151741 2015-12-02 01:13:49 -0800 [JSC] Add a function attribute for Pure functions in B3 2015-12-02 14:17:27 -0800 1 1 1 Unclassified WebKit New Bugs WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED P2 Normal --- 1 benjamin benjamin commit-queue fpizlo keith_miller mark.lam msaboff saam oldest_to_newest 1145534 0 benjamin 2015-12-02 01:13:49 -0800 [JSC] Add a function attribute for Pure functions in B3 1145535 1 266435 benjamin 2015-12-02 01:16:39 -0800 Created attachment 266435 Patch 1145637 2 266435 ggaren 2015-12-02 11:17:28 -0800 Comment on attachment 266435 Patch View in context: https://bugs.webkit.org/attachment.cgi?id=266435&action=review r=me > Source/JavaScriptCore/b3/B3CCallValue.h:38 > + enum Pure { PureCall }; Usually we call this "enum PureCallTag { PureCall }". 1145725 3 benjamin 2015-12-02 14:12:46 -0800 Committed r192967: <http://trac.webkit.org/changeset/192967> 1145726 4 266435 fpizlo 2015-12-02 14:17:27 -0800 Comment on attachment 266435 Patch This doesn't belong here at all. A pure function can be labeled by setting its Effects appropriately. Also, I really hate the word "pure" since it has no precise meaning. Do you mean that a call to the function with the same incoming values will yield the same result? Do you also mean that the function has no hidden effects that cause it to require execution even if the result is unused? Do you also mean that it will never read any memory, or can it still read some memory? I created B3::Effects with the intent that it can answer all of these questions precisely: - You can say that a function reads no memory. - You can say that a function writes no memory. - You can say that a function is not control-dependent. - You can say that a function will not side-exit (for C functions a side-exit would be if it triggered unwinding - so this can always be cleared for all of the C functions we call). The strongest purity guarantee is "any call to this function with the same arguments will yield the same result". I believe that this guarantee can be expressed by saying that it does not read or write memory, does not have SSA effects, doesn't do any of the other things (control-dependent, side-exit, terminal). My goal with CSE was to have pure CSE rules on calls and patchpoints that do this. So, can we please roll this out? 266435 2015-12-02 01:16:39 -0800 2015-12-02 14:17:27 -0800 Patch bug-151741-20151202011615.patch text/plain 3582 benjamin U3VidmVyc2lvbiBSZXZpc2lvbjogMTkyOTQwCmRpZmYgLS1naXQgYS9Tb3VyY2UvSmF2YVNjcmlw dENvcmUvQ2hhbmdlTG9nIGIvU291cmNlL0phdmFTY3JpcHRDb3JlL0NoYW5nZUxvZwppbmRleCA1 YmNlNDk0MmQ2OTU0MDgyMGY0ODAwY2JjMDY4YWZmMTA5ZGE2ZGFmLi4xODA4MjNiYTU0OTQ4Y2U3 MGM3MmFjZDYzMjczMjViZjczMmIxNWE3IDEwMDY0NAotLS0gYS9Tb3VyY2UvSmF2YVNjcmlwdENv cmUvQ2hhbmdlTG9nCisrKyBiL1NvdXJjZS9KYXZhU2NyaXB0Q29yZS9DaGFuZ2VMb2cKQEAgLTEs MyArMSwyMCBAQAorMjAxNS0xMi0wMiAgQmVuamFtaW4gUG91bGFpbiAgPGJwb3VsYWluQGFwcGxl LmNvbT4KKworICAgICAgICBbSlNDXSBBZGQgYSBmdW5jdGlvbiBhdHRyaWJ1dGUgZm9yIFB1cmUg ZnVuY3Rpb25zIGluIEIzCisgICAgICAgIGh0dHBzOi8vYnVncy53ZWJraXQub3JnL3Nob3dfYnVn LmNnaT9pZD0xNTE3NDEKKworICAgICAgICBSZXZpZXdlZCBieSBOT0JPRFkgKE9PUFMhKS4KKwor ICAgICAgICBXZSBoYXZlIHBsZW50eSBvZiBmdW5jdGlvbnMgd2l0aG91dCBzaWRlIGVmZmVjdHMK KyAgICAgICAgd2hlbiBsb3dlcmluZyBERkcuCisgICAgICAgIFRoaXMgcGF0Y2ggYWRkcyB0aGUg IlB1cmVDYWxsIiBmbGFnIHRvIEIzJ3MgQ0NhbGwKKyAgICAgICAgdG8gbWFrZSBzdXJlIHRob3Nl IGZ1bmN0aW9ucyBkbyBub3QgcHJldmVudCBvcHRpbWl6YXRpb25zLgorCisgICAgICAgICogYjMv QjNDQ2FsbFZhbHVlLmg6CisgICAgICAgICogYjMvdGVzdGIzLmNwcDoKKyAgICAgICAgKEpTQzo6 QjM6OnRlc3RDYWxsU2ltcGxlUHVyZSk6CisgICAgICAgIChKU0M6OkIzOjpydW4pOgorCiAyMDE1 LTEyLTAxICBZdXN1a2UgU3V6dWtpICA8dXRhdGFuZS50ZWFAZ21haWwuY29tPgogCiAgICAgICAg IFtFUzZdIEltcGxlbWVudCBMTEludC9CYXNlbGluZSBTdXBwb3J0IGZvciBFUzYgR2VuZXJhdG9y cyBhbmQgZW5hYmxlIHRoaXMgZmVhdHVyZQpkaWZmIC0tZ2l0IGEvU291cmNlL0phdmFTY3JpcHRD b3JlL2IzL0IzQ0NhbGxWYWx1ZS5oIGIvU291cmNlL0phdmFTY3JpcHRDb3JlL2IzL0IzQ0NhbGxW YWx1ZS5oCmluZGV4IDFjNjVlOWI0MDEwNjAzMDdlM2Q1ZGY5MzI3OWVjYTkzNDIxOTVkODQuLjE1 ZDZiOTNlOGVmMTU4NmUxOGIzNmY0Mjc1OGM0ZjVlZmMxOTY1YzcgMTAwNjQ0Ci0tLSBhL1NvdXJj ZS9KYXZhU2NyaXB0Q29yZS9iMy9CM0NDYWxsVmFsdWUuaAorKysgYi9Tb3VyY2UvSmF2YVNjcmlw dENvcmUvYjMvQjNDQ2FsbFZhbHVlLmgKQEAgLTM1LDYgKzM1LDcgQEAgbmFtZXNwYWNlIEpTQyB7 IG5hbWVzcGFjZSBCMyB7CiAKIGNsYXNzIEpTX0VYUE9SVF9QUklWQVRFIENDYWxsVmFsdWUgOiBw dWJsaWMgVmFsdWUgewogcHVibGljOgorICAgIGVudW0gUHVyZSB7IFB1cmVDYWxsIH07CiAgICAg c3RhdGljIGJvb2wgYWNjZXB0cyhPcGNvZGUgb3Bjb2RlKSB7IHJldHVybiBvcGNvZGUgPT0gQ0Nh bGw7IH0KIAogICAgIH5DQ2FsbFZhbHVlKCk7CkBAIC01MCw2ICs1MSwxMiBAQCBwcml2YXRlOgog ICAgICAgICAsIGVmZmVjdHMoRWZmZWN0czo6Zm9yQ2FsbCgpKQogICAgIHsKICAgICB9CisKKyAg ICB0ZW1wbGF0ZTx0eXBlbmFtZS4uLiBBcmd1bWVudHM+CisgICAgQ0NhbGxWYWx1ZSh1bnNpZ25l ZCBpbmRleCwgVHlwZSB0eXBlLCBPcmlnaW4gb3JpZ2luLCBQdXJlLCBBcmd1bWVudHMuLi4gYXJn dW1lbnRzKQorICAgICAgICA6IFZhbHVlKGluZGV4LCBDaGVja2VkT3Bjb2RlLCBDQ2FsbCwgdHlw ZSwgb3JpZ2luLCBhcmd1bWVudHMuLi4pCisgICAgeworICAgIH0KIH07CiAKIH0gfSAvLyBuYW1l c3BhY2UgSlNDOjpCMwpkaWZmIC0tZ2l0IGEvU291cmNlL0phdmFTY3JpcHRDb3JlL2IzL3Rlc3Ri My5jcHAgYi9Tb3VyY2UvSmF2YVNjcmlwdENvcmUvYjMvdGVzdGIzLmNwcAppbmRleCBhYjQxYjYy MzRkNjU4MGM1NzljMThlOTIyMTVmYjAzZTkzNzVkM2RiLi42OTljMzYxNGU3NTNhMjY4MWI2MDk0 NjkxMjRlYzhiZjZhOGI1NmFlIDEwMDY0NAotLS0gYS9Tb3VyY2UvSmF2YVNjcmlwdENvcmUvYjMv dGVzdGIzLmNwcAorKysgYi9Tb3VyY2UvSmF2YVNjcmlwdENvcmUvYjMvdGVzdGIzLmNwcApAQCAt NDYyNSw2ICs0NjI1LDIxIEBAIHZvaWQgdGVzdENhbGxTaW1wbGUoaW50IGEsIGludCBiKQogICAg IENIRUNLKGNvbXBpbGVBbmRSdW48aW50Pihwcm9jLCBhLCBiKSA9PSBhICsgYik7CiB9CiAKK3Zv aWQgdGVzdENhbGxTaW1wbGVQdXJlKGludCBhLCBpbnQgYikKK3sKKyAgICBQcm9jZWR1cmUgcHJv YzsKKyAgICBCYXNpY0Jsb2NrKiByb290ID0gcHJvYy5hZGRCbG9jaygpOworICAgIHJvb3QtPmFw cGVuZE5ldzxDb250cm9sVmFsdWU+KAorICAgICAgICBwcm9jLCBSZXR1cm4sIE9yaWdpbigpLAor ICAgICAgICByb290LT5hcHBlbmROZXc8Q0NhbGxWYWx1ZT4oCisgICAgICAgICAgICBwcm9jLCBJ bnQzMiwgT3JpZ2luKCksIENDYWxsVmFsdWU6OlB1cmVDYWxsLAorICAgICAgICAgICAgcm9vdC0+ YXBwZW5kTmV3PENvbnN0UHRyVmFsdWU+KHByb2MsIE9yaWdpbigpLCBiaXR3aXNlX2Nhc3Q8dm9p ZCo+KHNpbXBsZUZ1bmN0aW9uKSksCisgICAgICAgICAgICByb290LT5hcHBlbmROZXc8QXJndW1l bnRSZWdWYWx1ZT4ocHJvYywgT3JpZ2luKCksIEdQUkluZm86OmFyZ3VtZW50R1BSMCksCisgICAg ICAgICAgICByb290LT5hcHBlbmROZXc8QXJndW1lbnRSZWdWYWx1ZT4ocHJvYywgT3JpZ2luKCks IEdQUkluZm86OmFyZ3VtZW50R1BSMSkpKTsKKworICAgIENIRUNLKGNvbXBpbGVBbmRSdW48aW50 Pihwcm9jLCBhLCBiKSA9PSBhICsgYik7Cit9CisKIGludCBmdW5jdGlvbldpdGhIZWxsYUFyZ3Vt ZW50cyhpbnQgYSwgaW50IGIsIGludCBjLCBpbnQgZCwgaW50IGUsIGludCBmLCBpbnQgZywgaW50 IGgsIGludCBpLCBpbnQgaiwgaW50IGssIGludCBsLCBpbnQgbSwgaW50IG4sIGludCBvLCBpbnQg cCwgaW50IHEsIGludCByLCBpbnQgcywgaW50IHQsIGludCB1LCBpbnQgdiwgaW50IHcsIGludCB4 LCBpbnQgeSwgaW50IHopCiB7CiAgICAgcmV0dXJuIChhIDw8IDApICsgKGIgPDwgMSkgKyAoYyA8 PCAyKSArIChkIDw8IDMpICsgKGUgPDwgNCkgKyAoZiA8PCA1KSArIChnIDw8IDYpICsgKGggPDwg NykgKyAoaSA8PCA4KSArIChqIDw8IDkpICsgKGsgPDwgMTApICsgKGwgPDwgMTEpICsgKG0gPDwg MTIpICsgKG4gPDwgMTMpICsgKG8gPDwgMTQpICsgKHAgPDwgMTUpICsgKHEgPDwgMTYpICsgKHIg PDwgMTcpICsgKHMgPDwgMTgpICsgKHQgPDwgMTkpICsgKHUgPDwgMjApICsgKHYgPDwgMjEpICsg KHcgPDwgMjIpICsgKHggPDwgMjMpICsgKHkgPDwgMjQpICsgKHogPDwgMjUpOwpAQCAtNTg4OSw2 ICs1OTA0LDcgQEAgdm9pZCBydW4oY29uc3QgY2hhciogZmlsdGVyKQogICAgIFJVTih0ZXN0U3Bp bGxGUCgpKTsKIAogICAgIFJVTih0ZXN0Q2FsbFNpbXBsZSgxLCAyKSk7CisgICAgUlVOKHRlc3RD YWxsU2ltcGxlUHVyZSgxLCAyKSk7CiAgICAgUlVOKHRlc3RDYWxsRnVuY3Rpb25XaXRoSGVsbGFB cmd1bWVudHMoKSk7CiAKICAgICBSVU4odGVzdFJldHVybkRvdWJsZSgwLjApKTsK