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Hi, GlobalsAA, during propagation of mod-ref behavior in the call graph, looks at library functions (in GlobalsAAResult::AnalyzeCallGraph: F->isDeclaration() check), for attributes, and if the function does not have the onlyReadsMemory attribute set, forgets it. I noticed that library functions such as malloc/realloc do not have the attributes doesNotAccessMemory or onlyReadsMemory respectively set (FunctionAttrs.cpp). This leads...

...s, > > James > > On Wed, 2 Dec 2015 at 14:07 Vaivaswatha Nagaraj via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > >> Hi, >> >> GlobalsAA, during propagation of mod-ref behavior in the call graph, >> looks at library functions (in GlobalsAAResult::AnalyzeCallGraph: >> F->isDeclaration() check), for attributes, and if the function does not >> have the onlyReadsMemory attribute set, forgets it. >> >> I noticed that library functions such as malloc/realloc do not have the >> attributes doesNotAccessMemory or onlyReadsMemory resp...

...39;re understanding correctly, but I don't understand what you're saying will go badly with the malloc example. Quoting the start of the thread: <<< The intention behind introducing this attribute is to relax the conditions in GlobalsAA as below: (this code is in GlobalsAAResult::AnalyzeCallGraph) if (F->isDeclaration()) { // Try to get mod/ref behaviour from function attributes. - if (F->doesNotAccessMemory()) { + if (F->doesNotAccessMemory() || F->onlyAccessesArgMemory()) { // Can't do better than that! } else if (F->onl...

...ion to what are already set): malloc/free: HasInaccessibleState, ReadNone printf: HasInaccessibleState, ArgMemOnly realloc: HasInaccessibleState, ReadOnly (not sure). The intention behind introducing this attribute is to relax the conditions in GlobalsAA as below: (this code is in GlobalsAAResult::AnalyzeCallGraph) if (F->isDeclaration()) { // Try to get mod/ref behaviour from function attributes. - if (F->doesNotAccessMemory()) { + if (F->doesNotAccessMemory() || F->onlyAccessesArgMemory()) { // Can't do better than that! } else if (F->on...

...malloc/free: HasInaccessibleState, ReadNone > printf: HasInaccessibleState, ArgMemOnly > realloc: HasInaccessibleState, ReadOnly (not sure). > > The intention behind introducing this attribute is to relax the conditions > in GlobalsAA as below: > (this code is in GlobalsAAResult::AnalyzeCallGraph) > > if (F->isDeclaration()) { > // Try to get mod/ref behaviour from function attributes. > - if (F->doesNotAccessMemory()) { > + if (F->doesNotAccessMemory() || F->onlyAccessesArgMemory()) { > // Can't do better than that!...

...t; you're saying will go badly with the malloc example. Quoting the > > start of the thread: > > > > <<< > > The intention behind introducing this attribute is to relax the > > conditions in GlobalsAA as below: > > (this code is in GlobalsAAResult::AnalyzeCallGraph) > > if (F->isDeclaration()) { > > // Try to get mod/ref behaviour from function attributes. > > - if (F->doesNotAccessMemory()) { > > + if (F->doesNotAccessMemory() || > > F->onlyAccessesArgMemory()) { > > // Can...

...;>> printf: HasInaccessibleState, ArgMemOnly >>> realloc: HasInaccessibleState, ReadOnly (not sure). >>> >>> The intention behind introducing this attribute is to relax the >>> conditions in GlobalsAA as below: >>> (this code is in GlobalsAAResult::AnalyzeCallGraph) >>> >>> if (F->isDeclaration()) { >>> // Try to get mod/ref behaviour from function attributes. >>> - if (F->doesNotAccessMemory()) { >>> + if (F->doesNotAccessMemory() || F->onlyAccessesArgMemory()) { >>&...

...sibleState, ReadNone >> printf: HasInaccessibleState, ArgMemOnly >> realloc: HasInaccessibleState, ReadOnly (not sure). >> >> The intention behind introducing this attribute is to relax the >> conditions in GlobalsAA as below: >> (this code is in GlobalsAAResult::AnalyzeCallGraph) >> >> if (F->isDeclaration()) { >> // Try to get mod/ref behaviour from function attributes. >> - if (F->doesNotAccessMemory()) { >> + if (F->doesNotAccessMemory() || F->onlyAccessesArgMemory()) { >> // Can...

...adly with the malloc example. Quoting the > > > start of the thread: > > > > > > <<< > > > The intention behind introducing this attribute is to relax the > > > conditions in GlobalsAA as below: > > > (this code is in GlobalsAAResult::AnalyzeCallGraph) > > > if (F->isDeclaration()) { > > > // Try to get mod/ref behaviour from function attributes. > > > - if (F->doesNotAccessMemory()) { > > > + if (F->doesNotAccessMemory() || > > > F->onlyAccessesArgMemory()) { &...

...;>> printf: HasInaccessibleState, ArgMemOnly >>> realloc: HasInaccessibleState, ReadOnly (not sure). >>> >>> The intention behind introducing this attribute is to relax the >>> conditions in GlobalsAA as below: >>> (this code is in GlobalsAAResult::AnalyzeCallGraph) >>> >>> if (F->isDeclaration()) { >>> // Try to get mod/ref behaviour from function attributes. >>> - if (F->doesNotAccessMemory()) { >>> + if (F->doesNotAccessMemory() || F->onlyAccessesArgMemory()) { >>&...

...> > > > > > > <<< > > > > > > The intention behind introducing this attribute is to relax > > > > > the > > > > > > conditions in GlobalsAA as below: > > > > > > (this code is in GlobalsAAResult::AnalyzeCallGraph) > > > > > > if (F->isDeclaration()) { > > > > > > // Try to get mod/ref behaviour from function attributes. > > > > > > - if (F->doesNotAccessMemory()) { > > > > > > + if (F->doesNotAccessMemory() || > > &g...

...> > On Wed, 2 Dec 2015 at 14:07 Vaivaswatha Nagaraj via llvm-dev < > llvm-dev at lists.llvm.org > wrote: > > > > > > > Hi, > > GlobalsAA, during propagation of mod-ref behavior in the call graph, > looks at library functions (in GlobalsAAResult::AnalyzeCallGraph: > F->isDeclaration() check), for attributes, and if the function does > not have the onlyReadsMemory attribute set, forgets it. > > > > I noticed that library functions such as malloc/realloc do not have > the attributes doesNotAccessMemory or onlyReadsMemory respectivel...

...gt; >> > > > > > The intention behind introducing this attribute is to relax >> > > > > > the >> > >> > > > > > conditions in GlobalsAA as below: >> > >> > > > > > (this code is in GlobalsAAResult::AnalyzeCallGraph) >> > >> > > > > > if (F->isDeclaration()) { >> > >> > > > > > // Try to get mod/ref behaviour from function attributes. >> > >> > > > > > - if (F->doesNotAccessMemory()) { >> > >> > &g...

...gt; start of the thread: > > > > > > > > <<< > > > > The intention behind introducing this attribute is to relax the > > > > conditions in GlobalsAA as below: > > > > (this code is in GlobalsAAResult::AnalyzeCallGraph) > > > > if (F->isDeclaration()) { > > > > // Try to get mod/ref behaviour from function attributes. > > > > - if (F->doesNotAccessMemory()) { > > > > + if (F->doesNotAccessMemory() || >...

...ArgMemOnly >>>>> realloc: HasInaccessibleState, ReadOnly (not sure). >>>>> >>>>> The intention behind introducing this attribute is to relax the >>>>> conditions in GlobalsAA as below: >>>>> (this code is in GlobalsAAResult::AnalyzeCallGraph) >>>>> >>>>> if (F->isDeclaration()) { >>>>> // Try to get mod/ref behaviour from function attributes. >>>>> - if (F->doesNotAccessMemory()) { >>>>> + if (F->doesNotAccessMemory() || F-...

Sigh... let me try that last part again: Maybe GlobalsAA and/or a GlobalsAA-centric attribution pass could partition writes as: 1. Stores to local allocas 2. Stores through pointer parameters 3. Stores to globals defined in this compilation unit 4. Other Attributing functions with attributes: readonly: only writes of type 1 argmemonly: only writes of type 1/2 almost-readonly: only