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llvm-mirror/test/CodeGen/X86/stack-probe-size.ll
David Majnemer 84c4bd1a4c X86: Allow the stack probe size to be configurable per function
LLVM emits stack probes on Windows targets to ensure that the stack is
correctly accessed.  However, the amount of stack allocated before
emitting such a probe is hardcoded to 4096.

It is desirable to have this be configurable so that a function might
opt-out of stack probes.  Our level of granularity is at the function
level instead of, say, the module level to permit proper generation of
code after LTO.

Patch by Andrew H!

N.B.  The inliner needs to be updated to properly consider what happens
after inlining a function with a specific stack-probe-size into another
function with a different stack-probe-size.

llvm-svn: 225360
2015-01-07 18:14:07 +00:00

79 lines
1.6 KiB
LLVM

; This test is attempting to detect that the compiler correctly generates stack
; probe calls when the size of the local variables exceeds the specified stack
; probe size.
;
; Testing the default value of 4096 bytes makes sense, because the default
; stack probe size equals the page size (4096 bytes for all x86 targets), and
; this is unlikely to change in the future.
;
; RUN: llc < %s | FileCheck %s
target datalayout = "e-m:w-p:32:32-i64:64-f80:32-n8:16:32-S32"
target triple = "i686-pc-windows-msvc"
define i32 @test1() "stack-probe-size"="0" {
%buffer = alloca [4095 x i8]
ret i32 0
; CHECK-LABEL: _test1:
; CHECK-NOT: subl $4095, %esp
; CHECK: movl $4095, %eax
; CHECK: calll __chkstk
}
define i32 @test2() {
%buffer = alloca [4095 x i8]
ret i32 0
; CHECK-LABEL: _test2:
; CHECK-NOT: movl $4095, %eax
; CHECK: subl $4095, %esp
; CHECK-NOT: calll __chkstk
}
define i32 @test3() "stack-probe-size"="8192" {
%buffer = alloca [4095 x i8]
ret i32 0
; CHECK-LABEL: _test3:
; CHECK-NOT: movl $4095, %eax
; CHECK: subl $4095, %esp
; CHECK-NOT: calll __chkstk
}
define i32 @test4() "stack-probe-size"="0" {
%buffer = alloca [4096 x i8]
ret i32 0
; CHECK-LABEL: _test4:
; CHECK-NOT: subl $4096, %esp
; CHECK: movl $4096, %eax
; CHECK: calll __chkstk
}
define i32 @test5() {
%buffer = alloca [4096 x i8]
ret i32 0
; CHECK-LABEL: _test5:
; CHECK-NOT: subl $4096, %esp
; CHECK: movl $4096, %eax
; CHECK: calll __chkstk
}
define i32 @test6() "stack-probe-size"="8192" {
%buffer = alloca [4096 x i8]
ret i32 0
; CGECK-LABEL: _test6:
; CGECK-NOT: movl $4096, %eax
; CGECK: subl $4096, %esp
; CGECK-NOT: calll __chkstk
}