diff options
| -rw-r--r-- | lib/Target/X86/X86FrameLowering.cpp | 20 | ||||
| -rw-r--r-- | test/CodeGen/X86/segmented-stacks.ll | 36 |
2 files changed, 43 insertions, 13 deletions
diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp index 182af84f7c..27b762af69 100644 --- a/lib/Target/X86/X86FrameLowering.cpp +++ b/lib/Target/X86/X86FrameLowering.cpp @@ -1306,6 +1306,10 @@ GetScratchRegister(bool Is64Bit, const MachineFunction &MF) { } } +// The stack limit in the TCB is set to this many bytes above the actual stack +// limit. +static const uint64_t kSplitStackAvailable = 256; + void X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { MachineBasicBlock &prologueMBB = MF.front(); @@ -1360,16 +1364,24 @@ X86FrameLowering::adjustForSegmentedStacks(MachineFunction &MF) const { TlsReg = X86::FS; TlsOffset = 0x70; - BuildMI(checkMBB, DL, TII.get(X86::LEA64r), ScratchReg).addReg(X86::RSP) - .addImm(0).addReg(0).addImm(-StackSize).addReg(0); + if (StackSize < kSplitStackAvailable) + ScratchReg = X86::RSP; + else + BuildMI(checkMBB, DL, TII.get(X86::LEA64r), ScratchReg).addReg(X86::RSP) + .addImm(0).addReg(0).addImm(-StackSize).addReg(0); + BuildMI(checkMBB, DL, TII.get(X86::CMP64rm)).addReg(ScratchReg) .addReg(0).addImm(0).addReg(0).addImm(TlsOffset).addReg(TlsReg); } else { TlsReg = X86::GS; TlsOffset = 0x30; - BuildMI(checkMBB, DL, TII.get(X86::LEA32r), ScratchReg).addReg(X86::ESP) - .addImm(0).addReg(0).addImm(-StackSize).addReg(0); + if (StackSize < kSplitStackAvailable) + ScratchReg = X86::ESP; + else + BuildMI(checkMBB, DL, TII.get(X86::LEA32r), ScratchReg).addReg(X86::ESP) + .addImm(0).addReg(0).addImm(-StackSize).addReg(0); + BuildMI(checkMBB, DL, TII.get(X86::CMP32rm)).addReg(ScratchReg) .addReg(0).addImm(0).addReg(0).addImm(TlsOffset).addReg(TlsReg); } diff --git a/test/CodeGen/X86/segmented-stacks.ll b/test/CodeGen/X86/segmented-stacks.ll index c28c31911d..4f529c119f 100644 --- a/test/CodeGen/X86/segmented-stacks.ll +++ b/test/CodeGen/X86/segmented-stacks.ll @@ -20,8 +20,7 @@ false: ; X32: test_basic: -; X32: leal -12(%esp), %ecx -; X32-NEXT: cmpl %gs:48, %ecx +; X32: cmpl %gs:48, %esp ; X32: pushl $4 ; X32-NEXT: pushl $12 @@ -41,8 +40,7 @@ false: ; X64: test_basic: -; X64: leaq -24(%rsp), %r11 -; X64-NEXT: cmpq %fs:112, %r11 +; X64: cmpq %fs:112, %rsp ; X64: movabsq $24, %r10 ; X64-NEXT: movabsq $0, %r11 @@ -66,17 +64,14 @@ define i32 @test_nested(i32 * nest %closure, i32 %other) { %result = add i32 %other, %addend ret i32 %result -; X32: leal (%esp), %edx -; X32-NEXT: cmpl %gs:48, %edx - +; X32: cmpl %gs:48, %esp ; X32: pushl $4 ; X32-NEXT: pushl $0 ; X32-NEXT: calll __morestack ; X32-NEXT: ret -; X64: leaq (%rsp), %r11 -; X64-NEXT: cmpq %fs:112, %r11 +; X64: cmpq %fs:112, %rsp ; X64: movq %r10, %rax ; X64-NEXT: movabsq $0, %r10 @@ -86,3 +81,26 @@ define i32 @test_nested(i32 * nest %closure, i32 %other) { ; X64-NEXT: movq %rax, %r10 } + +define void @test_large() { + %mem = alloca i32, i32 10000 + call void @dummy_use (i32* %mem, i32 0) + ret void + +; X32: leal -40012(%esp), %ecx +; X32-NEXT: cmpl %gs:48, %ecx + +; X32: pushl $0 +; X32-NEXT: pushl $40012 +; X32-NEXT: calll __morestack +; X32-NEXT: ret + +; X64: leaq -40008(%rsp), %r11 +; X64-NEXT: cmpq %fs:112, %r11 + +; X64: movabsq $40008, %r10 +; X64-NEXT: movabsq $0, %r11 +; X64-NEXT: callq __morestack +; X64-NEXT: ret + +} |