %exit unwind label %cleanup
+cleanup:
+  %c = cleanuppad []
+  call void @bar()
+  cleanupret %c unwind to caller
+exit:
+  ret void
+}
+
+; CHECK: foo: # @foo
+; CHECK: movabsq $bar, %[[reg:[^ ]*]]
+; CHECK: callq *%[[reg]]
+; CHECK: retq
+
+; CHECK: "?dtor$2@?0?foo@4HA":
+; CHECK: movabsq $bar, %[[reg:[^ ]*]]
+; CHECK: callq *%[[reg]]
+; CHECK: retq                            # CLEANUPRET