94408 2012-08-17 19:15:40 -0700 DFG CSE should be more honest about when it changed the IR 2012-08-17 23:01:56 -0700 1 1 1 Unclassified WebKit JavaScriptCore 528+ (Nightly build) All All RESOLVED FIXED P2 Normal --- 94205 1 fpizlo fpizlo oldest_to_newest 698893 0 fpizlo 2012-08-17 19:15:40 -0700 Previously, the CSE would sometimes lie and say that it changed nothing. But that can lead to humorous inconsistencies. For example: a: GetGlobalVar(thingy) b: CheckStructure(@a, 0x1234) c: GetGlobalVar(thingy) d: CheckStructure(@c, 0x2345) This code will never complete, since there is no way that 'thingy' can simultaneously pass both structure checks. But previously, we wouldn't realize this, because even though the CSE would modify the code to be: a: GetGlobalVar(thingy) b: CheckStructure(@a, 0x1234) c: Phantom() d: CheckStructure(@a, 0x2345) It wouldn't let the optimization fixpoint know, and the optimization fixpoint wouldn't rerun the CFA. Currently this "bug" is asymptomatic but it would become symptomatic if we started relying more the CFA results of things like CheckStructure. 698896 1 159257 fpizlo 2012-08-17 19:26:17 -0700 Created attachment 159257 the patch 698922 2 159257 ggaren 2012-08-17 22:57:45 -0700 Comment on attachment 159257 the patch r=me 698923 3 fpizlo 2012-08-17 23:01:56 -0700 Landed in http://trac.webkit.org/changeset/125964 159257 2012-08-17 19:26:17 -0700 2012-08-17 22:57:44 -0700 the patch fixcse_patch_1.diff text/plain 2194 fpizlo SW5kZXg6IFNvdXJjZS9KYXZhU2NyaXB0Q29yZS9DaGFuZ2VMb2cKPT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PQotLS0gU291 cmNlL0phdmFTY3JpcHRDb3JlL0NoYW5nZUxvZwkocmV2aXNpb24gMTI1OTYxKQorKysgU291cmNl L0phdmFTY3JpcHRDb3JlL0NoYW5nZUxvZwkod29ya2luZyBjb3B5KQpAQCAtMSwzICsxLDE3IEBA CisyMDEyLTA4LTE3ICBGaWxpcCBQaXpsbyAgPGZwaXpsb0BhcHBsZS5jb20+CisKKyAgICAgICAg REZHIENTRSBzaG91bGQgYmUgbW9yZSBob25lc3QgYWJvdXQgd2hlbiBpdCBjaGFuZ2VkIHRoZSBJ UgorICAgICAgICBodHRwczovL2J1Z3Mud2Via2l0Lm9yZy9zaG93X2J1Zy5jZ2k/aWQ9OTQ0MDgK KworICAgICAgICBSZXZpZXdlZCBieSBOT0JPRFkgKE9PUFMhKS4KKworICAgICAgICBUaGUgQ1NF IHBoYXNlIG5vdyBhbHdheXMgcmV0dXJucyB0cnVlIGlmIGl0IGNoYW5nZWQgdGhlIElSLgorCisg ICAgICAgICogZGZnL0RGR0NTRVBoYXNlLmNwcDoKKyAgICAgICAgKEpTQzo6REZHOjpDU0VQaGFz ZTo6c2V0UmVwbGFjZW1lbnQpOgorICAgICAgICAoSlNDOjpERkc6OkNTRVBoYXNlOjplbGltaW5h dGUpOgorICAgICAgICAoSlNDOjpERkc6OkNTRVBoYXNlOjpwZXJmb3JtTm9kZUNTRSk6CisKIDIw MTItMDgtMTcgIEZpbGlwIFBpemxvICA8ZnBpemxvQGFwcGxlLmNvbT4KIAogICAgICAgICBERkcg aXMgc3RpbGwgdG9vIHBlc3NpbWlzdGljIGFib3V0IHdoYXQgY29uc3RpdHV0ZXMgYSBzaWRlLWVm ZmVjdCBvbiBhcnJheSBhY2Nlc3NlcwpJbmRleDogU291cmNlL0phdmFTY3JpcHRDb3JlL2RmZy9E RkdDU0VQaGFzZS5jcHAKPT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09PT09 PT09PT09PT09PT09PT09PT09PT09PT09PQotLS0gU291cmNlL0phdmFTY3JpcHRDb3JlL2RmZy9E RkdDU0VQaGFzZS5jcHAJKHJldmlzaW9uIDEyNTk1OSkKKysrIFNvdXJjZS9KYXZhU2NyaXB0Q29y ZS9kZmcvREZHQ1NFUGhhc2UuY3BwCSh3b3JraW5nIGNvcHkpCkBAIC04NDMsNiArODQzLDggQEAg cHJpdmF0ZToKICAgICAgICAgLy8gQXQgdGhpcyBwb2ludCB3ZSB3aWxsIGVsaW1pbmF0ZSBhbGwg cmVmZXJlbmNlcyB0byB0aGlzIG5vZGUuCiAgICAgICAgIG1fcmVwbGFjZW1lbnRzW21fY29tcGls ZUluZGV4XSA9IHJlcGxhY2VtZW50OwogICAgICAgICAKKyAgICAgICAgbV9jaGFuZ2VkID0gdHJ1 ZTsKKyAgICAgICAgCiAgICAgICAgIHJldHVybiB0cnVlOwogICAgIH0KICAgICAKQEAgLTg1Niw2 ICs4NTgsOCBAQCBwcml2YXRlOgogICAgICAgICBBU1NFUlQobm9kZS5yZWZDb3VudCgpID09IDEp OwogICAgICAgICBBU1NFUlQobm9kZS5tdXN0R2VuZXJhdGUoKSk7CiAgICAgICAgIG5vZGUuc2V0 T3BBbmREZWZhdWx0RmxhZ3MoUGhhbnRvbSk7CisgICAgICAgIAorICAgICAgICBtX2NoYW5nZWQg PSB0cnVlOwogICAgIH0KICAgICAKICAgICB2b2lkIGVsaW1pbmF0ZShOb2RlSW5kZXggbm9kZUlu ZGV4LCBOb2RlVHlwZSBwaGFudG9tVHlwZSA9IFBoYW50b20pCkBAIC04NjcsNiArODcxLDggQEAg cHJpdmF0ZToKICAgICAgICAgICAgIHJldHVybjsKICAgICAgICAgQVNTRVJUKG5vZGUubXVzdEdl bmVyYXRlKCkpOwogICAgICAgICBub2RlLnNldE9wQW5kRGVmYXVsdEZsYWdzKHBoYW50b21UeXBl KTsKKyAgICAgICAgCisgICAgICAgIG1fY2hhbmdlZCA9IHRydWU7CiAgICAgfQogICAgIAogICAg IHZvaWQgcGVyZm9ybU5vZGVDU0UoTm9kZSYgbm9kZSkKQEAgLTk4Miw3ICs5ODgsNyBAQCBwcml2 YXRlOgogICAgICAgICAgICAgCiAgICAgICAgIGNhc2UgR2V0TG9jYWxVbmxpbmtlZDogewogICAg ICAgICAgICAgTm9kZUluZGV4IHJlbGV2YW50TG9jYWxPcElnbm9yZWQ7Ci0gICAgICAgICAgICBt X2NoYW5nZWQgfD0gc2V0UmVwbGFjZW1lbnQoZ2V0TG9jYWxMb2FkRWxpbWluYXRpb24obm9kZS51 bmxpbmtlZExvY2FsKCksIHJlbGV2YW50TG9jYWxPcElnbm9yZWQsIHRydWUpKTsKKyAgICAgICAg ICAgIHNldFJlcGxhY2VtZW50KGdldExvY2FsTG9hZEVsaW1pbmF0aW9uKG5vZGUudW5saW5rZWRM b2NhbCgpLCByZWxldmFudExvY2FsT3BJZ25vcmVkLCB0cnVlKSk7CiAgICAgICAgICAgICBicmVh azsKICAgICAgICAgfQogICAgICAgICAgICAgCg==